INFLUENCES ON SCHOOL-AGE CHILDREN’S MILK AND SOFT DRINK INTAKE
by
ARAX BALIAN
Submitted in Partial Fulfillment of the requirements
For the degree of Doctor of Philosophy
Dissertation Adviser: Dr Elizabeth Madigan
Frances Payne Bolton School of Nursing
CASE WESTERN RESERVE UNIVERSITY
January, 2009
i
CASE WESTERN RESERVE UNIVERSITY
SCHOOL OF GRADUATE STUDIES
We hereby approve the thesis/dissertation of
______Arax Balian candidate for the _____Ph.D______degree*.
(signed) ______Elizabeth Madigan ______(chair of the committee)
______Donna A. Dowling ______
______Susan Tullai-McGuinness______
______Hope Barkoukis ______
______
______
(date) ______November______14, 2008
*We also certify that written approval has been obtained for any proprietary material contained therein.
ii
Dedication
This dissertation is dedicated to the memory of my father who would have been so proud of my accomplishments. It is also dedicated to my husband, Armand, who has provided me with his love and support and my children, Areen and Ayk, who have been the source of my inspiration.
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Table of Contents
Page
Table of Contents ------iii
List of Tables ------vii
List of Figures ------viii
Acknowledgements ------ix
Abstract ------xi
CHAPTER I: Introduction ------1
Introduction ------1
Problem ------2
Background and significance ------3 Milk and soft drink intake among American children ------3
Effects of milk and soft drink intake on children’s health ------6
Purpose ------9 Theoretical framework ------9
Study concepts ------15
Definition of terms ------18
Research questions ------20
Significance of the study ------21
CHAPTER II: Review of the Literature ------23
Overview of Childhood Overweight and Obesity ------23
Dietary Recommendations and Guidelines for Children ------28
iv
Cognitive development ------31
School-age children’s cognitive development ------31
Cognitive development, health beliefs, and food choice ------34
Factors influencing school-age children’s milk and soft drink intake ------36
School-age children’s milk and soft drink intake ------36
Influencing factors investigated in this study ------46
Other influences ------63
Summary for literature review ------66
CHAPTER III: Methods ------68
Design ------68
Setting ------68
Sample ------69
Sample size determination ------70
Sampling procedure ------72 Measurement ------72
Questionnaires ------73
Outcome variables ------78
Influencing factors ------78
Covariates ------82
Procedure ------84
Pilot study ------84
Main study ------85
Data analysis ------86
v
Description ------86
Preliminary analysis ------86
Analysis of research questions ------87
Protection of human subjects ------90
CHAPTER IV: Results ------92
Description ------93
Demographic characteristics ------93
Description of eating behaviors and patterns of milk and soft drink
intake ------94
Description of study variables ------99
Preliminary analysis ------100
Analysis of research questions ------102
The Theory of Planned Behavior constructs ------102
Gender, ethnicity, and BMI differences ------110 Summary ------120
CHAPTER V: Discussion ------122
Discussion of Results ------122
Description of eating behaviors and patterns of milk and soft drink
intake ------122
Analysis of research questions ------127
Prediction of milk/soda drinking behaviors ------127
Prediction of intention ------129
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Prediction of attitude, Subjective norm, and perceived
behavioral control ------131
Gender, ethnicity, and BMI differences ------135
Implications for practice, theory and policy ------138 Implications for practice ------138
Implications for theory ------138
Implications for policy ------139
Limitations of the Study ------140
Recommendations for Future Research ------141
Summary ------142
APPENDIX A: Demographic Characteristics Form: Tell me about yourself------144
APPENDIX B: 24-hour dietary recall for milk and soft drink intake ------145
APPENDIX C: Milk Intake Questionnaire ------147 APPENDIX D: Soda Pop Intake Questionnaire ------154
BIBLIOGRAPHY ------161
vii
List of Tables
Page
Table 1: Summary of findings about school-age children’s milk and
soft drink intake ------39
Table 2: Summary of relationships between influencing factors and milk
and soft drink intake ------47
Table 3: Ranges of the items in the Milk Intake Questionnaire from the
Pilot study ------75
Table 4: Ranges of the items in the Soda Pop Intake Questionnaire from the
Pilot study------76
Table 5: Frequencies of demographic characteristics of the study sample ------94
Table 6: Frequencies of eating behaviors and patterns of milk and
soft drink intake ------97
Table 7: Summary of descriptive statistics of the study variables ------100
Table 8: Gender differences in the milk and soda pop variables 111
Table 9: Race/ethnicity differences in the milk and soda pop variables ------115
Table 10: BMI differences in the milk and soda pop variables ------118
viii
List of Figures
Page
Figure 1: Theoretical Model of the Theory of Reasoned Action and
Theory of Planned Behavior ------10
Figure 2: Theoretical Model of the Study Based on the Theory of Planned
Behavior ------16
Figure 3: Substruction diagram of the study ------17
Figure 4: Path diagram for explanation of milk intake ------108
Figure 5: Path diagram for explanation of soft drink intake ------109
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Acknowledgements
I would like to express my gratitude to the following people, without whom I
could not have completed my doctoral degree. First, I would like to thank Elizabeth
Madigan, PhD, RN, FAAN, my academic advisor and the chairperson of my dissertation
committee, for her insightful guidance during my doctoral study. Despite the obstacles
that we faced, she made all efforts to ensure the fruition of this study. I also would like to
thank my dissertation committee members: Donna Dowling, PhD, RN, Susan Tullai-
McGuinness, PhD, RN, and Hope Barkoukis, PhD, RD, LD for their valuable input based on their expertise. I am also grateful to Gail McCain, PhD, RN, FAAN, for her support and input during the initial phase of the development of this study.
Next, I wish to extend my appreciation to the staff of the research office at Kaiser
Permanente Ohio, Bedford Heights and their previous director, Mrs Lisaann Gittner, who
made all efforts to help me collect my dissertation data from their facilities. I also wish to thank the Midwest Nursing Research Society for the financial support they provided me
through the 2007 Dissertation Research Grant award.
Finally, I would like to extend my gratitude to the following people who always
stood by me and helped me fulfill my dreams: to my mother, who has guided me during
my undergraduate nursing education, has been my role model as a pediatric nurse, and has been a devoted mother to me and a grandmother to my children enabling me
accomplish my graduate studies; to my aunts, brothers and sister-in-law, who have all
provided genuine and affectionate care to my two children while I pursued my doctoral
education and dissertation defense. Last but not least, my deepest gratitude goes to my
x husband, Armand, without whose support, patience, and encouragement I could not have started and completed my doctoral degree and my two children, Areen and Ayk, whose emotional support and true patience have allowed me to pursue my doctoral degree.
xi
Influences on School-Age Children’s Milk and Soft Drink Intake
Abstract
By
ARAX BALIAN
Over the past decades milk intake among 6-to11-year-olds declined 24% among boys and 32% among girls. Concomitantly, consumption of calorie and carbohydrate-rich
soft drinks doubled, raising concerns related to overweight. Prevalence of childhood
overweight has more than tripled since 1976 leading to serious health conditions. A
cross-sectional descriptive correlational study was undertaken using the Theory of
Planned Behavior. The purposes were to: (1) determine influences on school-age
children’s milk and soft drink intake and (2) determine the effect of gender, ethnicity, and
body mass index (BMI) on behavioral beliefs, normative beliefs, control beliefs, attitude,
subjective norm, perceived behavioral control, intention, and milk/soft drink intake
behaviors. Using the roster of Kaiser Permanente Ohio, a random sample of six hundred
10 to 11-year-olds were asked to complete a mailed survey including a demographics form, 24-hour dietary recall, and Milk and Soda Pop Intake Questionnaires. Ninety-seven children responded.
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The majority of the children had ≥ 1 glass of milk on a usual day during the school
week and two-thirds consumed soft drinks. Multiple regression was used to explain the
relationships among the variables. Intention predicted milk and soda intake, attitude had
the strongest contribution, followed by perceived behavioral control in predicting soda
intention. Within the beliefs, taste and being healthy predicted attitudes, friends predicted
subjective norms, and availability of milk in home refrigerator predicted perceived
behavioral control to drink milk. No gender and BMI differences were found in the milk
and soda TPB variables and both behaviors. Compared to the minority group, white participants had: stronger intention to drink milk, stronger perception that drinking milk makes them healthy, that someone in their family thinks they should drink milk every day, and that having milk in home refrigerator makes it easier to drink it. Compared to
the white participants, the minority group had stronger perception that someone in their family and friends think they should drink soda every day and they drank significantly more soda. Ultimately, prospective studies assessing beverage patterns over time and replication of this study with various foods are needed to intervene and possibly halt the rising proportion of overweight children.
1
CHAPTER ONE
Introduction
Childhood is a dynamic period in human life during which rapid physical growth
creates an extraordinary demand for energy and nutrients. The physical, developmental, and social changes that occur in childhood can profoundly affect eating behaviors and nutritional health. Failure to consume a healthy diet during this time can potentially affect
children’s growth and cognitive development and constitutes a risk for immediate health
problems as well as for chronic diseases in later life (Nicklas & Hayes, 2008). In view of
evidence that many children in Western countries are overweight or obese and have a
poor diet, the eating behavior of these young people has become an increasing public
health concern (LaRowe, Moeller, & Adams, 2007).
Childhood offers a unique opportunity to positively influence the adoption or
maintenance of healthy eating behavior that could be sustained throughout adulthood.
However, an understanding of the factors influencing children’s eating behavior is a
prerequisite. In this study, influences on school-age children’s milk and soft drink intake
were investigated using the Theory of Planned Behavior (TPB) (Ajzen, 1988, 1991). The influence of gender, ethnicity, and body mass index (BMI) on the relationship among behavioral beliefs, normative beliefs, control beliefs, attitude toward the behaviors, subjective norm, perceived behavioral control, behavioral intention, and milk and soft drink intake were examined. This chapter includes the problem, the background and significance, the research questions and the theoretical framework.
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Problem
Compared to meeting the Dietary Reference Intakes (DRIs) and diets characterized by variety, moderation, and proportionality, the food choices of children in
the U.S. do not meet the national recommendations (Nicklas & Hayes, 2008). Over the
past three decades, major changes have taken place in the beverage consumption patterns
of American children (Nicklas & Hayes, 2008). Specifically, insufficient intake of
calcium-containing foods such as milk, and excess carbohydrate consumption, mainly of
soft drinks, are critical concerns related to childhood obesity (Ariza, Chen, Binns, &
Christoffel, 2004; Ludwig, Peterson, & Gortmaker, 2001; Nicklas, Baranowski, Cullen,
& Berenson, 2001; Nicklas & Hayes, 2008).
Eating behaviors formed during childhood have immediate as well as potentially
lifelong effects on health. Over the past three decades, changes in children’s food intake,
specifically overconsumption of energy-dense, nutrient-poor foods and beverages have
raised concerns due to their possible link to overweight in children (Nicklas & Hayes,
2008). As overweight children become overweight adults, the diseases associated with obesity and health care costs are expected to increase (Wang & Dietz, 2002).
Consequently, there is an urgent need for American children to adopt and maintain healthy eating behaviors to become fit and healthy adults with low morbidity and adequate physical work capacity. This may be attained through nutrition education, physical fitness programs, and effective interventions for children. The design of interventions that yield desirable changes in behavior require a prior understanding of
children’s eating behavior and the factors that influence them. Despite considerable
research in the area of child health, there is a paucity of descriptive, theoretically-based
3
investigations to identify factors that influence eating behaviors, specifically milk and
soft drink intake of school-age children, the focus of the present study.
Background and Significance
Milk and soft drink intake among American children
The relationship between nutrition, maintenance of health, and development of chronic diseases has been well established. Despite the national initiatives to promote lifelong healthy eating behavior, the behavior patterns of American children point to a growing trend toward unhealthy lifestyles and practices and their overall dietary quality has been found to decrease as they grow into adulthood (Demory-Luce et al., 2004). This
is of great concern due to the rising prevalence of obesity and overweight and the
consequent obesity-related diseases in both adults and children (Ogden, Yanovski,
Carroll, & Flegal, 2007). These diseases result in around 300,000 deaths and account for
more than $100 billion per year treatment costs (Allison, Fontaine, Manson, Stevens, &
VanItallie, 1999; Blumenthal, 2001; Must et al., 1999).
As a result of the recommendations to decrease dietary fat, there has been an
increase in carbohydrate intake by children. In addition, it is believed that the type of
carbohydrates consumed by children have changed to those with a higher glycemic index, an indicator of the ease with which a carbohydrate is digested (Slyper, 2004). In the U.S.,
children’s daily food intakes are markedly high in added sugars, those eaten separately or
used as ingredients in processed or prepared foods and beverages such as white sugar,
brown sugar, raw sugar, corn syrup, high-fructose corn syrup that do not contribute to
intake of vitamins, minerals, or other essential nutrients (Sigman-Grant & Morita, 2003).
4
Soft drinks are a major source of added sugars and they constitute the primary
beverage leading to increase in carbohydrate intake among 2 to 17-year-old children
(Nicklas & Hayes, 2008). A soft drink is a soda made from carbonated water, added sugar, and flavors (Nestle, 2000). Diet sodas contain artificial sweeteners instead of sugar and are consumed to a lesser extent by children as compared to regular soda (French, Lin,
& Guthrie, 2003; Grimm, Harnack, & Story, 2004). Each 12-oz serving of carbonated sweetened soft drink contains the equivalent of 10 teaspoons of sugar (Murray et al.,
2004), 40 grams of added sugar and 160 Kcal (Nestle, 2000).
Trends in children’s and adolescents’ beverage consumption indicate the possibility
of soft drinks replacing more nutritious drinks such as fruit juices and milk (Ballew,
Kuester, & Gillespie, 2000; Bowman, 2002; Rampersaud, Bailey, & Kauwell, 2003).
Data from national dietary surveys indicate that within the latest decades there has been a
dramatic increase in soft drink consumption among children in the U.S. (Nielsen &
Popkin, 2004; Nielsen & Popkin, 2003; Nielsen, Siega-Riz, & Popkin, 2002; Rampersaud et al., 2003; Smiciklas-Wright, Mitchell, Mickle, Goldman, & Cook, 2003). In 20 years, soft drink consumption has increased 300% (Cavadini, Siega-Riz, & Popkin, 2000) and serving sizes have grown from approximately 6.5 oz in 1950 to 12 oz in the 60s and 20 oz by the end of the 90s (Murray et al., 2004).
Carbonated soft drink consumption has been found to increase with age, with a
striking increase beginning around age 8 years. Between 1977 and 1998, soft drink
consumption increased 48% among 6 to 17-year-olds (French et al., 2003). Soft drinks account for 8.5% of children’s daily energy intake in the U.S. (Adair & Popkin, 2005).
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Among school-age children, 56% to 85% drink at least one soft drink daily (Rampersaud et al., 2003).
From 1965 to 1996, lower fat milk has replaced higher fat milk but total consumption of milk has dropped significantly by 36% among children and adolescents
(Cavadini et al., 2000; Rajeshwari, Yang, Nicklas, & Berenson, 2005). Between 1977 and
2001, daily milk consumption among 2-to-18-year-olds has decreased from 3.46 servings to 2.75 servings (Nielsen & Popkin, 2004). As milk intake decreased, soft drinks have become children’s preferred choice of beverage, with their consumption more than tripling as children move from third to eighth grades (Lytle, Seifert, Greenstein, &
McGovern, 2000).
The decrease in milk consumption has occurred among both school-aged girls and boys (Fiorito, Mitchell, Smiciklas-Wright, & Birch, 2006). Concomitantly, soft drink consumption almost doubled (Bowman, 2002), a phenomenon that has been positively associated with higher caloric intakes (Adair & Popkin, 2005). In a national sample of
Americans ages 2-60 years, the biggest decrease in milk consumption from 13.2% in
1977 to 8.3% in 2001 occurred in the 2-to 18-year age group (Nielsen & Popkin, 2004).
For this same age group during the same time period, soft drink intake increased from
3.0% to 6.9% and milk portion sizes decreased from 15.4 oz in 1977 to 13.6 oz in 1996
(Nielsen & Popkin, 2004). Due to the cross-sectional nature of the available studies, it is still unclear whether milk intake has become less popular or if soft drinks have been substituted for milk.
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Effects of milk and soft drink intake on children’s health
Milk. Besides growth and intellectual development, unhealthy eating behavior can
increase a child’s risk for a number of immediate health problems (Nicklas & Hayes,
2008). In addition to essential nutrients such as phosphorus, riboflavin, vitamin B12,
protein and vitamin A, dairy products contain substantial amounts of Vitamin D and
calcium. Milk is the main source of calcium in the American diet (Nicklas, 2003).
Because of its importance in several metabolic processes such as bone remodeling,
vascular function, muscular contraction, and others, inadequate calcium intake is a
serious public health issue. Furthermore, there have been reports about the beneficial role
of adequate dairy foods and calcium intake in weight maintenance and moderating body
fat in children (Skinner, Bounds, Carruth, & Ziegler, 2003; Novotny, Daida, Acharya,
Grove, & Vogt, 2004), insulin resistance (Heaney, Davies, & Barger-Lux, 2002; Pereira
et al., 2002), and some chronic diseases of older age such as hypertension (Huth,
DiRienzo, & Miller, 2006; Resnick et al., 2000), some cancers (Grant, 2002) and
osteoporosis (Flynn, 2003).
In diets low in dairy products, diminished calcium intake prevents the
accumulation of maximal peak bone mass during early adolescence, a critical time in life
(More, 2008). Bones contain almost 100% of calcium in the human body and nearly 40% of peak bone mass is built up during adolescence (More, 2008). A 5% to 10% deficit in
peak bone mass has been reported to increase lifetime incidence of hip fracture by 50%, a
problem that can be prevented by ensuring adequate intake of calcium among
preadolescents and adolescents (Wyshak, 2000). Inadequate dietary calcium intake,
together with inactivity, may hinder maximal skeletal growth and bone mineralization,
7 increasing risk of developing osteoporosis in later life (Whiting et al., 2004).
Furthermore, in both clinical and epidemiologic studies, higher intakes of calcium and dairy products have been associated with lower body fat and weight in children and adults (Carruth & Skinner, 2001; Davies et al., 2000; Heaney et al., 2002; Zemel, Shi,
Greer, Dirienzo, & Zemel, 2000).
Soft drinks. In addition to being associated with multiple health problems such as obesity (Ludwig et al., 2001), damage of the gastric mucosa (Kapicioglu et al., 1998), decrease in esophageal pH (Rubinstein, Hauge, Sommer, & Mortensen, 1993), duodenal acidification and ulceration (McCloy, Greenberg, & Baron, 1984), frequent intake of carbonated soft drinks has been associated with dental caries in children (Mariri et al.,
2003) due to their high sugar content and acidity causing enamel erosion (Heller, Burt, &
Eklund, 2001). Despite considerable progress made in the U.S., the 2000 United States
Surgeon General’s report indicates that 45% of children ages 5 to 17 still have dental caries (Allukian, 2000).
Besides calories, carbonated soft drinks offer minimal or no nutritional value.
There have been negative associations between intakes of carbonated soft drinks and intakes of essential micronutrients such as calcium, riboflavin, vitamins A, C, and D, phosphorus, folate, and magnesium in preschool and school-age children and adolescents
(Bowman, 2002). Furthermore, soft drinks are the greatest source of caffeine in children’s diets, which is of concern due to the potential for addiction (Keast & Riddell,
2007).
In addition to contributing to a reduction in the quality of children’s diets and their chances of achieving nutritional adequacy, soft drink consumption is a significant
8
contributor to total caloric intake (French et al., 2003; Ludwig et al., 2001). After
adjusting for anthropometric, demographic, dietary, and lifestyle variables in a
longitudinal study, each 12-oz daily serving of sugared soft drink was associated with a
0.18-point increase in children’s BMI and 60% increase in risk of obesity (Ludwig et al.,
2001). In a more controlled clinical study in Denmark, similar results were found for an
association between sweetened beverage intake and considerable weight gain (Raben,
Vasilaras, Moller, & Astrup, 2002). Compared to normal weight children, overweight
children are more likely to become obese adults (Magarey, Daniels, Boulton, &
Cockington, 2003), which increases long-term risk of CHD, hypertension, type 2 diabetes
(Ferraro, Thorpe, & Wilkinson, 2003), gallbladder disease, osteoarthritis, and some forms of cancer (Bray, 2003).
In addition to other factors, high soft drink consumption is thought to be contributing to the increasing prevalence of overweight and obesity among children
(Malik, Schulze, & Hu, 2006) possibly due to excessive caloric content, as soft drinks
have been found to contribute an additional intake of 188 Kcal/day in consumers
compared to nonconsumers (St-Onge, Keller, & Heymsfield, 2003). Furthermore, these
beverages are ingested in addition to, and not as a replacement for, other dietary products,
contributing to a higher caloric intake (Bellisle & Rolland-Cachera, 2001).
Several other mechanisms have been suggested to explain the link between soft
drink intake as a high-glycemic-index carbohydrate and obesity: (1) decreased milk intake concurrent with the rise in soft drink consumption; (2) high-glycemic index
carbohydrates lead to postprandial hyperinsulinemia, which may result in excessive weight gain; (3) decreased resting energy expenditure with beverages of high-glycemic
9
index carbohydrates compared with that of mixed-nutrients, such as milk that contains fat, protein, and carbohydrate; or (4) beverages with high-glycemic-index promote increased food intake due to decreased satiety and fullness sensation (Slyper, 2004; St-
Onge et al., 2003).
Purpose
Many lifestyle habits, such as eating behavior, that affect risk factors for chronic diseases have their environmental and behavioral roots in childhood (Joseph & Kramer, 1996). Furthermore, in view of the seriousness of the health consequences of children’s low milk consumption and increased soft drink intake and due to scarcity of the literature on factors influencing these behaviors, this study aimed at identifying factors that influence school-age children’s milk and soft drink intake using the TPB. The purposes of this study were to: (1) determine influences on school-age children’s milk and soft drink intake and (2) determine the effect of gender, ethnicity, and body mass index (BMI) on behavioral beliefs, normative beliefs, control beliefs, attitude toward the behavior, subjective norm, perceived behavioral control, intention and behaviors about milk/soft drink intake in school-age children. In this study, the words soft drink, soda, and soda pop are used interchangeably.
Theoretical framework
Since Wicker’s (1969) conclusion that attitudes may not predict behavior, social
psychologists have worked on improving the predictive power of attitudes. Thereafter,
among the models used to predict and understand social behavior, the most widely used
ones have been the Theories of Reasoned Action (TRA) (Ajzen & Fishbein, 1980;
Fishbein & Ajzen, 1975) and Planned Behavior (Ajzen, 1988, 1991) which will be
10
guiding this study. The aim of both theories is to understand and predict one’s behavior
from other determinants (Ajzen & Fishbein, 1980). They assume that individuals are
“rational actors” who process information and are motivated to act on it (Ajzen &
Fishbein, 1980). Fishbein (1967) developed and first introduced the TRA in 1967 in an attempt to understand the relationship between attitudes and behavior. The TRA includes measures of attitude and social normative perceptions that determine behavioral intention, which, in turn affects behavior. Refer to Figure 1 for the theoretical model of
the TRA and the TPB.
Figure1 . Theoretical Model of the Theory of Reasoned Action and Theory of Planned Behavior
Behavioral beliefs Attitude toward and outcome the behavior evaluations
Normative beliefs and motivation to Subjective norm Behavioral Behavior comply intention
Control beliefs and Perceived perceived power behavioral control
Note. The shaded sections depict the TRA and the entire model depicts the TPB.
The TRA and the TPB assume that behavioral intention is the main direct
determinant of behavior. Thus the usefulness of this theory in explaining behavior
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depends on the extent to which the concerned behavior is under volitional control, i.e.
situations in which individuals have a large degree of control and thus can decide
willingly to perform or not to perform the behavior (Ajzen, 1991; Montaño & Kasprzyk,
2002). The theory has performed poorly in explaining behaviors over which individuals
have incomplete volitional control i.e. under conditions where there are constraints on
action, rendering intention as insufficient to predict behavior. An example would be in
the case of a person who has high motivation to eat healthy foods (behavior) but does not
actually do so due to environmental conditions such as cost and availability of healthy
foods. A possible reason for this may be that there are multiple factors influencing one’s intention, which complicates prediction of behavior from intention.
According to Ajzen (1991), most behaviors are found along a continuum extending
from total control to complete lack of control. When faced with no constraints in
adopting a certain behavior, an individual would have total control. In contrast, if
resources and skills that are prerequisites to adoption of a behavior are lacking or
unavailable, an individual would have lack of control. Thus, to address incomplete
volitional control, Ajzen (1991) proposed the TPB that includes the concept of perceived behavioral control.
The TPB is a microlevel theory derived from expectancy-value theory, meaning
that people are likely to take action if they perceive that the action will lead to expected
outcomes or anticipated consequences they value or desire. As such, children may choose
to drink milk to maximize positive outcomes such as maintenance of health and body
weight and to minimize negative outcomes. As seen in the theoretical model in Figure 1, the TPB postulates that behavior is predicted indirectly from perceived behavioral control
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through the mediating effect of behavioral intention, as well as directly from behavioral
intention and perceived behavioral control (Ajzen, 1991). Behavioral intentions
determine perceived likelihood of performing a certain behavior (Ajzen & Fishbein,
1980). They are thought to represent the motivational factors influencing behavioral
performance i.e. they are indications of how hard people are willing to try to perform a
behavior. In general, the stronger one’s intention to do a certain behavior, the more
probable would be its performance, provided the behavior is under volitional control
(Ajzen, 1991).
Perceived behavioral control reflects one’s perception of how easy or difficult it is
to perform a certain behavior (Ajzen, 1991). It is assumed to reflect external factors such
as availability of time, money, or social support and internal factors such as ability, skills,
and information (Ajzen & Timko, 1986). Perceived behavioral control, as a predictor of
behavior, is most useful under two conditions. First, when the behavior being predicted is
not under complete volitional control and second, when perceptions of behavioral control
reflect actual control with some degree of accuracy (Ajzen & Madden, 1986). The
addition of perceived behavioral control is meant to add knowledge about the potential
constraints on performing an action as perceived by the actor, thus explaining failure of
intentions to always predict behavior (Armitage & Conner, 2001). Therefore, in cases when one’s level of volitional control hampers prediction of behavior from intention, perceived behavioral control is expected to (1) ease the implementation of behavioral intentions into behavior, and (2) directly predict behavior. Ajzen (1991) proposed the direct relationship between perceived behavioral control and behavior because of lack of evidence for the interactive effect of perceived behavioral control on the intention-
13 behavior relationship. He further explains that in cases where behavioral intentions alone account for small amounts of variance in behavior, possibly due to problems in volitional control, perceived behavioral control should independently predict behavior.
According to the TPB, behavioral intention can be explained by three conceptually independent determinants: attitude toward the behavior, subjective norm, and perceived behavioral control. Attitude toward the behavior refers to “the degree to which a person has a favorable or an unfavorable evaluation or appraisal of the behavior in question”
(Ajzen, 1991). Subjective norm refers to “the perceived social pressure to perform or not to perform the behavior” (Ajzen, 1991). Perceived behavioral control, as described above, reflects one’s perceived ease or difficulty of performing a certain behavior. It is assumed to represent past experience and expected obstacles. The relative contribution of the three determinants in predicting intention is shown to vary across behaviors and situations (Ajzen, 1991). For example, with a certain behavior, attitudes may have a significant effect on intentions, while with other behaviors attitudes and subjective norms may account for the variance in intentions, and in still others, all three predictors may have independent impacts.
According to the TPB, individuals have the following three salient beliefs that are the main determinants of their intentions and actions: (1) behavioral beliefs, which are beliefs about the likely outcomes of the behavior and the evaluations of these outcomes;
(2) normative beliefs that are beliefs about the normative expectations of others and motivation to comply with these expectations, and (3) control beliefs about the presence of factors facilitating or impeding performance of the behavior and the perceived power of these factors in helping behavioral performance. In combination, behavioral beliefs
14
give rise to favorable or unfavorable attitude toward the behavior, normative beliefs
result in perceived social pressure or subjective norm, and control beliefs lead to
perceived behavioral control (Ajzen, 1991).
In summary, attitude toward the behavior, subjective norm, and perceived
behavioral control result in the development of a behavioral intention. According to
Ajzen (1991), the more favorable the attitude, subjective norm, and perceived behavioral
control toward a behavior, i.e. when people evaluate a behavior positively, believe that
important others think they should perform it, and perceive of having control over it, the
stronger should be their intention to engage in that behavior. Intention is considered the
direct antecedent of behavior because, given an adequate degree of actual control over a certain behavior, individuals are expected to carry out their intentions. However, given the fact that many behaviors are not under one’s complete volitional control, in addition to intention, perceived behavioral control can be considered.
The TPB is chosen as a framework to guide this study for two reasons. First, the
TPB includes the social influence which is very pertinent to this study because eating behaviors take place in a social context where other eaters such as parents, siblings, and peers act as models and children’s observations of these models’ eating behavior influence their own preferences and eating behaviors (Birch & Fisher, 1998). Second, the
TPB provides an opportunity to further investigate the salient beliefs underlying attitudes,
subjective norms, and perceived behavioral control, which may enable further
understanding of factors influencing children’s milk and soft drink intake, which is vital
for future behavior change initiatives.
15
Study concepts
The relationships among the concepts of this study are illustrated in Figure 2 and the substruction is diagramed in Figure 3. Contrary to the TPB, in this study a direct relationship between perceived behavioral control and both milk and soda drinking behaviors was tested. The rationale for this modification is that some children have no control over their milk and soft drink choices and thus the relationship between perceived behavioral control and the behaviors through intention may not hold true. In addition to
the concepts of the TPB, the influence of three covariates: gender, ethnicity, and BMI on
the theoretical constructs were investigated in this study. Gender and ethnicity were
selected because previous studies about attitudes and eating and physical activity behaviors using the TPB with children and adolescents have found gender differences in the predictors (Backman, Haddad, Lee, Johnston, & Hodgkin, 2002; Berg, Jonsson, &
Conner, 2000; Craig, Goldberg, & Dietz, 1996). The association between BMI and food choice has not been extensively investigated in children. Therefore, in this study, we wanted to investigate this relationship.
16
Figure 2. Theoretical Model of the Study Based on the Theory of Planned Behavior
Q6 Gender Q7 Q8 Ethnicity BMI Q6 Q7 Attitude Q6 Q3 Q8 Behavioral toward the Q2 Q7 beliefs behavior Q8 Behavior Q4 Intention to Q1 Q2 Daily milk Normative Subjective drink milk intake beliefs norm and soft drink Daily soft Q2 drink Q5 Perceived Control behavioral Q1 beliefs control
Figure 3. Substruction diagram of the study 17
18
Definition of terms
As depicted in the theoretical model in Figure 2, in this study there are two
behaviors to be investigated: daily milk intake and daily soft drink intake. Consequently,
in the following section, the definitions of each concept will refer to both behaviors.
Behavior. Behavior is actions taken by individuals. Based on United States
Department of Agriculture’s (USDA) recommendations, daily milk intake is defined as
drinking three cups of regular milk per day (USDA, 2005). Daily soft drink intake is the
amount of regular (not including diet) carbonated beverages ingested. Both behaviors
were measured by having the participants indicate the amount of milk and soda pop they
drink in the 24-hour dietary recall.
Intention to drink milk and soft drink. This variable refers to a person’s perceived
likelihood of drinking three cups of milk and regular carbonated beverages daily. These
concepts were measured by the Intention to drink milk and Intention to drink soda pop
scales.
Attitude toward the behavior. In this study, attitude toward the behavior refers to a
person’s feeling of favorableness or unfavorableness toward drinking milk and soft drink
daily. These concepts were measured by the Attitude toward milk intake and Attitude
toward soda pop intake scales.
Behavioral beliefs. Behavioral beliefs refer to a person’s conviction that drinking
milk and soft drink daily will be associated with certain positive or negative outcomes
and one’s evaluation of these outcomes. These concepts were measured by the
Behavioral beliefs about milk and Behavioral beliefs about soda pop scales.
19
Subjective norm. Subjective norm refers to a person’s perception of social pressure or approval to drink 3 cups of milk and soft drink daily. These concepts were measured by the Subjective norm to milk intake and Subjective norm to soda pop intake scales.
Normative beliefs. Normative beliefs refer to the likelihood that certain important people with whom the individual is motivated to comply would approve or disapprove of that person’s drinking milk and soft drink daily. These concepts were measured by the
Normative beliefs about milk intake and Normative beliefs about soda pop intake scales.
Perceived behavioral control. Perceived behavioral control is a reflection of how easy or difficult it is for someone to drink milk or soft drink daily. These concepts were measured by the Perceived behavioral control over milk intake and the Perceived behavioral control over soda pop intake scales.
Control beliefs. Control beliefs refer to the presence of particular factors and their power to make easy or difficult for a person to drink milk and soft drink daily. These will be measured by Control beliefs about milk intake and Control beliefs about soda pop intake scales.
Gender. Gender refers to the biological sex of the participants and was indicated by each participant on the demographic characteristics form.
Ethnicity. Ethnicity is one’s affiliation in terms of language, customs, and beliefs with a racial or cultural group. It will be indicated by each participant on the demographic characteristics form.
Body mass index. BMI is a measure of adiposity. It was operationalized using the free CDC child and teen calculator (CDC, 2006). In this study, BMI-for-age percentile
20 was categorized as follows: between 5th and < 85th percentile (healthy weight), between
th th 85 and < 95 percentile (at risk of overweight), ≥ 95th percentile (overweight). Research questions
Based on Figure 2 the theoretical model of this study, the following research questions were investigated and analyzed in this study.
1. Does intention about milk/soft drink intake and perceived behavioral control
influence behavior about milk/soft drink intake in school-age children? (Q1)
2. Does attitude toward the behavior, subjective norm, and perceived behavioral
control influence intention about milk/soft drink intake in school-age children?
(Q2)
3. Do behavioral beliefs about milk/soft drinks influence attitude toward milk/soft
drink intake in school-age children? (Q3)
4. Do normative beliefs about milk/soft drinks influence subjective norm about
milk/soft drink intake in school-age children? (Q4)
5. Do control beliefs about milk/soft drinks influence perceived behavioral control
about milk/soft drink intake in school-age children? (Q5)
6. Are there differences by gender on behavioral beliefs, normative beliefs, control
beliefs, attitude, subjective norms, perceived behavioral control, intention and
behavior about milk/soft drink intake in school-age children? (Q6)
7. Are there differences by ethnicity on behavioral beliefs, normative beliefs, control
beliefs, attitude toward the behavior, subjective norm, perceived behavioral
control, intention and behavior about milk/soft drink intake in school-age
children? (Q7)
21
8. Are there differences by BMI on behavioral beliefs, normative beliefs, control
beliefs, attitude toward the behavior, subjective norm, perceived behavioral
control, intention and behavior about milk/soft drink intake in school-age
children? (Q8)
Significance of the study
In order to fulfill its goal of providing health care for clients, the main aim of nursing science is to generate scientific knowledge to guide nursing practice (Hinshaw,
1989). The significance of this study is in its potential contribution to the advancement of the discipline of nursing through generation of knowledge for both science and practice.
The concepts of this study fit with the perspective of nursing and its metaparadigm. The concept of person includes the school-age children whose eating behavior is of concern in this study. Environment entails internal stimuli such as the factors influencing children’s milk and soft drink intake, and external stimuli in the social context in which eating behaviors are influenced and shaped. Health is the state that ultimately results from the children’s milk and soft drink intake. Nurses are concerned with understanding factors that influence children’s eating behavior in order to promote healthy eating behavior among them.
Nurses, as health professionals, have a responsibility for health education and behavior change interventions. Knowledge generated from this study will be pertinent to the nursing science as it falls under one of the 11 research priorities for the 21st century outlined in The American Nurses’ Association policy statement on nursing research which is: “Minimizing or preventing behaviorally and environmentally induced health problems that compromise the quality of life and reduce productivity” (ANA, 1985, p. 3-
22
4). By investigating the fundamental psychosocial mechanisms underlying children’s
acquisition of health promoting behavior, information gathered from this study will aid in
maintenance of healthy lifestyles for children.
The design of interventions that generate desirable changes in health behavior can
best be implemented with an understanding of the theories of behavioral change and their
proper use in practice (Glanz, Rimer, & Lewis, 2002). Knowledge generated from this
theoretically-based study will add to the limited body of knowledge about the
phenomenon of children’s eating behavior, which can aid them and other health
professionals to initially understand what factors influence children to drink milk and soft
drinks. Subsequently, this will contribute to the design and implementation of tailored programs to meet the health needs of children specifically by promoting healthy eating behavior, such as drinking milk and minimizing soft drink intake among children, at the individual or community level, to possibly halt the obesity epidemic and ultimately improve their health status.
23
CHAPTER TWO
Review of the Literature
This study is guided by a value expectancy theory, the TPB, and it was designed
within a cognitive developmental context. This chapter starts with an overview of
childhood obesity and dietary recommendations and guidelines to improve eating
behavior among children in the US. This section will be followed by an explanation of children’s health beliefs based on their cognitive developmental level. Finally, a review of the literature about factors influencing children’s milk drinking behavior and soft drink intake will be presented. Conceptual, theoretical, and methodological issues will also be addressed.
Human food consumption has been found to vary considerably by age. Factors affecting eating patterns of school-age children are different than factors affecting eating patterns of adolescents, which, in turn, are different than those of adults. One possible reason for these differences is because children have to rely more on their parents for food, whereas adolescents and adults are independent. Because there are few studies about food choices of school-age children (Baranowski, Cullen, & Baranowski, 1999),
the literature review also will include studies conducted with adolescents.
Overview of Childhood Overweight and Obesity
Historical nutrient deficiencies in the U. S. have been replaced by excesses such
as in the case of soft drinks and calories and imbalances of some other food components
(e.g. insufficient calcium) (Nicklas & Hayes, 2008). Consequently, according to the
United States Department of Health and Human Services (USDHHS), there has been an
alarming increase in the number of overweight and obese children, rendering obesity an
24
important public health problem (USDHHS, 2000). The age-adjusted prevalence of
obesity has doubled from 1976-1980 to 1988-1994 for children in the 6- to 11-year-old
age group (Ogden, Flegal, Carroll, & Johnson, 2002), and the prevalence of overweight in the same age group has continued to significantly increase from 1999 to 2004 (Ogden et al., 2006). Because of the serious sequelae of obesity and the alarming increase in prevalence, an overview of obesity is presented in this section.
The World Health Organization (WHO) has defined obesity as “an accumulation of excess body fat, to the extent that health might be impaired” (Clement & Ferre, 2003, p. 722). Because it is difficult to measure body fat directly, obesity often is defined as
excess body weight rather than as excess fat (Ogden et al., 2007). According to U.S.
Centers for Disease Control and Prevention (CDC), a BMI-for-age between 85th and
95th percentile for age and sex, which corresponds to a BMI of 25 kg/m2 and above, is considered “at risk of overweight” and a BMI at or above the 95th percentile, which corresponds to a BMI of at least 30 kg/m2, is considered overweight or obese (CDC,
2006).
The degree of body fat mass in children depends on ethnic background, gender,
age, and developmental stage (Rosner, Prineas, Loggie, & Daniels, 1998). Fat mass
increases from 14% of body weight at birth to around 25% at the age of 6 months, then
progressively decreases until the age of 6 to 7 years. Eventually the relative fat mass increases until maturity, reflecting individual differences in fat mass (Maffeis, 1999).
Consequently, the BMI charts available for children take into account age and gender
(Flegal, Wei, & Ogden, 2002).
25
Energy balance to maintain the body’s steady-state can be regulated at the level of
food intake or energy output. Obesity develops when there is a discrepancy between
energy intake and energy output, disrupting the original steady-state, which, after a period of positive energy balance, leads to the development of a new steady-state at a
higher level with an increase in body fat store (Wabitsch, 2000). In general, obesity
involves an increase in both the number and the size of adipocytes and different types of
obesity (android or gynecoid) can be determined based on the location of adipose tissue
deposition in the body (Spiegelman & Flier, 2001).
In a survey of 8165 children and adolescents from two through 19 years of age
with weight and height measurements obtained in 2003-2004 and 2005-2006 as part of
the National Health and Nutrition Examination Survey (NHANES), 11.3% were at or
above the 97th percentile (obese) of the BMI-for-age growth charts, 16.3 were at or above the 95th percentile (obese), and 31.9% were at or above the 85th percentile (overweight)
(Ogden, Carroll, & Flegal, 2008). Specifically among 10-year-olds, the percentage of
overweight had increased significantly (p < .0001) from 13% in 1973-1974 to 39% in
1993-1994 and the percentage of obesity in the same age group had also increased
significantly (p < .0001) from 4% in 1973-1974 to 21% in 1993-1994 (Ogden et al.,
2002). Trend analysis indicated no significant changes in the prevalence of high BMI-for-
age among children and adolescents between 2003-2004 and 2005-2006 and no
significant trends between 1999 and 2006 (Ogden et al., 2008).
During the last two decades, being overweight has been more common among
ethnic minorities, with Blacks and Mexican Americans experiencing greater increases
than whites (Ogden et al., 2002). Similarly, during the current decade, prevalence of
26
being overweight among non-Hispanic white girls aged 6-19 years has been significantly
lower than that of non-Hispanic black and Mexican American girls (Hedley et al., 2004).
For boys of the same age group, being overweight has been significantly more prevalent among Mexican Americans than in non-Hispanic white and black boys (Hedley et al.,
2004).
Obese children are more prone to experience psychological or psychiatric problems than their non-obese counterparts (Reilly et al., 2003). In many children, being
overweight or obese precedes low self-esteem, suggesting a causal relationship. In a
study in which relationships between BMI and self-esteem across the elementary school years were investigated, an increasingly strong association between lower self-esteem and higher BMI was found (Hesketh, Wake, & Waters, 2004). Also prejudice against obesity starts in children as young as 6 years (Kolotkin, Meter, & Williams, 2001).
Many studies have consistently shown associations between obesity and
cardiovascular risk factors such as high blood pressure; dyslipidemia; abnormalities in
left ventricular mass and/or function; abnormalities in endothelial function; and
hyperinsulinemia and/or insulin resistance (Berenson et al., 1998; Freedman, Khan,
Dietz, Srinivasan, & Berenson, 2001; Freedman, Dietz, Srinivasan, & Berenson, 1999;
Reilly et al., 2003). Ten percent of a sample (n = 3599) of 5 to10 year olds in the U.S. were overweight, with a significant risk for raised diastolic blood pressure (OR 2.4), raised systolic blood pressure (OR 4.5), raised low-density lipoprotein (LDL) cholesterol
(OR 3.0), decreased high-density lipoprotein (HDL) cholesterol (OR -3.4), raised
triglycerides (OR 7.1), and high fasting insulin concentrations (OR 12.1) (Freedman et
27
al., 1999). Fifty-eight percent of the total sample had at least one of these cardiovascular
risk factors (Freedman et al., 1999).
Several studies have also described associations between obesity and asthma in childhood (Castro-Rodriguez, Holberg, Morgan, Wright, & Martinez, 2001; Sulit,
Storfer-Isser, Rosen, Kirchner, & Redline, 2005). In a longitudinal study of children (n=
1246) participating in a birth cohort, it was reported that becoming obese increased the
risk of developing asthmatic symptoms in girls who were originally not known to be
asthmatic (Castro-Rodriguez et al., 2001).
Childhood obesity has also been found to be associated with type 1 diabetes
(Hypponen, Virtanen, Kenward, Knip, & Akerblom, 2000), low grade systemic
inflammation as indicated by elevated serum C-reactive protein concentration (Visser,
Bouter, McQuillan, Wener, & Harris, 2001), sleep apnea (Dietz, 1998), structural abnormalities of the foot in prepubescent children (Riddiford-Harland, Steele, & Storlien,
2000), reduced quality of life (Williams, Wake, Hesketh, Maher, & Waters, 2005), and poor academic performance (Taras & Potts-Datema, 2005).
From 1979-1981 to 1997-1999, hospitalizations for obesity-related diseases
among 6- to 17-year-olds have increased considerably, leading to significant increases in
costs (Wang & Dietz, 2002). Discharge diagnoses with obesity-related diseases such as
diabetes have almost doubled from 1.43% to 2.36%, gallbladder diseases have tripled
reaching 0.59%, and sleep apnea has increased fivefold from 0.14% to 0.75%. Asthma
and some mental disorders were the most common principal diagnoses when obesity was
listed as a secondary diagnosis. In this same period, annual hospital costs related to
obesity among 6- to 17-year-olds have increased more than threefold (Wang & Dietz,
28
2002). The direct medical costs of obesity in the United States have recently been
estimated as more than $92 billion in 2002 dollars (Finkelstein, Fiebelkorn, & Wang,
2003).
Dietary Recommendations and Guidelines for Children
Over the past decade, health professionals have begun to address the challenge of
promoting healthful dietary behavior to reduce the risk of chronic diseases. The
recommendations from national health organizations have become more focused,
identifying dietary excesses of caloric intake, physical activity patterns, and prevention of
chronic diseases among Americans. In this regard, the following is the position statement of the American Dietetic Association (ADA): “It is the position of the American Dietetic
Association that children ages 2 to 11 years should achieve optimal physical and
cognitive development, attain a healthy weight, enjoy food, and reduce risk of chronic
disease through appropriate eating habits and participation in regular physical activity”
(Nicklas & Johnson, 2004).
Currently, more than ten scientific organizations have established dietary
recommendations and guidelines for children over two year of age. In 2002, the
Recommended Dietary Allowances (RDAs) were updated and the Dietary Reference
Intakes (DRIs) for energy, carbohydrates including added sugars, protein, amino acids,
fiber, fat, fatty acids, and cholesterol were presented by the Institute of Medicine’s Food
and Nutrition Board. The acceptable macronutrient distribution ranges (AMDR) as a
percent of energy intake are as follows: carbohydrates 45% - 65%, fat 25% - 35% for children ages 4 to 18 years, and protein 5% - 20% for young children 1 to 3 years of age and 10% -30% for older children 4 to 18 years of age (Nicklas & Johnson, 2004).
29
Major sources of added sugars are soft drinks, fruit drinks, pastries, candy, and other sweets. The DRIs did not set an amount for daily intake of added sugars for a healthy diet for children; however, it was recommended that they not exceed 25% of total calories consumed (Nicklas & Hayes, 2008). This amount was based on findings that intakes of added sugars exceeding 25% of total energy were coupled with decreased intakes of key micronutrients, predominantly calcium. From 1988 to 1994, 21% of 9 to
13-year-old children had added sugar consumptions exceeding 25% of their total energy intakes ("Dietary reference intakes for energy, carbohydrate, fiber, fat, fatty acids, cholesterol, protein, and amino acids.," 2002).
In 1997, new DRIs for calcium were established by the National Academy of
Sciences. The DRI for calcium is 1300 mg for 9-18 year olds. The levels were raised 500 mg above the 1989 RDAs for calcium for 9-10 year olds and by 100 mg for 11-18 year olds based on findings that calcium intakes at levels higher than the 1989 RDA can increase bone mineral density in children (Chan, Hoffman, & McMurry, 1995; Johnston et al., 1992) decreasing their risk of developing osteoporosis later in life (Whiting et al.,
2004). However, concomitant with declines in milk intakes, calcium intakes have also dropped and are lower than recommended AIs (Cavadini et al., 2000; French et al., 2003;
Kranz, Lin, & Wagstaff, 2007).
The U.S. Department of Agriculture (USDA) Food Guide Pyramid is a nutrition education tool that was designed to help Americans eat more healthy diets (USDA,
1992). It was first introduced in 1992 as a guide to translate the nutrition recommendations of the Dietary Guidelines for Americans into types and amounts of food to eat daily. However, due to difficulty in putting the nutrition messages into
30
practice, The Food Guide Pyramid underwent a process of review and in 2005
MyPyramid was released symbolizing a personalized approach to healthy eating and
physical activity for Americans 2 years of age and older (USDA, 2005). It presents the
following concepts for maintenance of a good health: (1) Activity as a reminder of
importance of physical activity; (2) Moderation by limiting the consumption of foods
high in solid fats and added sugars; (3) Proportionality signifying eating greater amounts
of foods from the groups placed lower in the pyramid such as grains, vegetables, and
fruits and (4) Variety i.e. eating foods from all the five different food groups (USDA,
2005). For an estimate of what and how much one needs to eat from each food group, one
can enter one’s age, sex, and activity level in the MyPyramid Plan box to get results.
In another federal initiative, Healthy People 2010 presents 10 Leading Health
Indicators which reflect the major health concerns in the United States at the beginning of
the 21st century. Each health indicator has one or more objectives designed to guide
health promotion and disease prevention policy and programs at the federal, state, and
local levels in order to improve the health of Americans by the year 2010 (USDHHS,
2000). Overweight and obesity is one of the 10 leading health indicators. Among the
nutrition objectives, there are specific ones for consumption of calcium, fruits,
vegetables, grains, and saturated fat and quality snacks. The dietary guidelines mentioned
above are consistent with the dietary recommendations of the main health promotion
organizations such as the National Research Council, the National Cholesterol Education
Program, National Institutes of Health, the National Cancer Institute, the American
Cancer Society, and the American Heart Association. In addition to these initiatives, the
U. S. national health promotion and disease prevention objectives recommend that all
31 schools provide nutrition education from preschool through 12th grade ("Guidelines for school health programs to promote lifelong healthy eating," 1997).
Cognitive development
School-age children’s cognitive development
The traditional Piagetian view of child development is that of a biological stage theory, in which the child progresses linearly through four predictable stages based on cognitive structures: sensorimotor, preoperations, concrete operations, and formal operations (Phillips, 1975). Piaget has explained cognitive structures as patterns of physical or mental action underlying particular acts of intelligence that correspond to stages of child development. Through observations, Piaget studied children’s intrinsic abilities to think and learn and described this progression of cognitive development. This study will include 10 to 11 year old children; therefore, the design will be based on the characteristics of the concrete operational stage (7-11 years of age).
According to Piaget, true thinking begins in the third stage of cognitive development with concrete operations around 7 to 11 years of age. The cognitive structure during the concrete operational stage is logical but depends on concrete referents. Piaget characterizes this period as one in which there is a relationship between thinking and symbolic logic, where children can do “groupings” of “concrete operations
(Phillips, 1975). He further mentions the presence of egocentrism in reasoning and explains three models for the use of the term “because” by children: (1) causal explanation which involves cause and effect relationships between two facts, (2) psychological/motivational which entails cause and effect relationships between an
32 intention and an act, and (3) logical implication which involves reason and consequence relationships between two ideas or judgments (Phillips, 1975).
By age 7 or 8, the average child makes a distinction between psychological and causal explanations but has trouble with logical implications, often resorting to psychological explanations. At around 9 years of age, full fledged logical justifications are present. A possible reason for this is that children, at this age, are able to impose direction and order on their thinking (Phillips, 1975). Despite being interested in the development of operational knowledge, Piaget also talked about social knowledge as equally important. Neo-Piagetians also have emphasized the strong influence of social- emotional context and cultural meanings on children’s cognitive development (Suizzo,
2000).
Intentions. Despite the fact that attributions of intention are basic to understanding of human behavior, there is lack of research on children’s understanding of intention, specifically that of school-age children. Consequently, in the following section, the available data will be presented which also includes younger age-groups.
Rather than focusing on children’s understanding of intentions, most research on children’s knowledge about intentions has been conducted on their use or nonuse of intention in making moral judgments. Research has highly relied on Piaget’s (1932) finding that younger children differ from older ones and adults in their ability to distinguish between a wrongful act and the person’s intentions when assessing blame.
However, more recently, rather than drawing inferences from research on moral judgments, researchers have tried to investigate children’s understanding of intentions
33
more directly. Children as young as 4 to 5 years old have been found to possess an early
understanding of intention closely linked with action (Baird & Moses, 2001).
In studies assessing when children begin to understand intentions represented in
purposive, goal-directed behaviors, children as young as 3 and 4 years old were presented
with stories in which the characters’ intentions differed from their desires and the
outcomes of their efforts to carry out their intentions. Children between 3 ½ and 4 years
of age could, at a beginning level, differentiate among intention, desire and outcome
(Feinfield, Lee, Flavell, Green, & Flavell, 1999).
By age 4 or 5, children are able to clearly distinguish intentions from desires or
preferences and from the outcomes of intentional acts (Moses, 1993). They also become
aware of psychological determinants of behavior other than intentions such as emotions,
motives, knowledge, beliefs, and personality traits (Flavell, 1999). Children as young as 3
and 4 years old also have been found to differentiate psychological states like beliefs and
desires from biological processes like reflexes, and physical forces as possible
determinants of human actions (Schult & Wellman, 1997). In another study conducted
with older children, a story-book task was administered to four to 11-year-olds to find out
about their understanding of three facets of intention: trying, not-trying, and trying-not
(Barriault, 2003). A developmental effect was seen with a slow increase in children’s understanding of intention that plateaued from 8 to 10 years of age (Barriault, 2003). A
possible explanation from this study is that older children’s successful intention
attributions may be due to their understanding of goal-action consistencies and
inconsistencies (Barriault, 2003).
34
Cognitive development, health beliefs, and food choice
Research has concluded that children’s understandings of the concepts of health and illness change qualitatively with cognitive development in a manner following the progression from preoperations to concrete operations to formal operations suggested by
Piaget (Kalnins & Love, 1982). Their ability to classify and think causally begins in the early school years; however, their reasoning at this time is limited to concrete objects and particular experiences (Flavell, 1977; Inhelder & Piaget, 1958). In a study examining 5 to
11-year-olds (preoperational and concrete operational stage) children were found to rely heavily on dimensions of sweet versus nonsweet foods, and meal entrees versus drinks and breakfast foods. These findings suggest that, regardless of cognitive developmental level, children’s food classifications were influenced by perceptual, functional, and physical properties (Michela & Contento, 1984). It was further found that children in the concrete operations stage understood dimensions involving degree of processing of foods, their origin, and what happens to food in the body, implying that classification systems and understanding of nutrients became more sophisticated with cognitive developmental level. At this age, children also use more behavioral, concrete, and precise ideas to explain health (Mickalide, 1986).
Inborn preferences of human beings are modified by learning processes, which play a major role in the development of food preferences and food rejections (Rozin,
1989). Modification of food acceptance patterns in children have been explained through three different processes: (1) mere exposure to unknown food i.e. the repeated tasting of an unknown food reduces chances of rejecting it, a phenomenon known as neophobia, (2) social influences such as parents or peers, and (3) association of physiological
35
consequences of food taste (Birch & Fisher, 1998; Koivisto Hursti, 1999). These learning
processes result in cognitive structures and processes such as attitudes and beliefs toward
food and eating behavior which, in turn, affect food intake in later life (Pudel, 1986).
Cognitive-motivational processes begin to affect children’s food choices
beginning in the concrete operational stage (7-11 years of age) and continue into formal
operations (Contento, Michela, & Goldberg, 1988; Michela & Contento, 1986). Despite
these findings, the developmental studies that have been conducted have mostly
concentrated on the changes in children’s concept of illness or on changes in children’s
broad beliefs about health. Only a few developmental studies have been conducted about
school-age children’s health habits and beliefs. In one of the studies where the health
habits of children from grade 4 through 11 were assessed, girls were found to have
healthier food choices than boys and elementary school children also had healthier food
habits than older ones (Perry, Griffin, & Murray, 1985). In another study testing the
applicability of a cognitive-behavioral model of health behavior to children’s food
choices, those in the concrete operational stage tended to be in one of three groups
according to: health orientation in food choice, taste orientation, or multiple-motive orientation (Michela & Contento, 1986). The taste-oriented group had the poorest dietary quality. In addition to social/environmental influences on children’s food choices, children used a process of cognitive self-regulation. Their food choices were guided by their beliefs and values about the outcomes of their behaviors, and the level of cognitive development was related to the specific beliefs about food such that elementary schoolchildren at the concrete operational stage of cognitive development frequently
36
acted according to their motivations applicable to their food choice (Michela & Contento,
1986).
Using the “draw and write” techniques, findings indicate that children possess considerable health-related knowledge with a healthy diet and physical activity viewed as
the most important factors that keep them healthy (Bendelow, Williams, & Oakley,
1996). It has been reported that children between the ages of 9-11 also were aware of the
relationship between their diet and health, and considered a healthy diet as being one that
did not contain fat. They considered fat to be the cause of heart problems and obesity,
which were considered undesirable for social reasons (Dixey, Sahota, Atwal, & Turner,
2001).
The research on children’s health beliefs from the cognitive developmental
perspective has confirmed the fact that the quality of children’s thoughts about health and
illness changes with cognitive development in interaction with other variables such as
personality, family background, and the child’s personal experience with health (Kalnins
& Love, 1982). The studies provide evidence for cognitive-motivational models (i.e.
models that give a key role to cognition in the self-regulation of motivation to perform a
behavior) such as a Value x Expectancy model in explaining influences on children’s
food intake (Contento et al., 1988; Michela & Contento, 1986).
Factors influencing school-age children’s milk and soft drink intake
School-age children’s milk and soft drink intake
According to Ajzen and Fishbein (1980), behavior can consist of single actions, a
specific behavior performed by someone, or behavioral categories involving sets of
actions. In order to be able to measure a behavior, whether it is a single action or a
37 behavioral category, it has to be defined clearly so that its performance can be determined. The behavior of interest is defined in terms of its target, action, context, and time (Ajzen & Fishbein, 1980). The behaviors in this study are two distinct ones consisting of single actions: milk and soft drink intake. Milk intake in this study is defined as drinking three cups of regular milk every day. Soft drink intake is defined as the amount of regular (not including diet) carbonated beverages ingested per day.
Both behaviors, milk and soft drink intake of school-age children, have been measured at the national (U.S.) level, as well as at the individual study levels, either separately or with other groups of beverages. While some studies have focused on the increase in soft drink consumption, others have equally examined the decline in milk consumption and reduction in calcium intake of American children and adolescents
(Demory-Luce et al., 2004; French et al., 2003; Friedman et al., 2007; Nielsen & Popkin,
2004; Rajeshwari et al., 2005; Rampersaud et al., 2003; Storey, Forshee, & Anderson,
2004). Table 1 presents a description of past research about milk and soft drink intake.
Only data about milk and soft drink intake of subgroups of school-age children have been presented in Table 1.
The majority of the studies examining these behaviors at the national level have investigated trends or patterns of prevalence or change in milk and soft drink consumption between two time points, usually two decades apart (French et al., 2003;
Nielsen & Popkin, 2004; Rajeshwari et al., 2005). These studies have used nationally representative data from the 1977-1978 Nationwide Food Consumption Survey, the
1989-1991 and 1994-1996 Continuing Surveys for Food Intake by individuals (CSFII),
38 the National Health and Nutrition Examination Survey, and the Supplemental Children’s
Survey 1998.
Table 1
Summary of findings about school-age children’s milk and soft drink intake
Source Design Sample Data collection tool Major findings
Berg, Jonsson, Cross- N=1730 pupils in 7-day food record - 42% drank milk at breakfast every day, of whom & Conner sectional Sweden 78% drank ≥1 glass of milk (2000) Age = 11, 13, & - 93% drank milk some time during the week 15 years
Demory-Luce et Longitudinal N = 246 biracial 24-hour dietary - Greater milk consumption in childhood (p ≤ .0001) al. (2004) cohort study young adults recall than in adulthood followed up from - Compared to childhood, greater soft drink age 10 years consumption (P≤.001) in adulthood - No association found between food group consumption patterns and BMI
Fisher, Cross- N=197 girls and - Girls: Three 24- - 88% of girls reported drinking milk, average milk Mitchell, sectional their mothers hour dietary recalls intake was 314 ± 185g Smiciklas- Age = 5 years (2 weekdays, 1 - 91% of girls reported drinking soft drinks Wright, & weekend day) Birch (2000) - Mothers: FFQ
French, Cross- N= 8909 from 3 1-day dietary recall, - Between 1977/1978 and 1994/1998 prevalence of Lin, & sectional national surveys 2-day record soft drink consumption increased 48% and mean Guthrie (2003) Age = 6-17 years intake more than doubled - Increases over time were larger among boys than girls
39
Table 1 (continued ).
Source Design Sample Data collection tool Major findings
Friedman, Randomized N = 356 male and 5 sets of three 24- - 65% to 90% of the children reported consuming Snetselaar, controlled 297 females hour recalls soft drinks which increased more over time Stumbo, Van clinical trial Age = 7.9 to 10.9 - Males consumed more soft drinks than females Horn, Singh, & years at start - Soft drink consumption increased over time and Barton, (2007) (median 7.3 years total milk consumption dropped drastically follow up)
Grimm, Survey N =560 children - Questions about - 30% reported drinking soft drinks daily Harnack, & Age = 8-13 years type of soft drinks - 85% usually drank regular (nondiet) soft drinks Story (2004) consumed (diet Vs - Soft drink consumption was higher among boys regular) and compared with girls (p = .03) frequency of - Intake increased with age (p < .001) consumption
Gummeson, Cross- N = 218 children 4-day breakfast diary No milk consumption data presented Jonsson, & sectional in Sweden Conner (1997) Age =10, 13, & 16 years
Harnack, Stang, Cross- N = 5311 children 2 nonconsecutive 24- - 64.1% of school-age children drank soft drinks & Story (1999) sectional from national hour dietary recalls - Whites were more likely than blacks to consume survey soft drinks Age = 2-18 years - Compared to nonconsumers, soft drink consumers had higher energy intakes and consumed less milk
40
Table 1 (continued).
Source Design Sample Data collection tool Major findings
Kassem, Lee, Cross- N = 707 female Questions about - 96.3% drank soda, 50.1% drank ≥ 2 glasses per day Modeste, & sectional students amount and - Students drank regular soda more than diet soda Johnston (2003) Age = 13-18 years frequency of regular soda consumed
Kassem & Lee Cross- N = 564 male Questions about - 96.5% drank sodas, 60.2% drank ≥ 2 glasses per day (2004) sectional students amount and - Students drank regular soda more than diet soda Age 13-18 years frequency of regular soda consumed
Nielsen, Barry, & Cross- N = 73,345 24-hour food - In 2-18-year-olds, the largest drop in milk Popkin (2004) sectional individuals from 4 recall/record consumption occurred from 13.2% of total energy in national (self/interviewer- 1977 to 8.3% in 2001 and soft drink consumption independent administered) increased from 3% to 6.9 % for the respective years surveys - For same age group between 1977 and 1996, the Age ≥2 years greatest changes occurred in milk and soft drink portions: decrease from 15.4 oz in to 13.6 oz for milk
and increase from 13.6 oz to 21 oz for soft drinks
Rajeshwari, Cross- N = 1548 children 24-hour dietary - Percentage of children consuming sweetened Yang, sectional Age = 10 years recall beverages significantly decreased from 1973 to 1994, Nicklas, & survey especially for soft drinks (p < .01) with no change in Berenson (2005) mean gram amount of soft drinks consumed - Total gram amount of milk consumption was significantly lower in medium to high 41
Table 1 (continued).
Source Design Sample Data collection tool Major findings
sweetened-beverage consumption group (p < .01) - Higher percentage of white (66%) compared to black children (51%) consumed soft drinks - Mean BMI significantly increased (p < .001) from 1973 to 1994 within all sweetened-beverage consumption groups
Rampersaud, Cross- N = 21,662 2 nonconsecutive 24- - Soft drink intake increased dramatically with age Bailey, & sectional individuals from hour dietary recalls beginning around 8 years Kauwell (2003) national survey - Mean soft drink intake exceeded milk intake at age 13 Age = birth to 18 (p < .04) years Storey, Cross- N = 8758 24-hour dietary recall - Soft drink: In 9-18 year olds, 28.9% consumed Forshee, & sectional subjects from none, 30% consumed ≤1 serving, 25.4% Anderson (2004) national survey consumed 1-2 servings, 15.6% consumed >2 Age = groups 2- servings 3, 4-8, 9-13, & - In 9-13 year olds, milk consumption dropped 14-18 years more rapidly in girls compared to boys - Milk consumption in whites and African- Americans declined relatively slower than in Hispanics.
42
43
The data have been gathered mainly by single 24-hour dietary recalls and/or records except in 2 studies where they used two nonconsecutive 24-hour dietary recalls
(Harnack, Stang, & Story, 1999; Rampersaud et al., 2003). However, in some studies the dietary recalls were self-administered and in others, interviewer-administered. Twenty-
four hour dietary recalls are thought to be appropriate for short-term intake rather than long-term ones (Farris & Nicklas, 1993). Similar findings have been obtained across the population-based studies. In general, there is consistent evidence that among American school-age children, between 1970s and 1990s, there has been an alarming increase in the amount of soft drink consumption, thus adding to higher caloric intakes and affecting dietary quality, and a concomitant decline in milk intake, adversely affecting calcium intake (Demory-Luce et al., 2004; French et al., 2003; Harnack et al., 1999; Nielsen &
Popkin, 2004; Rajeshwari et al., 2005; Rampersaud et al., 2003; Storey et al., 2004).
However, contrary to the national trends, Rajeshwari and colleagues (2005) have found that in Bogalusa, LA, the percentage of children drinking soft drinks has decreased from
1973 to 1994. Despite the possible presence of important regional differences in soft drink consumption, there is the need for more studies to confirm these regional differences which may or may not be reflective of national trends.
The design of most of the research relying on national surveys is cross-sectional and relies on broad subgroups by age. This design does not allow follow-up of children’s milk and soda drinking behavior over time to gain an understanding of changing habits from early childhood onwards. In order to better assess changes in eating patterns during age transitions, Demory-Luce and colleagues (2004) collected dietary intake data from a longitudinal sample. They collected dietary intake data from young adults who had
44
participated in a previous cross-sectional survey at 10 years of age. According to Block
(1982) and Thomson et al. (2003), the use of one 24-hour dietary recall is insufficient for characterizing the usual eating patterns of an individual but is adequate for characterizing the eating patterns of large groups of children. Despite having a limitation of using single
24-hour dietary recall with each participant at two time points, the results from this study provided important longitudinal information on changes in food group consumption patterns and were consistent with some of the above cited studies (Demory-Luce et al.,
2004).
Children’s and adolescents’ milk and soft drink intake have also been measured either alone or in conjunction with other foods with smaller samples, mainly to identify factors that influence or predict these behaviors (Berg et al., 2000; Fisher, Mitchell,
Smiciklas-Wright, & Birch, 2000; Grimm et al., 2004; Gummeson, Jonsson, & Conner,
1997; Kassem & Lee, 2004; Kassem, Lee, Modeste, & Johnston, 2003). The data collection tools and intervals are quite different in all these studies. The studies in which influences on soft drink consumption by children and adolescents were examined, the behavior was measured by single questions about frequency of consumption during the past 12 months with preset response items and type of soft drinks usually consumed: diet versus regular and colas with or without phosphoric acid (Kassem & Lee, 2004; Kassem et al., 2003). In the Swedish studies where influences on milk intake by children and adolescents was assessed in addition to other food choices, the behavior was measured either by a precoded 7-day food record (Berg et al., 2000) or a 4-day breakfast diary
(Gummeson et al., 1997) in which participants were asked to mark the days they had consumed the type of foods. In the study where both milk and soft drink intake of both
45 mothers and their daughters was assessed, the behaviors of the daughters were measured by three 24-hour food recalls and that of the mothers by food frequency questionnaires
(FFQ) (Fisher et al., 2000).
From the findings in Table 1, it is difficult to compare prevalence of milk and soft drink intakes across studies. Gummeson et al. (1997) have presented no data about consumption of milk. The figures of milk intake from the other studies (Berg et al., 2000;
Fisher et al., 2000) are somewhat close. The figures about soft drink intake are also varying. Some of the reasons to the discrepancy may be the different methods of measuring the milk and soft drink intake, differences in age groups studied, and varying habits among regions in the U.S. and between countries: Sweden and U.S.
In all these studies, influences and behaviors were measured concurrently except for the Swedish studies (Berg et al., 2000; Gummeson et al., 1997), in which the food choices were measured prospectively by administering the food records two and 6 weeks, respectively, after the TPB questionnaire. In Gummeson et al.’s (1997) study, the rationale for delaying measurement of the behavior was to minimize recall bias from the questionnaire, which could have influenced breakfast choices. However, there was a weak prediction of behavior by the TPB variables. Intention explained only 12% of the variance in choice of milk (Gummeson et al., 1997). Despite efforts to minimize recall bias, the time lapse between responding to the questionnaire and measurement of behavior might be a possible reason for the weak prediction because during this time interval, children’s preferences may have changed. Although not explicitly stated, Berg et al.’s (2000) rationale for having a shorter time lapse between the two measures may have been to minimize the possibility of weak predictions. In their study, intention explained
46
40- 49% of milk choices. Whether the shorter time lapse is the reason for the better
predictions can be determined only by additional studies with prospective designs
investigating influences on children’s milk and soft drink intakes.
In summary, there is a lack of standardized way of measuring milk and soft drink
intake, which makes comparison of both behaviors difficult across studies. Despite this
fact, it is clear from the available research that among school-age children, over the past
thirty years, there has been a tradeoff between milk and soft drink intake with soft drink
consumption increasing with age.
Influencing factors investigated in this study
As stated earlier, despite the importance of understanding determinants of
children’s eating behaviors, few descriptive theoretically-based studies have been
undertaken to identify factors influencing the eating behavior of children. Some of the
atheoretical studies have used various quantitative methods such as questionnaires,
surveys, and interviews to investigate predictors of food-related behavior in general (Le
Bigot Macaux, 2001), for fat and fiber (Berg, Jonsson, Conner, & Lissner, 2002), for
milk and soft drinks (Fisher et al., 2000; Grimm et al., 2004; Lee & Reicks, 2003; May &
Waterhouse, 2003), and dietary milk fat intake by preschool children (Dennison, Erb, &
Jenkins, 2001). Despite the scarcity of the atheoretical and theoretically-based studies
investigating influences on milk and soft drink intake, in the next sections, only the few
studies conducted with school-age children and adolescents will be presented. Table 2
presents a description of past research about influences on school-age children’s and
adolescents’ milk and soft drink intake.
47
Table 2
Summary of relationships between influencing factors and milk and soft drink intake
Source Design Sample Major findings
Berg, Cross- N = 1730 - Correlations between intention Jonsson, & sectional pupils in and milk choices were .63 - .70 Conner Sweden - AT & descriptive norm (strongest (2000) Age =11, 13, predictors), injunctive norm, & & 15 years PBC explained 78-93% of the variance in IN to drink milk - Weight gain valued more negatively among users of lower fat milk - Other influences: father & mother, availability, taste & health - Motivation to comply with: 36% mother’s wishes, 32% father’s wishes - Gender differences: males preferred higher fat milk than girls
De Bruijn, Cross- N = 208 (80 - AT (β = .32, p < .001), SN (β = Kremers, de sectional boys, 128 .22, p = .001), & PBC (β = .16, p = Vries, van girls in .015) significantly associated with Mechelen, & Netherlands IN Brug, (2007) Mean age = - IN was significantly associated 15.2 years with soft drink consumption (β = - .20, p = .003), - The model explained 14% of variance in adolescent soft drink consumption
Fisher, Cross- N = 197 non- - Daughters’ intake of milk and soft Mitchell, sectional Hispanic, drink directly influenced by their Smiciklas- white girls mothers’ intake of these beverages Wright, & and their - Inverse relationship between Birch (2000) mothers mothers’ milk and daughters’ soft Age = 5 years drink intakes - Adjusted model explained 26% of variance in daughters’ milk intake
48
Table 2 (continued). Source Design Sample Major findings
Gummeson, Cross- N = 218 - AT strongest predictor of IN Jonsson, & sectional children in compared to SN and PBC to drink Conner Sweden low fat milk. (1997) Age = 10, - IN explained 2-38% of the variance 13, & 16 in food choice. IN significantly years predicted milk choice - Taste important influence on food choice, friends unimportant for milk choice
Kassem, Lee, Cross- N = 707 - IN & PBC explained 28% of the Modeste, & sectional female variance in soft drink intake Johnston students - AT (strongest predictor), PBC, & (2003) Age = 13-18 SN explained 64% of the variance in years IN to drink soda - Other Influences: taste, quenching thirst, became hyper or had a sugar rush, health, gaining weight, parents, friends, availability, access to vending machines, & enough money to buy soda - Motivation to comply with: doctors’ and parents’ wishes about their soda intake
Kassem & Cross- N = 564 - IN & PBC explained 15% of the Lee (2004) sectional male students variance in soft drink intake Age 13-18 - Attitude (strongest predictor), PBC, & years SN explained 61% of the variance in IN to drink soda - Other Influences: taste, quenching thirst, health, parents (strongest), followed by friends, teacher, doctor, fast food restaurants, availability, advertisement, access to vending machines, & enough money to buy soda - Motivation to comply with: doctors’ and parents’ wishes about soda intake
49
Table 2 (continued).
Source Design Sample Major findings
Lee & Reicks Cross- N = 105 girls, Influences on milk/calcium intake: (2003) sectional 60% Asian taste enjoyment, perception of lactose survey American intolerance, household size, Mean age = availability at home, meal or snack, 13.4 ± .9 years modeling by father (p = .05) & siblings (p < .05), father (p = .001), mother (p = .001), or friends (p = .05) trying to get them drink milk
May & Qualitative N = 32 - Preferred drink: fruit-flavored drinks Waterhouse schoolchildren for 8 to 9-year-olds, soft drinks for 13 (2003) in UK to 14-year-olds Age = 8-9 & - Taste: most important influence on 13-14 years drink choice - Influential factors: parents and friends for younger group, cost, availability, & thirst for older group Note. AT= attitude, SN= subjective norm, PBC= perceived behavioral control, IN= intention
50
Thomas and Znaniecki (1918), who first used the concept of attitude to explain social behavior, explained attitudes as mental processes that determine an individual’s actual and potential responses. Measurement of attitudes has stemmed from the thought that they are causally related to behavior and that they could explain human action because they were considered as behavioral dispositions. This relation holds true both in the common use of the term attitude and in the research literature in social psychology
(Eagly & Chaiken, 1993). However, the empirical evidence for this relationship has not always been supported even in the nutrition literature where studies have been conducted to explore the degree of relationship between attitudes and consumption of certain foods
(Shepherd, 1999). A meta-analysis of such studies revealed evidence for small correlations (r = .18) between attitudes and food choice behavior. In the late 1960s, similar findings in social psychology supported several structured attitude models such as the TRA and the TPB (Armitage & Conner, 2001).
Based on the assumptions that increased knowledge and favorable attitudes toward a specific outcome lead to a desired change in health behavior, the area of attitude change has received the most attention in school health education research (Parcel, 1984).
However, there have been claims that the relationship between attitudes and behavior is too complex to expect that attitudes will be a direct predictor of health behavior (Green,
1979). Consequently, the few studies that have investigated attitudes and milk and soft drink intake among children and adolescents have studied the influence of attitudes on these behaviors through their effect on behavioral intention. In the next section, the relationship between attitudes, subjective norm, and perceived behavioral control with
51
intention will be presented, following which the influence of intention on milk and soda
drinking behavior will be discussed.
The TPB has been used to understand determinants of various behaviors including smoking (Cote, Godin, & Gagne, 2004; Godin, Valois, Lepage, & Desharnais, 1992), alcohol consumption (Schlegel, D'Avernas, Zalma, & DeCourville, 1992), condom use
(Gebhardt, Kuyper, & Greunsven, 2003), breastfeeding (Khoury, Moazzem, Jarjoura,
Carothers, & Hinton, 2005; Swanson & Power, 2005), and physical activity (Craig et al.,
1996; Hagger, Chatzisarantis, Biddle, & Orbell, 2001; Mummery, Spence, & Hudec,
2000; Trost, Saunders, & Ward, 2002). In addition, TRA/TPB have been applied to food choices mostly with adults and adolescents (Backman et al., 2002; Booth-Butterfield &
Reger, 2004; Brewer, Blake, Rankin, & Douglass, 1999; Conner, Norman, & Bell, 2002; de Bruijn, Kremers, de Vries, van Mechelen, & Brug, 2007; Dennison & Shepherd, 1995;
Kassem & Lee, 2004; Kassem et al., 2003; Lien, Lytle, & Komro, 2002). There are only two studies that have used the TPB to predict milk choices of school age-children among other food choices (Berg et al., 2000; Gummeson et al., 1997).
Attitude. Attitudes of participants toward milk and soft drink intake have mostly been investigated in studies using the TPB. In some of the atheoretical studies, attitudes towards food in general and breakfast choices were investigated. Three successive surveys were carried out in 1993, 1995, and 1997 with a sample of 1000 French children aged 9-11 years and their mothers. The purpose was to assess trends in food-related behaviors and their attitudes toward food and nutrition (Le Bigot Macaux, 2001).
Attitudes toward food varied clearly between children and their mothers. In order of importance, children perceived food as vital to stay alive, essential for maintenance of the
52
body, and as a pleasure. In contrast, mothers’ understandings of the meaning of food for
their children were ranked in the opposite direction. Children’s enjoyment of healthy and
unhealthy foods was similar. French fries were the favorite food for the majority of the
children (92%) followed by pasta (89%). Fruits and candy were ranked similarly high (Le
Bigot Macaux, 2001).
Dietary knowledge and beliefs in relation to breakfast choices (mainly fat and
fiber content) of 181 Swedish schoolchildren aged 11 to 15 years were investigated (Berg
et al., 2002). Interviews were conducted using the “stacking box methodology” in which
subjects were asked to select food items among photographs of breakfast foods and to
create hypothetical breakfasts with low fat and high fiber. Knowledge about sources and
health attributes of fiber was related to choices of bread and cereals rich in fiber and,
similarly, a positive attitude toward low fat foods predicted choice of low fat milk products (Berg et al., 2002).
A meta-analysis by Godin and Kok (1996) revealed that the TPB constructs
accounted for 32% of the variance in intentions toward eating behaviors. For eating
behaviors, attitude toward the behavior was a significant predictor, accounting for most
of the explained variance in intention. Congruent with these findings, in studies
investigating determinants of adolescents’ soft drink consumption, attitude was a
significant predictor (p ≤ .0001) of intention to drink soft drinks and, jointly with
subjective norm and perceived behavioral control, explained 64% of the variance in
intention among the females (Kassem et al., 2003) and 61% among the males (Kassem &
Lee, 2004). Among both females and males, attitude was the strongest predictor of intention and had a high statistically significant positive relationship with intention to
53 drink regular soda for females (r = .76, p ≤ .0001) and for males (r = .72, p ≤ .0001).
Similarly, attitude was the strongest predictor of intention to consume soft drink in Dutch adolescents (de Bruijn et al., 2007).
The investigations of different types of milk choices with Swedish 10 to 16-year- old schoolchildren have yielded similar results. In one study, attitude was the most powerful significant predictor (p < .05) of intentions to drink milk with more positive attitudes toward milk being associated with stronger intention to consume it (Gummeson et al., 1997) and in the other study, together with descriptive norms, attitude was also the strongest predictor of intention to drink milk and had moderate to high positive correlations with intention ranging between .43 and .68 (Berg et al., 2000). Comparable to other food choice studies, together with the other TPB variables, attitude explained
66% of the variance in intention to drink milk (Gummeson et al., 1997) and 78-93% of the variance in intention to drink different types of milk (Berg et al., 2000).
Subjective norm. Subjective norm encompasses the influence of the social environment on intentions and behavior. In the TPB, this concept is more restricted than the concept of norms as viewed in sociology. In the TPB, subjective norm refers to particular behavioral direction ascribed to a generalized social agent, whereas in sociology, the term norm refers to a broad range of permissible behaviors (Ajzen &
Fishbein, 1980). Subjective norm refers to one’s perception of what significant others desire concerning the performance or nonperformance of a certain behavior. This perception may or may not be congruent with what significant others think one should do
According to the TPB, one’s intention to perform a behavior will be stronger when one
54 perceives that important others think one should perform a behavior and vice versa
(Ajzen & Fishbein, 1980).
It has been suggested that norms are the weakest construct in predicting behavioral intention (Armitage & Conner, 2001). In a review of the application of the
TPB to health behavior, Godin and Kok (1996) found that values of social norm varied by type of behavior with values being high for social norms about automobile-related and oral hygiene behaviors, yet low for social norms about eating and exercising behaviors.
Similar to Godin and Kok’s (1996) findings, the construct of subjective norm has yielded different results in the milk and soft drink studies, even though both are eating behaviors.
In the two soft drink studies, subjective norm was a significant predictor of intention but had the least contribution (after attitude and perceived behavioral control) in explaining intention, indicating the importance of influences of mainly parents and friends (Kassem
& Lee, 2004; Kassem et al., 2003). In Gummeson et al.’s (1997) and de Bruijn et al.’s
(2007) studies, subjective norm was a significant predictor of intention with stronger social pressure to drink milk associated with greater intention to do so and with those who perceived less subjective norm towards limited soft drink intake drinking less soft drink. However, subjective norm ranked second after attitude in strength of prediction.
Contrary to the above findings, together with attitude, descriptive norm (perception of significant others’ preferences) was the strongest predictor of intention in the choice of milk in Berg et al.’s study (2000).
According to Armitage and Conner (2001), the weak predictive power of the normative component may be partially explained by weaknesses in measurement. For example, overall, norms have been measured by a single item. In addition, subjective
55
norm is usually operationalized as an injunctive norm i.e. social approval by significant
others. However, responses to injunctive norm questions have resulted in low variability
due to high social desirability i.e. significant others are generally thought of as approving
of desirable behaviors and disapproving of undesirable ones (Ajzen, 2002). As a possible
solution, Ajzen (2002) recommends the inclusion of items tapping descriptive norms i.e. whether important others themselves perform the particular behavior or not. This is based on Social Learning Theory’s premise that observational learning through modeling is a significant determinant of behavior (Bandura, 1986). There is growing empirical support
for the addition of descriptive norm to the TPB and its predictive validity of behavioral
intention with older age groups; however, its use with children is not common. Berg et al.
(2000) incorporated the concepts of descriptive and injunctive norms, as subsets of
subjective norm, in their study. The use of descriptive norm in the statistical model
improved the predictive power of the other constructs on intents to consume the different
alternatives of milk. However, in the other study about milk choice and the soft drink
studies, this concept was operationalized as injunctive norm (Gummeson et al., 1997;
Kassem & Lee, 2004; Kassem et al., 2003). A possible reason for the varied results may
be the different ways the concept of subjective norm was operationalized in these studies.
Perceived behavioral control. Perceived behavioral control is assumed to tap
external factors such as availability of resources like time, money, social support, and
internal factors such as ability, skills, and information. Ajzen (1998) argued that
perceived behavioral control is synonymous with self-efficacy and he added perceived
behavioral control to TPB to address human behavior that is not under complete
volitional control. Self-efficacy refers to individuals’ beliefs in their capabilities to
56 achieve various levels of performance attainment (Bandura, 1977). According to Bandura
(1982), people’s beliefs in their efficiency influence the choices they make, the extent of effort they exert in their actions, the extent of perseverance when facing difficulties, and their vulnerability to stress and depression.
According to Ajzen (Ajzen, 2002), a direct measure of perceived behavioral control that reflects an individual’s confidence in performing a behavior should include both self-efficacy and controllability items. The self-efficacy items tap the idea of one’s ease or difficulty in performing a certain behavior and the controllability items tap the control one has over performing the behavior. However, Bandura (1986) has argued that self-efficacy and control are different concepts. Results for other health behaviors have been contradictory. A comparison of the TRA, TPB, and the Social Cognitive Theory in physical activity participation was conducted, and self-efficacy, rather than perceived behavioral control, was found to directly influence behavior (Dzewaltowski, Noble, &
Shaw, 1990). Others have found perceived behavioral control to influence behavior and self-efficacy to influence intention (Terry & O'Leary, 1995; White, Terry, & Hogg,
1994). These contradictory findings do not solve the issue whether self-efficacy and perceived behavioral control are the same or different constructs.
Inclusion of a measure of perceived behavioral control in studies of food choice may be an important predictor of some food choices. Within the studies of milk and soft drink intake, perceived behavioral control was a significant predictor of intention; however it ranked second (Berg et al., 2000; Gummeson et al., 1997; Kassem & Lee,
2004; Kassem et al., 2003) and third (de Bruijn et al., 2007) after attitude in strength of the prediction. When comparing the influence of perceived behavioral control on
57
behavior across the studies, similarly mixed findings were found. Contrary to Ajzen’s
(1991) suggestion, perceived behavioral control was not a significant independent
predictor of milk drinking and soda drinking behavior (Gummeson et al., 1997; Kassem
& Lee, 2004; Kassem et al., 2003). However, in Berg et al.’s (2000) study, intention
predicted choice of milk and perceived behavioral control added significantly to the
prediction. This finding is consistent with another study of Norwegian 10-12 year olds in
which, among other Social Cognitive Theory factors investigated, self-efficacy was a
strong correlate to fruit and vegetable consumption (Bere & Klepp, 2004). The lack of an
independent contribution of perceived behavioral control to behavior in these studies may
have been due to either inaccurate measurement of the concept or participants’ inaccurate
perception of their degree of control over their behavior.
Intention. Expressions of behavioral intention are expected to accurately predict a
corresponding volitional action, thus acting as close antecedents of overt behavior
(Ajzen, 1988). If this holds true, then intentions should correlate more strongly with
behavior than other antecedents. In a meta-analysis, the TPB was found to account for
34% of the variance in a variety of health behaviors across different age-groups (Godin &
Kok, 1996), which is considered to be a relatively good explanation for psychosocial variables (Baranowski et al., 1999). Intention was the most important predictor of behavior; however, in almost half the studies, perceived behavioral control significantly added to the prediction (Godin & Kok, 1996). In another review of studies conducted to investigate psychosocial correlates of dietary behavior, the predictiveness of the different models, including the TPB, has been found to be low (R2 < 0.3) with adults and
adolescents and even lower for children (Baranowski et al., 1999). The R2 values were
58
higher when the models were used to predict specific categories of foods, suggesting that influences vary by food types.
In the studies with children and adolescents, intention was a significant predictor of milk and soda drinking behavior (Berg et al., 2000; de Bruijn et al., 2007; Gummeson et al., 1997; Kassem & Lee, 2004; Kassem et al., 2003); however, despite all having specific categories of foods to be predicted, the predictive values were not better than the
34% variance accounted for health behaviors found in the meta-analysis (Godin & Kok,
1996). With the females, intention and perceived behavioral control explained more of the variance in soft drink intake (28%) than with males (15%) (Kassem & Lee, 2004;
Kassem et al., 2003). In Gummeson et al.’s (1997) study, prediction of actual food choices were relatively poor (2 to 38% variability) and behavior was only weakly to moderately related to intention; however, similar to the other studies of soft drink, intention was a significant predictor of milk choice, predicting 12% of this behavior. A possible reason for the relatively small predictions in Gummeson et al.’s (1997) study could be that intention changed in the 6 weeks interval between administration of the
TPB measures and then the behavior measures. Overall, the relatively low predictive power of intention for milk and soda drinking behavior may be because in these studies, the behavior being predicted was current use of soft drink or milk, whereas the intention measured was intention to drink milk/soft drink in the future.
Taste. Taste appears to be an important factor influencing children’s food choices
(Birch & Fisher, 1998; Michela & Contento, 1986), including their decision to drink milk and soft drink (Kassem & Lee, 2004; Kassem et al., 2003; Neumark-Sztainer, Story,
Perry, & Casey, 1999). Milk flavor influences children’s milk drinking behavior
59
(Nicklas, 2003). Children who drank flavored milk had lower intake of soft drinks and
higher calcium intake compared to those who did not drink flavored milk (Johnson,
Frary, & Wang, 2002). Findings have been the same with soft drink. In a sample of 560
children 8 to 13 years old, who completed mail-in surveys investigating factors associated with their consumption of soft drinks, the children reporting the strongest taste preference were 4.5 times more likely to consume soft drinks five or more times per week than subjects with less taste preference (Grimm et al., 2004). Consistent with these
findings, among both children and adolescents, taste enjoyment has been an important
factor influencing choice of soft drink (Grimm et al., 2004; May & Waterhouse, 2003),
attitude toward soft drink intake (Kassem & Lee, 2004; Kassem et al., 2003), choice of
milk (Lee & Reicks, 2003), and attitude toward milk intake (Berg et al., 2000;
Gummeson et al., 1997).
Concern about body weight. There is a misconception about that milk is fattening,
which may lead children, especially females, to limit their milk intake to lose or maintain
weight (Neumark-Sztainer et al., 1999; Wells, 1994). In a survey by Seaman and
colleagues (1997), children’s concerns about healthy diet were related to body size rather
than diet-related chronic diseases. Weight gain was an influential factor for attitude toward soft drink intake among only females (Kassem et al., 2003) and for attitude
toward milk intake in one of the Swedish studies (Berg et al., 2000). Together with
dieting, concerns about weight gain may be an important predictor of food choice.
Parents and friends. Parents have been found to play a crucial role in influencing their children’s food habits and preferences by making certain foods available, acting as
60
models, and by their own eating behavior (Birch & Fisher, 1998; Koivisto Hursti, 1999).
Parental soft drink intake has been positively related to children’s soft drink intake
(Grimm et al., 2004; Vereecken, Keukelier, & Maes, 2004). Children whose parents
regularly drank soft drinks were 2.8 times more likely to consume soft drinks five or
more times per week than children whose parents did not regularly drink soft drinks
(Grimm et al., 2004). In another study in which structural equation modeling was used to
predict 5- year-old girls’ milk and soft drink intake, similar results were obtained (Fisher
et al., 2000). Subjects whose mothers drank milk more frequently were found to consume
milk more frequently and drank less soft drinks. For both mothers and daughters, soft
drink consumption was negatively associated with milk and calcium intake (Fisher et al.,
2000). In a more recent study examining the association between family cohesion and
behaviors linked to health or overweight in adolescents girls, family cohesion was
significantly associated with less soda intake and was a predictor of a trend in milk
consumption (Franko, Thompson, Bauserman, Affenito, & Striegel-Moore, 2008).
Consistent with these findings, parents and friends have been important influences
on children’s and adolescents’ soft drink intake, milk intake, and subjective norm to soft
drink and milk intake (Berg et al., 2000; Grimm et al., 2004; Kassem & Lee, 2004;
Kassem et al., 2003; Lee & Reicks, 2003). In all these studies, parents were more
important influences than friends. With milk choice, mothers appeared to be slightly
more important than fathers with 36% of children wishing to comply with mother’s
choices about breakfast food and 32% with that of father’s (Berg et al., 2000). With soft
drink intake, participants were motivated to comply with doctors’ and parents’ wishes
about their soda intake (Kassem & Lee, 2004; Kassem et al., 2003).
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Health. Feeling healthy by drinking milk and regular soda was a predictor of attitude toward milk and soft drink intake only in two studies using the TPB (Berg et al.,
2000; Kassem & Lee, 2004; Kassem et al., 2003)
Availability. Availability of food items has been found to be quite consistently an important predictor of consumption. Availability of milk at home and soft drink at home and school were consistently associated with intake of milk and soft drink (Berg et al.,
2000; Grimm et al., 2004; Kassem & Lee, 2004; Kassem et al., 2003; Lee & Reicks,
2003). This is particularly important in studies of school-age children who are less likely to be influential in the availability of milk and soft drinks.
Gender. Few studies have investigated how variations in gender influence food choice decisions among children and adolescents. Gender differences have been found in soft drink consumption with males consuming soda significantly more than females (p =
.03) (Grimm et al., 2004). Also, female gender has shown to have a negative association to milk and calcium intake among 10-18-year-olds (Novotny et al., 2003). Overall, Berg et al. (2000) found similar gender variations in milk intake to that of other studies among adolescents with other foods (Backman et al., 2002; Cusatis & Shannon, 1996; Dennison
& Shepherd, 1995; Lien et al., 2002). Only frequency of skim milk intake was higher among females than males. Gender differences were found in intentions and attitudes with males being more in favor of whole milk than females. No significant gender differences were found for the TPB constructs on intention and consumption. Compared to boys, girls evaluated high fat intake and weight gain more negatively. These differences are consistent with the literature about gender differences related to restriction
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of food intake by female adolescents because of dissatisfaction with body shape and size
(Dennison & Shepherd, 1995).
Ethnicity. Compared to other food choices of adolescents, the effect of ethnicity
has been less investigated with children’s and adolescents’ actual milk and soda drinking
behavior and no studies have investigated the effect of ethnicity on the influences on
children’s milk and soft drink intake. The available data is about its effect on actual
consumption of milk. There have been consistent findings with milk intake of children
and adolescents. Asian ethnicity has been found to have a negative association with milk
and calcium intake and compared to Caucasians, Asians consumed less milk and calcium
(Novotny et al., 2003; Oshiro, Novotny, & Titchenal, 2003). African American males
ages 9 to 18 years and females 4 to 18 years have been also found to consume
significantly less milk than their non-African American counterparts (1.03 vs 1.61 and
.94 vs 1.32 servings per day respectively, p < .05) (Fulgoni et al., 2007). An important issue for ethnicity and milk consumption is the higher rates of lactose intolerance among
African Americans and Asian Americans (Nicklas, 2003). There have been consistent findings about ethnic differences in actual soft drinks intake of children. Whites have been more likely than blacks to consume soft drinks (Harnack et al., 1999; Rajeshwari et al., 2005).
BMI. The association of BMI and food choice has been investigated relatively little in children. In one study, no association was found between food group consumption patterns and BMI of young adults (Demory-Luce et al., 2004). For 10-year- olds, mean BMI significantly increased (P <.001) from 1973 to 1994 among sweetened-
beverage consumers (Rajeshwari et al., 2005). In a study evaluating diet quality and BMI
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by beverage patterns, for children aged 6 to 11 years, BMI was found to be significantly
higher (p < 0.05) in the soda patterns (adjusted mean BMI = 18.7) compared to the high-
fat milk patterns (adjusted mean BMI = 17.8) (LaRowe et al., 2007). In another study examining associations between parent and child attitudes and behavior related to eating and weight, children’s BMI was positively related to attitudes to eating and their weight
(r = .22, p < .05) and their attitudes and behavior for themselves and their perceptions of their parents (r = .24, .23, respectively, p < .05) (Baker, Whisman, & Brownell, 2000).
Similarly, Kuchler and Lin (2002) established a positive correlation between BMI and attitudes towards diet in adults.
Other influences
There are multiple other community and environmental level influences on school-age children’s milk and soft drink intake some of which are breakfast consumption and school meals, meal patterns, fast food consumption, lactose intolerance, and marketing of soft drinks.
Breakfast consumption and school meals. Eating breakfast is important for the overall dietary quality and adequacy in school-age children and has a positive influence on milk intake (Chitra & Reddy, 2007). However, breakfast consumption among children has declined significantly between 1965 and 1991(Siega-Riz, Popkin, & Carson, 1998).
Participation in the School Breakfast Program (SBP) and the National School Lunch
Program (NSLP) has improved children’s daily nutrient intake, including milk and milk
products which, in turn, has been associated with significant improvements in student
academic performance and psychosocial functioning (Kleinman et al., 2002; Pearson,
Biddle, & Gorely, 2008). Children participating in the NSLP and the SBP and are less
64
likely than nonparticipants to consume soft drinks and are more likely to consume milk, consequently having higher intake of calcium and essential micronutrients (Gordon &
McKinney, 1995). Furthermore, breakfast skipping among children has been associated
with an increased likelihood of being overweight (Dubois, Girard, Potvin Kent, Farmer,
& Tatone-Tokuda, 2008); whereas, breakfast consumption has been associated with a
lower BMI (Delva, Johnston, & O'Malley, 2007).
Meal patterns. The traditional pattern of families eating meals together at the
kitchen table has changed. Currently, fewer families eat meals together (Nicklas &
Johnson, 2004) and with time, the frequency of family dinners have decreased (Gillman
et al., 2000). In a survey with children 9-15 years old in 1995, five percent less children reported eating with their families (Gillman et al., 2000). Increased frequency of family
dinners at home has been positively associated with healthful dietary intake patterns such
as substantially higher intake of several nutrients, including calcium and lower intake of
soft drinks, hence a lower glycemic load (Gillman et al., 2000; Neumark-Sztainer,
Hannan, Story, Croll, & Perry, 2003).
Fast-food consumption. The frequency of fast-food consumption has increased
considerably since the early 1970s and fast-food consumption has become especially
popular among children and adolescents (Lin, Guthrie, & Frazao, 1999). Fast-food
consumption, among other foods, has been associated with higher intake of soft drinks
and lower intake of milk (French, Story, Neumark-Sztainer, Fulkerson, & Hannan, 2001;
Paeratakul, Ferdinand, Champagne, Ryan, & Bray, 2003).
Lactose intolerance. In the U.S., Caucasians have the lowest prevalence of lactose
intolerance (15%), whereas African-Americans and Asian-Americans have the highest
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prevalence (80% and 90% respectively) (Nicklas, 2003). Individuals with lactose
intolerance have a common misconception that they cannot consume dairy products
because they will have gastrointestinal symptoms, thus eliminating or minimizing intake
of milk and dairy foods ( Lee & Reicks, 2003). Despite these figures, their validity has
been challenged and the prevalence of lactose intolerance has been found to be
profoundly overestimated (Jarvis & Miller, 2002).
Marketing of soft drinks. The dramatic increase in soft drink consumption mainly
among children and adolescents has been associated with extensive unprecedented
marketing of soft drinks, using pop culture and sports icons to target specifically children
(Austin & Rich, 2001; Nestle, 2000). Television viewing and advertisements have been
found to influence children’s and adolescents’ higher soft drink intake (Grimm et al.,
2004; Kassem & Lee, 2004). Another means of advertising that promotes soft drink
intake among children is the recent phenomenon of “pouring rights” contracts, in which,
to assist with budget constraints, adverting and sales arrangements from soft drink
manufacturers are present at schools (Nestle, 2000).
Cost. Cost and enough money to buy soft drink were influences on mostly
adolescents’ soft drink consumption (Kassem & Lee, 2004; Kassem et al., 2003; May &
Waterhouse, 2003). This may be because, compared to children, adolescents are more independent in making food choices and purchasing items.
In summary, among influences on children’s and adolescents’ milk and soft drink
intake, attitudes, subjective, norm, and perceived behavioral control explained a
considerable amount of the variance in intention to drink milk and soft drinks, comparing
favorably to other food choice studies. However, the reason for the relatively low
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predictive power of intention on actual behavior still remains unclear. Among the other
influences, relatively more consistent findings were obtained with taste, weight concerns,
health, availability, parents and friends. Due to the limited number of studies
investigating influences on children’s milk intake and no such study with children’s soft
drink intake, these influences will be investigated among American children in this study.
Summary for literature review
Childhood obesity has been on the rise over the past three decades and is reaching
epidemic proportions in the U.S. Some of the possible causes are thought to be the rise in
soft drink consumption, which is a significant contributor for total caloric intake for
especially children, and the accompanying decline in milk intake by American school-age
children. Despite the national initiatives and the ones by the health promotion
organizations to promote healthy eating behavior among children, American children do
not meet the dietary guidelines and recommendations mainly for added sugars and
calcium. An understanding of factors influencing milk and soft drink intake of school-age
children is essential to intervene properly and minimize associated health issues.
Numerous reasons at the community level for the increase in soft drink intake and
the accompanying drop in milk consumption among school-age children have been
suggested. Relatively little is known about the factors that influence school-age children’s milk and soft drink consumption. The few studies presented in the review of the literature have investigated soft drink consumption and intake of various types of milk among other foods in older age groups. In addition to a small number of research studies that have investigated influences on school-age children’s milk and soft drink behavior, there have been few theoretically-based research studies in which the researchers have developed
67 instruments for the purposes of the studies. This makes it difficult to compare findings across studies and draw conclusions.
Evidence suggests that more research is needed about psychosocial factors at the personal level that influence school-age children’s milk and soft drink intake in order to better understand reasons for the increased soft drink intake and decrease in milk intake.
Therefore this study adds to our understanding of influences on milk and regular soft drink intake among younger children in the U.S., which would assist in planning effective intervention strategies to improve the health and quality of life of American children.
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CHAPTER THREE
Methods
This chapter describes the methods for this study. The following are the components to be discussed: design, sample, sample size determination, sampling procedure, setting, measurement, procedure, data management, data analysis, and protection of human subjects.
Design
Because there is a scarcity of available literature and the need for quantitative studies to understand factors influencing school age children’s eating behavior in the
U.S., a cross-sectional descriptive correlational design was used to determine whether the
TPB constructs predict behavioral intention about milk and soft drink intake which, in turn, predict milk and soft drink intake. The effects of gender, ethnicity, and BMI on the
TPB constructs also were studied. The ultimate aim of the description of the factors influencing children’s eating behavior is to generate knowledge which may serve as a basis for further research.
Setting
Children spend a considerable amount of their time per day in school and hence most research with school aged children is conducted in school settings (Bendelow et al.,
1996; Berg et al., 2000; Dixey et al., 2001; Edwards & Hartwell, 2002; Gummeson et al.,
1997; Hymovich, 1997; Seaman et al., 1997). Despite this fact, it was not possible to gain access to children in schools in Northeast Ohio. Instead, Kaiser Permanente Ohio (KPO) agreed to collaborate and based on their requirement, the researcher went through an
69
unpaid internship at KPO to familiarize herself with their computer system for the
sampling procedure.
Kaiser Permanente (KP) is an integrated managed care organization, and is a
consortium of the Kaiser Foundation Health Plan, Inc. and the Ohio Permanente Medical
Group. Participants were recruited from those receiving care from the 11 KP facilities in
6 counties that comprise the entire Northeast Ohio KP region. The population census
varies monthly; however, Kaiser Permanente Ohio (KPO) serves approximately 73,000 children each year. In the KPO region, there are 150,315 health plan members. While racial and ethnic data is not available for KP’s members, Greater Cleveland’s population is approximately 51% African American and in areas where KP’s medical center offices are located, such as Bedford, about 67% of the population is African American.
Sample
There is evidence that children’s food choices are established from the sixth to twelfth grade, so health promotion interventions should begin prior to sixth grade before these eating patterns become resistant to change (Kelder, Perry, Klepp, & Lytle, 1994).
Based on this evidence, a random sample of school-age children receiving care from a northeastern Ohio Health Maintenance Organization (HMO) was chosen to participate in
this study to generate data about milk and soft drink intake. The inclusion criteria were:
(a) 10-11 years old and (b) in generally good health. This age group was chosen to ensure
that the participants were at the concrete operations level of Piaget’s cognitive
developmental stages, a prerequisite to be able to fill out the questionnaires for this study.
Children with the following health conditions were excluded because the focus was on
healthy children: small for gestational age (SGA), low birth weight babies with poor
70 catch-up growth, chronic feeding difficulties from neurological and muscular disorders, food and milk intolerance or allergies, diabetes mellitus, diabetes insipidus, thyroid disease, parathyroid disease, polycystic ovary syndrome (PCOS), chronic inflammatory diseases i.e. Crohns Disease, colitis, short gut syndrome, gastroesophageal reflux disease
(GERD), gastrostomy feedings, chronic renal diseases, bulimia, anorexia nervosa, Prader-
Willi Syndrome, autism, childhood malignancies and chronic hematological disorders,
Trisomy 21, Trisomy 13-15, 18, Cri-du-chat, fetal alcohol syndrome, Williams
Syndrome, and global developmental delays.
Sample size determination
Sample size was calculated using the power analysis procedure based on Cohen
(1988). Four parameters are needed in power analysis: alpha, beta, power, and effect size.
Power is the probability that a statistical test will lead to the rejection of the null hypothesis
(Cohen, 1988). Based on the fact that understanding predictors of healthy eating behavior in children is a relatively new area of research, both type I and type II errors are important.
Alpha was set at .05 and power at .90.
Effect size (ES) is the degree to which the null hypothesis is false (Cohen, 1988) i.e. how much relationship there is between the dependent and the independent variables. Due to the presence of few studies investigating predictors of children’s eating behavior, determination of the parameters for sample size calculation in this study were based on
Gummeson et al.’s (1997) because their sample included 10 to 11-year-olds whose milk drinking behavior was investigated, in addition to other food choices, using the TPB. In this study, R2s between .02 and .38 have been obtained when explaining food choices
(behavior) by intention and perceived behavioral control, and R2s between .50 and .84 were
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obtained when explaining intention by attitudes, subjective norm, and perceived behavioral
control (Gummeson et al., 1997). Using the mean of the R2 ranges obtained, an R2 = .44 is
translated into an ES f 2 = R2/ 1- R2 = .79 which is considered a large ES (Cohen, 1988).
However, since the ranges of the explained variances are so wide and this study is not
identical to the one cited above, to be conservative, a medium ES of .15 was used.
Based on Cohen (1988), sample size for multiple regression was determined as
2 2 follows: N= (L/f ) + K +1 where N is sample size, L is lambda, f is the effect size, and K
is the number of independent variables. With an ES of .15, a power of .90, a significance
level alpha = .05, Lambda = 19.4 (based on table value at a power of .90, significance alpha
level of .05, 7 independent variables) and 7 independent variables, the estimated total
sample size required for this study was (19.4/.15) + 7 + 1= 137. Based on GPower, with the
same parameters and 7 predictors, the required sample size is 130. The estimated total
sample size of 137 participants was chosen for this study. As noted below, we over- sampled to obtain sufficient sample size.
Using two groups for gender (male/female) and ethnicity (white/ethnic or racial minority), and Student’s t tests using the same parameters (alpha = .05, medium effect size for t test = .50), with 137 subjects, the power is .90. Based on our understanding of the population served by Kaiser Permanente Ohio (KPO), we did not anticipate having difficulty obtaining sufficient numbers of subjects by gender or ethnicity. Using three categories of BMI-for-age percentile (healthy weight, at risk of overweight, overweight),
analysis of variance with a medium effect size (medium effect size for ANOVA = .25)
and alpha = .05 with 137 subjects results in a power of .79.
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Sampling procedure
The researcher identified the ICD-9 codes for the exclusion criteria. Using
the inclusion criteria and the ICD- 9 codes, an information analyst at KPO identified the
subject pool of children participating with KPO and obtained a list of 3355 male and
female participants. Simple random sampling technique was used to obtain participants
from the subject pool. The researcher did a draw of numbers one to five to indicate the starting point of random selection. From the list of 3355 members, starting number 1, every 5th child was chosen until a sample of 600 participants was obtained. A simple random sample was used to ensure representativeness of all 10 to 11-year-olds in
Cleveland, Ohio with diverse ethnic and socioeconomic backgrounds. We purposely over-sampled because of the expected response rate of 23% to a mailed survey (Dillman,
1978).
Measurement
In this study, four assessment measures were used: (1) demographic characteristics form: Tell me about yourself (Appendix A), (2) 24-hour dietary recall for milk and soft drink intake (Appendix B), (3) Milk Intake Questionnaire (Appendix C), and (4) Soda Pop Intake Questionnaire (Appendix D). All the above mentioned measures were designed for the purpose of this study. The direct measures of the TPB constructs in the Milk Intake Questionnaire and the Soda Pop Intake Questionnaire were constructed based on Ajzen’s (2002) recommendation to construct measures in the formative stages of an investigation and his guidelines. Due to time and cost constraints, it was not feasible to conduct a study to elicit children’s beliefs about milk and soft drink. Thus the beliefs for this study were determined from the most recurrent ones in previous
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investigations about various food choices, including milk and soft drink with same or
similar age groups (Backman et al., 2002; Berg et al., 2000; Gummeson et al., 1997;
Kassem & Lee, 2004; Kassem et al., 2003) and the belief-based measures were developed based on Ajzen’s (2002) recommendations.
In a pilot study conducted with fifth grade students to develop and validate questionnaires measuring psychosocial determinants of physical activity, it was reported that fifth graders had difficulty with understanding 5-point scales, and thus they were reduced to 2-point scales (Saunders et al., 1997). Others have also used 3-point Likert scale with responses consisting of +1 (yes), -1 (no), and 0 (not sure) (Trost et al., 2002).
Although such modifications have been reported to be necessary when attempting to collect meaningful self-report data from preadolescents (Ware, 1989), reductions from a 5-point to a dichotomous (Yes or No) scale may minimize variance. To avoid this problem from occurring and to generate interval-level data that allow greater variance of responses, instead of using Likert-type scales, visual analogue scales (VAS) were constructed for the
Milk Intake and Soda Pop Intake Questionnaires.
Questionnaires
The study variables in the theoretical model were measured by separate but similar statements for milk and soft drink intake with bipolar adjectives as responses. In the initial stage of questionnaire development, content validity was evaluated by having two faculty members with expertise in the TPB and a registered dietitian review the questionnaires for relevance, representativeness, and specificity. Consequently, the questionnaires were modified based on their input. Internal consistency was determined by examining Cronbach’s alpha for questionnaire items.
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Pilot study. The questionnaires of this study and the 24-hour dietary recall were pretested with 10 fifth graders during a pilot study to ensure their applicability and usefulness with this age group. The purposes of the pretesting of the questionnaires included the following as suggested by Converse and Presser (1986). First, the level of variation in responses was tested. Converse and Presser (1986) suggest that skewed distributions from a pretest can serve as a preliminary warning sign for lack of response variation. Second, detection of skip patterns was examined. Third, approximate timing required to accomplish the questionnaires was determined. Finally, task difficulty and respondent interest and attention were assessed by asking the participants’ feedback. The results of each research question in the pilot study were as follows:
1- What is the level of variation in responses?
In general, the items of The Milk Intake Questionnaire and The Soda Pop Intake
Questionnaire had an acceptable level of variation in the pilot study participants. Refer to
Table 3 and Table 4 for individual ranges of scores in both questionnaires.
2- Are there any skip patterns in responses?
No skip patterns were found. The only item that a participant skipped intentionally was the last question in the 24-hour dietary recall which asks the respondent to choose between milk and soda pop. The participant suggested to add a ‘none’ response category due to lack of choice from the available options.
3- What is the approximate timing required to accomplish the questionnaires?
The average time needed to complete the measures and the demographic
characteristics form was 15 minutes.
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Table 3.
Ranges of the items in the Milk Intake Questionnaire from the pilot study
Item Range
I plan to drink 3 cups of milk every day for the next month -2 -1 How likely is it that you will drink 3 cups of milk every day for the next -2 -1 month For me drinking milk is important/not important 8 -100 For me drinking milk is good/bad 1 -100 For me drinking milk is enjoyable/unenjoyable 8 -100 How much do you like milk? 1 -100 Drinking milk makes me healthy 0 - 45 Milk tastes good/bad 0 -100 Drinking milk helps me gain weight 0 -100 For me being healthy is important/not important 0 - 41 For me taste of milk is important/not important 0 - 87 For me gaining weight is good/bad 36 -100 Important people think I should drink 3 cups of milk every day 0 - 69 Most people who are important to me drink 3 cups of milk every day 39 -100 My family thinks I should drink 3 cups of milk every day 0 - 84 My family drinks 3 cups of milk every day 8 -100 When it comes to drinking milk, I want to do as my family thinks 0 -100 Drinking 3 cups of milk every day would be easy/difficult 0 -100 I can decide if I drink 3 cups of milk every day 0 - 64 Do you always get to choose what you drink at home? 0 - 100 Is there milk in your refrigerator? 0 - 16 Having milk in the refrigerator makes it easier to drink 3 cups every day 0 - 80 My parents offer me milk with meals 0 - 82 Do you drink milk at school? 0 -100 Having milk available at school makes it easier to drink 3 cups every day 0 -100 Do you drink milk at school because it is given to you? 0 -100
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Table 4.
Ranges of the items in the Soda Pop Intake Questionnaire from the pilot study
Item Range
I plan to drink soda pop every day -2 -2 How likely is it that you will drink soda pop every day? -2 -1 For me drinking soda pop every day for the next month is important/not 40 -100 important For me drinking soda pop is good/bad 0 – 69 For me drinking soda pop is enjoyable/unenjoyable 0 -100 How much do you like soda pop? 0 -100 Drinking sod pop makes me healthy 74 -100 Soda pop tastes good/bad 0 -100 Drinking soda pop helps me gain weight 0 – 57 For me taste of soda pop is important/not important 0 -100 Important people think I should drink soda pop every day 22 -100 Most people who are important to me drink soda pop every day 0 -100 My family thinks I should drink soda pop every day 0 -100 My family drinks soda pop every day 0 -100 When it comes to drinking soda pop, I want to do as my family thinks 0 -100 Drinking soda pop every day would be easy/difficult 0 -100 I can decide if I drink soda pop every day 0 – 78 How much control do you have over drinking soda pop every day? 0 -100 Do you always get to choose what to drink? 0 – 78 Is there soda pop in your refrigerator? 0 – 84 Having soda pop in the refrigerator makes it easier to drink every day 0 -100 My parents offer me soda pop with meals 0 -100 Do you drink soda pop at school? 100-100 Having soda pop available at school makes it easier to drink every day 0 -100
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In addition to the above questions, responses to the following open ended question
were obtained from the participants:
4- Which questions were the most difficult for you to understand and to answer?
None of the participants indicated having difficulty with any question. The only one
they could not understand was the term “Caucasian” in the race/ethnicity item from the demographic characteristics form, which was changed to “White”. The participants further offered the following suggestions:
- Add response category ‘None’ for the choice of drink in the 24-hour dietary recall.
- “Indicate the midpoint on the VAS by a mark so we won’t be off the midpoint if we
need to indicate it.”
- “Responding to the VAS would be easier with set numbers on it Ex. On a scale of
one to 10 which one would you choose?”
However, recommendations on the use of VAS suggest keeping them free of
numerical labels in order to minimize bias seen in Likert-type scales where respondents
may easily associate higher scores with a more positive response and lower scores with
more negative ones (Lee & Kieckhefer, 1989). Consequently, it was opted to keep the VAS
questions for this study without numerical labels. To minimize possible response bias, the
positive and negative end anchors of the VAS items were initially counterbalanced. In the
pilot study results it was noted that the counterbalanced anchors raised confusion among
the respondents. Consequently, all the end anchors were changed with negative on the left
of the VAS and positive on the right.
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Outcome variables
Behavior. In this study, milk intake is defined as drinking 3 cups of milk every
day and soft drink intake is defined as drinking regular carbonated beverages every day.
Both behaviors were measured by a 24-hour dietary recall (Appendix B). Despite having
some disadvantages, diet record keeping by children has become a popular approach to
involving them in modifying their own eating behaviors (Farris & Nicklas, 1993). The
quality of diet diaries may deteriorate over an extended recording period such as 7 days
(Farris & Nicklas, 1993). Therefore, instead of using extensive diaries for this study,
participants were asked to indicate by placing a sign (X) on preset responses if they had
lunch, supper, and breakfast during the 24 hours prior to data collection, whether or not
they had milk or soft drink that day, and how much milk and soda pop they drink on a
usual day during the school week. They were also asked to indicate their choice between
milk and soda pop. In the following section, the measures of each concept will be
presented with examples. Refer to Appendix C and D for the complete version of the
measures.
Influencing factors
To minimize subject burden especially with school-age children, we chose to use the least number of items for each construct in the questionnaires but still be able to measure the variables. For example, for referents, we chose to examine influences of only friends and family. The same is true with attitude (behavioral belief) and perceived behavioral control (control beliefs).
Behavioral intention. In this study, intention refers to a person’s perceived likelihood of drinking 3 cups of milk and drinking soda daily. The participants rated the
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following two items from the Intention to Drink Milk and Soda Pop Scales: ‘I plan to
drink 3 cups of milk/drink soda pop every day,’ and ‘How likely is it that you will drink 3
cups of milk/drink soda pop every day.’ These items have 5 response categories ranging
from ‘Definitely not’ (-2) to ‘Definitely yes’ (2). ‘Don’t Know’ (0) was included to avoid
guessing of responses. Scores from the two items in each scale were added with total
possible scores ranging from -4 to 4. A total score of 0 indicates neutral intention to drink
milk or soda pop, negative scores indicate negative intention, and positive scores stronger
intention. The Cronbach’s alpha for the Intention to Drink Milk and Soda Pop Scales
were .85 and .88, respectively.
Attitude. In the proposed study attitude refers to a person’s feeling of
favorableness or unfavorableness toward drinking milk and soft drink daily. The Attitude
toward Milk Intake and Soda Pop Intake Scales consist of 4 VAS items each. Participants
were asked to place a sign (X) on a 100 mm horizontal line. The 3 items are ‘For me
drinking 3 cups of milk/drinking soda pop every day is,’ with bipolar response adjectives
as ‘Very unimportant/Very important,’ and ‘Very bad/Very good,’ and ‘Very
unenjoyable/Very enjoyable.’ The fourth item is ‘How much do you like milk?’ and
‘How much do you like soda pop?’ with responses as ‘Not at all/A lot.’ The total scores
from the Attitude scales can range from 0 to 400 with higher scores indicating more positive attitude toward milk and soda pop intake. The Cronbach’s alpha for the Attitude
toward Milk Intake and Soda Pop Intake Scales were .82 and .80, respectively.
Subjective norm. This concept refers to one’s perception of what significant others
desire concerning the performance or nonperformance of a certain behavior. It was
measured by the Subjective Norm to Milk Intake and Soda Pop Intake Scales which
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contain the following two items: ‘My friends think that I should drink 3 cups of
milk/soda pop every day’ and ‘My friends drink 3 cups of milk/soda pop every day’ with
bipolar adjective responses as ‘Strongly disagree/Strongly agree.’ The total scores on
each scale can range from 0 to 200 with higher scores indicating stronger beliefs among
one’s friends about milk and soda pop intake. The Cronbach’s alpha for the Subjective
Norm to Milk Intake and Soda Pop Intake Scales were .57 and .56, respectively.
Perceived behavioral control. PBC reflects how easy or difficult it is for someone to drink 3 cups of milk or soft drink daily. This concept was measured by the following four items in the Perceived Behavioral Control over Milk Intake and Soda Pop Intake
Scales: ‘For me drinking 3 cups of milk/soda pop every day would be,’ ‘I can decide whether or not I drink 3 cups of milk/soda pop every day,’ ‘How much control do you think you have over drinking 3 cups of milk/soda pop every day?’ and ‘Do you always get to choose what to drink at home?’ The bipolar adjective responses to the respective items are ‘Very difficult/Very easy,’ ‘Strongly disagree/Strongly agree,’ ‘No control/Complete control’ and ‘Definitely no/Definitely yes.’ The total possible scores on each scale can range from 0 to 400 with higher scores indicating stronger perception of control over drinking milk/soda pop. The Cronbach’s alpha for the Perceived Behavioral
Control over Milk Intake and Soda Pop Intake Scales were .50 and .66, respectively.
Behavioral beliefs. These are beliefs about the likely outcomes of the behavior and the evaluations of these outcomes and are one of the salient beliefs which are main determinants of intentions and actions. They were measured by three behavioral beliefs about taste, health, and weight gain and their outcome evaluations. The following are the items: ‘Drinking milk/soda pop makes be healthy,’ ‘Milk/soda pop tastes,’ ‘Drinking
81 milk/soda pop makes me gain weight,’ ‘For me being healthy is,’ ‘For me taste of milk/soda pop is,’ ‘For me gaining weight is.’ The bipolar response adjectives are
‘Strongly disagree/Strongly agree,’ ‘Very unimportant/Very important’ and ‘Very bad/Very good.’
Normative beliefs. These are the second salient beliefs about the normative expectations of others and motivation to comply with these expectations. They were measured by three items about perception of what someone in one’s family thinks about both behaviors and compliance with that person’s thoughts: ‘Someone in my family thinks I should drink 3 cups of milk/soda pop every day,’ ‘When it comes to drinking milk/soda pop, I want to do as this person in my family thinks I should’ and ‘When it comes to drinking milk, I want to do as my friends think I should. The bipolar adjective responses to the respective items are ‘Strongly disagree/Strongly agree,’ ‘Never/Always,’ and ‘Not at all/Very much.’
Control beliefs. These are the third salient beliefs which refer to the presence of factors facilitating or impeding behavioral performance and the perceived power of these factors in behavioral performance. These were measured by six items for milk and for soda about availability of milk/soda pop at home and school. The items are as follows: ‘Is there milk/soda pop in your home refrigerator?’ ‘Having milk/soda pop in our home refrigerator would make it easier for me to drink 3 cups/it every day,’ ‘My parents offer me milk/soda pop with meals and snacks,’ ‘Being offered milk by my parents would make it easier for me to drink 3 cups every day,’ ‘Do you drink milk/soda pop at school?’ and ‘Having milk/soda pop available at school would make it easier for me to drink 3 cups/it every day.’ The bipolar adjective responses to the items are ‘Never/Always,’
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‘Strongly disagree/Strongly agree,’ and ‘Definitely no/ Definitely yes.’ Each pair of
underlying influencing factors (behavioral beliefs/outcome evaluation, normative
beliefs/motivation to comply, and control beliefs/perceived power) was multiplied and
product scores were obtained for behavioral beliefs underlying attitude, normative beliefs
underlying subjective norms, and control beliefs underlying perceived behavioral control
(Ajzen, 1988, 1991).
Covariates
Gender. The gender of the participants was categorized as male or female and was
recorded on the demographic characteristics form by the participants.
Ethnicity. The participants indicated one of the following categories on the
demographic characteristics form: American Indian or Alaskan Native, Asian, Black or
African American (not of Hispanic Origin), Hispanic or Latino, Native Hawaiian or Other
Pacific Islander, and White or Caucasian (not of Hispanic Origin).
Body mass index. The BMI percentile indicates the relative position of the child’s
BMI number among children of the same sex and age. BMI, as a measure of adiposity
and body size, was operationalized using the free CDC child and teen calculator (CDC,
2006) for which child’s date of birth, date of measurement, gender, height, and weight are
required. For children who had been in to see their KP provider within three months of
the data collection letter, we planned to use the height and weight data obtained from the
record or Epic. Because of how quickly children at this age grow, we hesitated to use KP data that was older than three months. Our first approach with data collection was to obtain as many of these children as possible. In the event that we needed to rely on family obtained data due to insufficient measures from the existing data, we sent instructions in
83
which the child’s height, weight, and date of measurement were sought from the
parent/guardian who provided informed consent. In addition, date of birth and gender
were recorded by the participant on the demographic characteristics form.
BMI-for-age percentile was categorized as follows: between 5th and < 85th percentile (healthy weight), between 85th and < 95th percentile (at risk of overweight), ≥
95th percentile (overweight). We anticipated not obtaining sufficient subjects in the
underweight and overweight category. Thus, we planned to dichotomize the BMI-for-age
into two categories: healthy weight and at risk of overweight if there were insufficient
subjects in the underweight and overweight categories.
Body mass index, waist circumference, and skin-fold thickness are the most
common noninvasive measures used to define obesity (Kiess et al., 2001). Despite the
reported limitations of the BMI method, most of the reported studies on childhood obesity are based on this measure. Both lean mass and fat mass are highly correlated with
BMI, to the extent that it can act as a proxy for both, but can distinguish neither (Wells,
2001). It has been used extensively in studies because it lends itself to easy calculation in a clinical setting and correlates well with other measures of body fat such as subcutaneous and total body fat (Pietrobelli et al., 1998; Rosner et al., 1998). The validation of BMI as a measure of adiposity among children has been done in relation to total body fat (TBF) and percent of body weight as fat (PBF) estimated by dual energy x- ray absorptiometry (DXA). BMI has been shown to be strongly associated with TBF (r =
0.85 and 0.89 for boys and girls respectively) and PBF (r = 0.63 and 0.69 for boys and
girls respectively) (Pietrobelli et al., 1998). The instructions sent to parents included how
to calibrate the family scale using a known weight such as 10 pound pet food, five pound
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bags of flour or sugar, or one gallon of milk (8.5 pounds). The instructions asked to
adjust the knob on the scale until the weight on dial reads the weight of the milk, bag of
sugar or flour, or pet food.
Procedure
Approval to conduct the pilot study was obtained from the Case Western Reserve
University Institutional Review Board (IRB). For the main study, approval was obtained
from the KPO IRB and the Case Western Reserve University IRB. Written consent was
obtained from the parents/guardians, and written assent from the participants.
Pilot study
This was a “participating” pretest that is the participants were told that this is a
practice run and that after completion, their feedback concerning their reactions to the
questions and answers will be sought (Converse & Presser, 1986). There were 10
participants in the pilot study who were from two groups: (1) six children who are
personal acquaintances of the investigator such as children of fellow doctoral students
from the FPB School of Nursing at Case Western Reserve University and some of their
friends and (2) four children from a church in Cleveland. For the first group, the
investigator contacted her fellow doctoral students by phone and explained to them the
nature of the study and that it only entailed testing of questionnaires about milk and soda
pop intake developed for this study. Furthermore, a colleague of the investigator
contacted the parents of her children’s friends by phone and explained to them the nature
of the study and that it only entailed administration and testing of questionnaires during
their children’s gathering. Children of all interested parents/guardians were invited to a
colleague’s house for a gathering. For the second group, the investigator contacted
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parents of the children from the church by phone and similarly explained to them what
the study entails. Data collection took place in a Sunday school classroom in the church
with children of all interested parents and participants. Prior to data collection with both
groups, the investigator secured written consent from one parent/guardian of each child
and written assent from the children. All parents were given the choice to stay with their
children during data collection, but none did. The investigator explained to the
participants how to fill in the questionnaires by examples and asked them to individually
complete them. The participants were also allowed to ask questions at any time. After
completion of all questionnaires, all the participants as a group were asked an open ended
question. After providing responses, they were offered a healthy meal.
Main study
A packet containing the following items was mailed to the parent(s)/legal
guardians of the children: a self-addressed stamped envelope, a cover letter explaining about the study, two copies of a parent informed consent document (ICD), a copy of the child assent form, a copy of the questionnaires, instructions for height and weight measurement, a paper measuring tape that is currently used in provider practices and hospitals, and one U.S. dollar in cash as an incentive. All those who agreed their child to participate in the study were asked to sign the written informed consent form and have their child sign the written assent form. The parents were asked to measure their child’s height with the measuring tape and weigh their child following the instructions sent to them. They were asked to record the child’s height and weight on the parent ICD, have their child fill out the measures, and mail a copy of the signed ICD, the signed child assent form, and the measures in the self-addressed stamped envelope within one week.
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The parents were to keep a copy of the consent form. All those who failed to return the envelope within a week were reminded by a letter to consider the study and they were referred to the principal investigator (PI) for any concern they may have had. The PI clarified the definition of each outcome behavior in the description of the study. She provided the participants with detailed written instructions about how to fill out the questionnaires with an illustrated example in them. Anyone who had questions was instructed to contact the PI by phone. The returned questionnaires were matched with the demographic data form and the 24-hour dietary recall by subject code numbers.
Data analysis
The data analysis consisted of three parts: description, preliminary analysis, and analysis of research questions. Prior to data analysis, reliability of the questionnaires of this study was tested using internal consistency reliability by Cronbach’s alpha. The data were analyzed using the Statistical Package for the Social Science (SPSS) 16.
Description
Descriptive statistics such as frequencies, means, medians, and standard deviations were used to describe the sample characteristics and the dependent variables.
Furthermore, ranges and means of the samples’ eating behaviors in terms of patterns of milk intake and soft drink intake are provided.
Preliminary analysis
Prior to analysis, the data were examined for missing values and outliers. Any value two standard deviations away from the mean was to be considered as outlier and was to be investigated further. Assumptions of multiple regression were examined to ensure that they were not violated and to ensure proper use of parametric statistics.
87
Linearity of the relationship between the independent and the dependent variable was assessed by examining the bivariate and residual scatterplots (Mertler & Vannatta, 2002).
Data from the descriptive statistics were screened and examined for normality. Normal distribution was evaluated by examining histograms, P-P plots, and values of skewness for each variable. In case of presence of outliers, data analysis was to be performed with and without the outliers. Homoscedasticity of the variance of the residuals was also evaluated by examining the residual scatterplots for even distribution of points across the reference line (Tabachnick & Fidell, 2001). In addition, Tolerance and Variance Inflation
Factor (VIF) were examined to determine muticollinearity. If the initial residual scatterplots were not to give satisfactory results, appropriate data transformation for one or more variables was to be considered (Tabachnick & Fidell, 2001). Examining the assumption of zero mean was done by determining a constant in the equation and by checking the mean and the standard deviation of the standardized residuals which should be 0 and approximately 1, respectively. Finally, independence was evaluated by examining the Durbin-Watson statistics.
Analysis of research questions
1. Does intention about milk/soft drink intake and perceived behavioral control
influence behavior about milk/soft drink intake in school-age children?
2. Does attitude toward the behavior, subjective norm, and perceived behavioral control influence intention about milk/soft drink intake in school-age children?
3. Do behavioral beliefs about milk/soft drinks influence attitude toward milk/soft
drink intake in school-age children?
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4. Do normative beliefs about milk/soft drinks influence subjective norm about
milk/soft drink intake in school-age children?
5. Do control beliefs about milk/soft drinks influence perceived behavioral control
about milk/soft drink intake in school-age children?
Separate multiple regression analyses were run for the milk and soda data to answer research questions one through five. The following variables were used to examine how
well intention and milk intake and soft drink intake behaviors could be predicted from the
variables suggested by the TPB: (1) the dependent variables milk and soda intake
behaviors were regressed onto the independent variables intention and perceived
behavioral control, and (2) the dependent variable intention was regressed onto the
independent variables attitude, subjective norm, and perceived behavioral control.
Attitude was regressed on the product of behavioral beliefs and outcome evaluations.
Subjective norm was regressed on the product of normative beliefs and motivation to
comply with referents. Perceived behavioral control was regressed on the products of
control beliefs and perception of ease/difficulty of factors.
6. Are there differences by gender on behavioral beliefs, normative beliefs, control
beliefs, attitude, subjective norms, perceived behavioral control, intention and
behavior about milk/soft drink intake in school-age children?
7. Are there differences by ethnicity on behavioral beliefs, normative beliefs, control
beliefs, attitude toward the behavior, subjective norm, perceived behavioral
control, intention and behavior about milk/soft drink intake in school-age
children?
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8. Are there differences by BMI on behavioral beliefs, normative beliefs, control
beliefs, attitude toward the behavior, subjective norm, perceived behavioral
control, intention and behavior about milk/soft drink intake in school-age
children?
Research questions 6 through 8 were analyzed using a series of independent samples t-tests to test for differences in each variable based on gender and ethnicity. The
Bonferroni correction procedure will be used to adjust the alpha level of .05 with each
test. Because we did not obtain sufficient subjects in the Asian, African American,
Hipanic/Latino, and Native Hawaiian categories as compared the White or Caucasian
category (2 Asians, 20 African Americans, 2 Hipanic/Latino, 1 Native Hawaiian, and 72
White/Caucasian), we opted to collapse the categories with small distributions and
dichotomized the ethnicity variable into Minority and White or Caucasian and ran
analyses with two categories.
Research question number 8 was planned to be analyzed using analysis of variance
(ANOVA) to test for differences in BMI-for-age for weight status categories [between 5th
and < 85th percentile (healthy weight), between 85th and < 95th percentile (at risk of
overweight), ≥ 95th percentile (overweight)]. The Scheffé post-hoc test, as the most
conservative one among the post-hoc tests, was to be used to simultaneously test the
multiple comparisons of the various groups. However, similar to the ethnicity variable,
we did not obtain sufficient subjects in the three categories (12 Overweight, 26 At risk of
overweight, Vs 59 Healthy weight). Consequently, we opted to collapse the overweight
category with small distribution into the At risk of overweight category and dichotomized
the BMI-for-age weight status categories and ran a series of independent samples t-tests
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to test for differences in each variable based on Healthy weight and At risk of overweight
categories.
Protection of human subjects
The selection process in this study ensured fair selection that is, without specific
exclusion or inclusion of individuals based on gender, race, ethnicity, cultural, or social
values. All children from the selected list were eligible for the study. All subjects were
treated similarly with no discrimination. All parents of subjects participating in this study
were required to provide written informed consent. While the study population is
considered legally incompetent to give informed consent, children were asked to give
their written assent.
This study entailed only minimal risk consisting of a possible emotional discomfort
for some of the participants due to measurement of height and weight. To maintain
confidentiality of the data and to mask participants’ identity, data were coded with study-
specific identification numbers. The raw data will be kept in a cabinet, in a locked office for three years after the completion of the study. Only the investigator and her faculty advisor will have access to the data.
Because this study entailed only minimal risk, consent from only one parent/legal guardian was sufficient. Consent was obtained concurrently with enrollment in the study and was to be sought again in case any changes in the study procedures occurred. The consent/assent process included: (1) an explanation of the purpose and the nature of the study; (2) a clear statement of the potential risks/benefits of the study; (3) ensuring all
participants’ the right to privacy and confidentiality; (4) explanation of compensation;
and (5) ensuring a non-coercive nature of the study and the right to withdraw at any
91 point. A copy of the informed consent and assent was provided to the participant and parent/legal guardian, while another copy is kept with the investigator. Approval to conduct the study was sought from the IRBs at KPO and Case Western Reserve
University.
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CHAPTER IV
Results
The results from this study will be presented in this chapter. The purposes of this study were to: (1) determine influences on school-age children’s milk and soft drink
intake and (2) determine the effect of gender, ethnicity, and BMI on behavioral beliefs,
normative beliefs, control beliefs, attitude toward the behavior, subjective norm,
perceived behavioral control, intention, and behaviors about milk/soft drink intake in
school-age children.
Of the total surveys mailed to 600 participants from October to December 2007, ninety eight completed surveys were returned by May 2008. One had considerable missing information and was excluded from the study. Thirty packets were returned as undeliverable mail and 4 unsigned consent forms were returned with notes about lack of participation because child was 12 years old. Thus there was complete data on 97 participants, yielding a response rate of 16%. Of the 97 respondents, three were allergic
to milk and three were not allowed to drink soda. These participants did not respond to
the Milk Intake Questionnaire and Soda Pop Intake Questionnaire respectively.
This chapter presents description of the demographic characteristics of the sample,
the patterns of milk and soft drink intake, and the study variables. In addition, results
from the preliminary analyses of statistical assumptions and analyses to answer the
research questions will be presented.
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Description
Demographic characteristics
The demographic characteristics of the study participants are presented in Table 5.
The study sample consisted of school-age children (N=97). The gender distribution was similar with slightly over half of the participants being female (54%). The ages ranged from 10 to 12 with a mean of 11 years (SD = .64). Despite the fact that Greater
Cleveland’s population is approximately 51% African American, the majority of the participants were White or Caucasian (74%), followed by Black or African American
(21%). There were no American Indians or Alaskan Natives, and only 2 Asians (2%), 2
Hispanics (2%), and 1 Native Hawaiian (1%). The majority of the participants lived with both parents (86%). Eleven percent lived with mother only. One participant lived with grandmother and grandfather. Two participants (2%) in the ‘Other’ category lived with father and stepmother. None lived with father only, grandmother only, or grandfather only. The majority of the participants (61%) had a healthy weight, followed by 27% being at risk of overweight and 12% being overweight.
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Table 5.
Frequencies of demographic characteristics of the study sample
Characteristics N %
Age (in years) 10 35 36 11 49 51 12 12 12 Gender Male 45 46
Female 52 54
Ethnicity American Indian or Alaskan Native - - Asian 2 2 Black or African American (not of Hispanic origin) 20 21 Hispanic or Latino 2 2 Native Hawaiian or Other Pacific Islander 1 1 White or Caucasian (not of Hispanic origin) 72 74 Who the child lives with Mother & father 83 86
Mother only 11 11 Grandmother & grandfather 1 1
Other 2 2 Father only - -
Grandmother only - -
Grandfather only - - BMI -for-age weight status category Healthy weight 59 61 At risk of overweight 26 27
Overweight 12 12
Description of eating behaviors and patterns of milk and soft drink intake
The patterns of milk and soft drink intake of the study participants are presented in Table 6. The data gathered about the eating behavior covers a 24-hour period. The majority of the respondents (86%) claimed to have had breakfast the morning they completed the questionnaire. Seventy two percent had breakfast at home, followed by
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13% at school. A considerable number of respondents (36%, n= 35) did not drink milk during breakfast but the majority did (64%, n= 62). To obtain an estimate of total milk consumption per regular school day, we asked respondents to indicate both in glasses and cartons. We considered an 8-ounce carton similar to an 8-ounce glass and so we added them with equal weights. Half the sample (48%, n= 46) responded up to two glasses, followed by 3 glasses (20%, 20), and more than 3 glasses (26%, n= 25). Only six percent did not drink milk.
Almost all (99%) respondents had lunch the day prior to responding, and the majority (73%) had it at school, followed by 22% who had it at home. Half of the respondents (53%) got their lunch from home and 28% got it at school. The rest (16%) bought it and only 2 respondents (2%) got it from friends.
The majority (93%) had dinner, of which 90% had it at home. As expected at this age, 68% of respondents claimed family preparing meals and 32% claimed both family and themselves preparing meals. The majority (83%) had dinner with family, 11% with others, and only 6% ate alone.
There were twice as many consumers of soft drinks than nonconsumers (71%, n=
69 and 29%, n= 28 respectively). To obtain an estimate of total soda consumption on a usual school day, we asked respondents to indicate in cans, cups, and bottles. We coded a
12-ounce can as 1 and weighted the 16-ounce cup and bottle as 1.45. We added the values across the three measures of soda and came up with an estimate of number of cans/day. These figures yielded the following results about the amount of soda consumption during a school day: 41% drank none, followed by 27% claiming one can,
23% two to three cans, and 6% more than 3 cans. The nonconsumers of soda (41%) were
96 different than the ones (29%) in the previous question. This is because the question for the latter result had no time context to it, whereas the prior question had a clear time context: on a usual day during the school week. Less than half (40%) reported drinking milk with snacks and only 19% claimed to drink soda with snacks. When asked when given the choice, what respondents would choose to drink, the majority (45%) chose water, followed by 26% milk and 10% soda. Of the 16% that chose the “Other” category,
41% preferred juice (orange juice and lemonade) and one respondent preferred milk shake.
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Table 6.
Frequencies of eating behaviors and patterns of milk and soft drink intake
Variable N %
Ate anything before school in the morning Yes 83 86 No 14 14 Where child ate morning food Home 70 72 School 12 13 Car 3 3 Another place 3 3 Did not eat anything 9 9 Drank milk before school in the morning Yes 62 64 No 35 36 On a usual school day how much milk child drinks None 6 6 Up to 2 glasses 46 48 3 glasses 20 20 >3 glasses 25 26 Ate lunch the day before Yes 96 99 No 1 1 Where child ate lunch Home 21 22 School 71 73 Another place 5 5 Did not eat lunch - - Where child got lunch from Bought it 16 16 Home 51 53 Friends 2 2 School 27 28 None 1 1 Had meal after school and before bedtime (dinner) Yes 90 93 No 7 7 Where child ate dinner Home 87 90
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Table 6 (continued).
Variable N %
Another place 3 3 Did not eat anything before 7 7 Who prepares food at home My family 66 68 Me - - My family and me 31 32 Other people - - Had food last night With family 80 83 With others 10 11 By myself 6 6 Does child drink soda pop Yes 69 71 No 28 29 On a usual school day how much soda pop child drinks None 40 41 One can 26 27 2-3 cans 23 23 >3 cans 6 6 On a typical school day what child would choose to drink Soda pop 10 10 Milk 25 26 Water 44 45 Nothing 1 1 Other 16 17 On a usual school day does child drink milk with snacks Yes 39 40 No 58 60 On a usual school day does child drink soda pop with snacks Yes 18 19 No 79 81 Note. Percentages may not equal 100 due to missing values.
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Description of study variables
As shown in Table 7, the respondents had neutral to probable intention to drink 3
cups of milk daily (M = .42, SD = 2.5, range -4 to +4); however, they had negative
intention to drink soda pop every day (M = -2, SD = 2.3). For attitude, the range of
responses was 0 to 400. They had moderately positive attitude towards drinking 3 cups of
milk daily (M = 250, SD = 85) and moderately negative attitude toward drinking soda
pop every day (M = 178.7, SD = 82.7). For subjective norm, the scale ranged from 0 to
200. They slightly disagreed that their friends think they should drink 3 cups of milk
daily (M = 87, SD = 48.3) and moderately disagreed that their friends think they should
drink soda pop every day (M = 66, SD = 41.6). For perceived behavioral control (range 0
to 400), they perceived drinking 3 cups of milk per day as moderately easy and that they
had moderate control over the behavior (M = 284, SD = 68). The perception of drinking soda was similar to that of milk intake but was slightly easier and they had slightly less control over the behavior (M = 229, SD = 100). The average consumption of milk was 3 glasses/day (SD = 2.42) and that of soda was 1.5 cans/day (SD = 2.5).
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Table 7.
Summary of descriptive statistics of the study variables
Variable N Mean SD Possible Skewness range Milk subscales Behavioral Intention to drink milk 93 .42 2.5 -4 - 4 -.41 Attitude toward milk intake 93 250 85 0-400 -.52 Subjective norm to milk intake 93 87 48.3 0-200 .20 Perceived behavioral control 93 284 68 0-400 0 Milk intake behavior (glasses) 97 3 2.42 - 2.1 Soda pop subscales Behavioral Intention to drink soda 92 -2 2.3 -4 - 4 1 Attitude toward soda intake 89 178.7 82.7 0-400 -.21 Subjective norm to soda intake 92 66 41.6 0-200 .4 Perceived behavioral control 93 229 100 0-400 -.21 Soda intake behavior (cans) 95 1.5 2.5 - 4.1
Preliminary analysis
Prior to analysis, the data were examined for missing values and outliers. The missing values were minimal and random. Consequently, no imputations were needed.
Using the standardized deleted residuals and leverage values, no values were found two standard deviations away from the mean, suggesting absence of outliers. Outliers may or may not affect the estimation of a regression line; however, if they do so, they are called influential cases (Tabachnick & Fidell, 2001). Cook’s Distance of all the independent variables was < 1, indicating the absence of influential data points.
The following assumptions of multiple regression were examined to ensure that they were not violated and to ensure proper use of parametric statistics: (1) zero mean;
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(2) independence; (3) normal distribution of residuals; (4) homoscedasticity; (5)
multicollinearity; and (6) linearity of the relationship between the independent and the
dependent variable. Zero mean and independence are two assumptions that cannot be
violated for multiple regression. The assumption of zero mean was met by determining a
constant in the equations and by checking the mean and the standard deviation of the
standardized residuals which were 0 and 1, respectively, for the milk and the soda
variables. Independence was evaluated by examining the Durbin-Watson statistic which
was 2.100 for the milk variables and 1.992 for the soda variables. These values were not
> 2.5 and < 1.5, indicating no violation of this assumption.
Data from the descriptive statistics were screened and examined for normality.
Normal distribution was evaluated by examining histograms, P-P plots, and values of
skewness for each variable. The shape of the histograms indicated normal distribution
and the P-P plots were close to straight lines. Homoscedasticity of the variance of the
residuals was also evaluated by examining the residual scatterplots for even distribution
of points across the reference line (Tabachnick & Fidell, 2001). This assumption was not
violated since there was an approximately even random scatter of values across the
reference line. Multicollinearity was examined by checking the tolerance and VIF for both the milk and soda variables. All milk and soda independent variables had Tolerance values >.10 and VIF <10, indicating no multicollinearity. Finally, the assumption of linearity was also met. The bivariate and residual scatterplots revealed linear relationships between the independent and the dependent variables.
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Analysis of research questions
The Theory of Planned Behavior constructs
Separate multiple regressions were run to answer research questions one through
five. The results of the 5 multiple regression analyses for explanation of milk intake are
presented in Figure 4 and that of soda intake are presented in Figure 5.
1. Does intention about milk/soft drink intake and perceived behavioral control
influence behavior about milk/soft drink intake in school-age children?
Milk data. In explaining milk intake behavior among school-age children, both intention and perceived behavioral control were positively related to milk intake; however, only intention had a statistically significant positive correlation with milk intake
(r =.24, p = .01). These two independent variables together explained 4% of the variance in milk intake. The overall regression equation was statistically significant (F = 2.95, p
=.05). Only intention predicted milk intake (β = .26) and was statistically significant (t =
2.43, p = .02), with stronger intention to drink milk being more related to actual milk
intake. Perceived behavioral control was not a significant predictor of milk intake (t = -
.54, p = .59).
Soft drink data. In explaining soft drink intake behavior among school-age
children, similar to the milk intake results, both intention and perceived behavioral
control were positively related to soda intake; however, only intention had a statistically significant positive correlation with soda intake (r =.39, p < .0001). These two
independent variables together explained 14% of the variance in soda intake. The overall
regression equation was statistically significant (F = 8.18, p = .001). Similar to milk
intake results, only intention to drink soft drink predicted soft drink intake (β = .42) and
103 was statistically significant (t = 3.83, p < .0001), with stronger intention to drink soda being more related to actual soda intake. Perceived behavioral control was not a significant predictor of soft drink intake (t = -.54, p = .59).
2. Does attitude toward the behavior, subjective norm, and perceived behavioral
control influence intention about milk/soft drink intake in school-age children?
Milk data. Attitude, subjective norm, and perceived behavioral control had moderate to high statistically significant positive relationships with intention to drink milk (r =.69, p < .0001, r =.37, p < .0001, and r =.28, p = .003 respectively); however, all these relationships did not hold when they were assessed independently in a multiple regression analysis. The three independent variables yielded a good level of prediction and together explained 49% of the variance in intention to drink milk. However, attitude was the only significant independent predictor (β = .64) of intention to drink milk (t =
7.48, p < .0001), with more positive attitude towards milk intake being associated with stronger intention to drink milk. The overall regression equation was statistically significant (F = 30.55, p < .0001). Subjective norm and perceived behavioral control were not significant predictors of milk intake (t = .93, p = .36 and t = 1.66, p = .10 respectively).
Soft drink data. Attitude, subjective norm, and perceived behavioral control had moderate to high statistically significant positive relationships with intention to drink soda (r =.59, p < .0001, r =.39, p < .0001, and r =.47, p < .0001 respectively); however, all these relationships did not hold when they were assessed independently in a multiple regression analysis. The three independent variables yielded a good level of prediction and together explained 44% of the variance in intention to drink soft drink. Attitude and
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perceived behavioral control were significant independent predictors (β = .45 and β = .30 respectively) of intention to drink soda (t = 4.96, p < .0001 and t = 3.53, p = .001 respectively) with attitude being the stronger predictor. More positive attitude towards soda intake and stronger perceived behavioral control were associated with stronger intention to drink soda. The overall regression equation was statistically significant (F =
23.04, p < .0001). Similar to the milk intake results, subjective norm was not a significant predictor of intention to drink soda (t = 1.43, p = .16).
3. Do behavioral beliefs about milk/soft drinks influence attitude toward milk/soft
drink intake in school-age children?
As attitudes were strong predictors of both intention to drink milk and soft drink, the importance of the underlying beliefs of the attitudes were examined using multiple regression analyses. See Figures 4 and 5 for the regression results.
Milk data. Regressions of attitude towards milk intake onto the behavioral beliefs accounted for 45% of the variability. The overall regression equation was statistically significant (F = 26.39, p < .0001). Being healthy by drinking milk and taste of milk had high statistically significant positive associations with attitude to drink milk (r =.48, p <
.0001, and r =.65, p < .0001 respectively). These relationships remained when they were assessed independently in a multiple regression analysis. Both being healthy and taste were significant independent predictors of attitude (t = 2.75, p = .007 and t = 6.28, p <
.0001 respectively) with taste being the stronger predictor (β = .55) than being healthy (β
= .24). The participants thought that drinking milk makes them healthy and taste was important for their choice of drinking milk. The third belief that drinking milk makes one
105 gain weight had no independent influence in predicting attitude toward milk intake (t =
1.13, p = .26).
Soft drink data. Regressions of attitude towards soft drink intake onto the behavioral beliefs accounted for 52% of the variability. The overall regression equation was statistically significant (F = 31.53, p < .0001). Similar to the milk intake beliefs, being healthy by drinking soft drink and taste of soft drink had moderate to high statistically significant positive associations with attitude to drink soft drink (r =.42, p <
.0001, and r =.67, p < .0001 respectively). These relationships remained when they were assessed independently in a multiple regression analysis. Both being healthy and taste were significant independent predictors of attitude toward drinking soda (t = 3.82, p <
.0001 and t = 7.92, p < .0001 respectively) with taste being the stronger predictor (β =
.61) than being healthy (β = .29). Similarly, the participants thought that drinking soda makes them healthy and taste was important for their choice of drinking soda. The third belief that drinking soda makes one gain weight had no independent influence in predicting attitude toward soft drink intake (t = 1.29, p = .20).
4. Do normative beliefs about milk/soft drinks influence subjective norm about
milk/soft drink intake in school-age children?
Milk data. The two independent variables (normative beliefs) yielded a good level of prediction and together explained 60% of the variance in subjective norms to milk intake. The overall regression equation was statistically significant (F = 70.88, p <
.0001). Both someone in one’s family and friends had moderate to high positive significant correlations with subjective norm (r =.31, p = .001, and r =.78, p < .0001 respectively). These associations were stronger for friends than family member. Unlike
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the correlation coefficients, only friends was an independent significant predictor (β =
.84) of subjective norm (t = 10.93, p < .0001), with participants wishing to comply more
with what friends think they should be doing in terms of drinking milk than what
someone in the family thinks.
Soft drink data. The two independent variables (normative beliefs) yielded a
moderate level of prediction and together explained 30% of the variance in subjective
norms to soft drink intake. The overall regression equation was statistically significant (F
= 20.23, p < .0001). Both someone in one’s family and friends had positive significant
correlations with subjective norm (r =.32, p = .001, and r =.56, p < .0001 respectively).
Similar to the milk data results, these associations were stronger for friends than family member; however, the association between friends and subjective norm was slightly weaker than the one obtained in the milk data (r =.78, p < .0001). Unlike the correlation
coefficients, only friends was an independent significant predictor (β = .55) of subjective
norm (t = 5.20, p < .0001), with participants wishing to comply more with what friends
think they should be doing in terms of soft drink intake.
5. Do control beliefs about milk/soft drinks influence perceived behavioral control
about milk/soft drink intake in school-age children?
Milk data. The three independent variables (control beliefs) yielded a fair level of
prediction and together explained 14% of the variance in perceived behavioral control to
drink milk. The overall regression equation was statistically significant (F = 6.18, p =
.001). Only availability of milk in home refrigerator had a moderate statistically
significant positive association with perceived behavioral control to drink milk (r = .41, p
< .0001) and this relationship remained when it was assessed independently in a multiple
107 regression analysis. Availability of milk in home refrigerator was the only significant independent predictor of perceived behavioral control (t = 4.24, p < .0001). The participants thought that having milk available in their home refrigerator made it easier for them to drink it. The other two beliefs about availability at school and whether being offered milk by parents made it easier for them to drink milk had no independent influence in predicting perceived behavioral control to drink milk (t = -.62, p = .54 and t
= -.02, p = .99 respectively).
Soft drink data. The three independent variables (control beliefs) yielded a fair level of prediction and together explained 8% of the variance in perceived behavioral control to drink soda. The overall regression equation was statistically significant (F =
3.40, p = .02) and unlike the milk data, all three variables: availability of soda in home refrigerator, availability at school, and being offered by parents had low to moderate statistically significant positive associations with perceived behavioral control to drink soda (r =.28, p = .004, r =.20, p = .03, and r =.19, p = .04 respectively). However, none of these relationships remained when they were assessed independently in a multiple regression analysis. None of the control beliefs about availability of soda in home refrigerator, availability at school, and whether being offered soda by parents made it easier for them to drink it had significant predictions of perceived behavioral control to drink soda (t = 1.89, p = .06, t = 1.35, p = .18, and t = .89, p = .38 respectively).
Figure 4. Path diagram for explanation of milk intake
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Figure 5. Path diagram for explanation of soft drink intake
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Gender, ethnicity, and BMI differences
6. Are there differences by gender on behavioral beliefs, normative beliefs, control
beliefs, attitude, subjective norms, perceived behavioral control, intention and
behavior about milk/soft drink intake in school-age children?
The results of independent samples t tests revealed no statistically significant differences between males and females in terms of the milk and the soda pop TPB variables and both behaviors. The results are presented in Table 8. The scores of the behavioral beliefs, normative beliefs, and control beliefs are large. The reason for this is that each pair of underlying influencing factors (behavioral beliefs/outcome evaluation, normative beliefs/motivation to comply, and control beliefs/perceived power) was multiplied and product scores were obtained for behavioral beliefs underlying attitude, normative beliefs underlying subjective norms, and control beliefs underlying perceived behavioral control.
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Table 8.
Gender differences in the milk and soda pop variables
Variable Gender n Mean SD Possible t range Milk variables Behavioral Intention Male 45 .56 2.37 -4 - 4 .52 Female 48 .29 2.55 -4 - 4 Attitude Male 45 247.33 84.07 0-400 -.30 Female 48 252.63 86.53 0-400 Behavioral beliefs: Milk makes me healthy Male 45 7036.29 2850.18 0-10,000 -.28 Female 48 7194.88 2643.10 0-10,000 Milk taste Male 45 4679.78 2850.31 0-10,000 -.65 Female 48 5067.43 2859.76 0-10,000 Milk makes me gain weight Male 45 1144.77 1835.56 0-10,000 .16 Female 48 1090.29 1456.53 0-10,000
Subjective norm Male 45 82.42 46.33 0-200 -.91 Female 48 91.56 50.13 0-200 Normative beliefs: Someone in family Male 45 4924.60 3248.31 0-10,000 1.15 Female 48 4177.75 3027.06 0-10,000 Friends Male 45 2951.73 2511.82 0-10,000 -.71 Female 48 3363.38 3056.83 0-10,000
Perceived behavioral control Male 45 289.40 74.33 0-400 .78 Female 48 278.27 61.53 0-400 Control beliefs: Milk in home refrigerator Male 45 6967.84 2938.81 0-10,000 -.67 Female 48 7393.4792 3181.61 0-10,000 Milk at school Male 45 4823.22 3652.84 0-10,000 .46 Female 48 4464.98 3894.72 0-10,000 Parents offering Male 45 3125.80 2827.27 0-10,000 -.33 Female 48 3335.65 3276.68 0-10,000
Milk intake behavior (glasses) Male 45 3.41 2.74 - 1.35 Female 52 2.75 2.09 - Soda pop variables Behavioral Intention Male 43 -1.91 2.41 -4 - 4 .40 Female 49 -2.10 2.24 -4 - 4
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Attitude Male 42 188.24 81.46 0-400 1.03 Female 47 170.15 83.66 0-400 Table 8 (continued).
Variable Gender n Mean SD Possible t range
Behavioral beliefs: Soda makes me healthy Male 44 1050.09 1385.38 0-10,000 .32 Female 47 961.21 1295.65 0-10,000 Soda taste Male 44 4352.98 2463.64 0-10,000 -.16 Female 49 4450.78 3325.66 0-10,000 Soda makes me gain weight Male 44 2232.45 2466.94 0-10,000 1.22 Female 47 1704.53 1581.45 0-10,000
Subjective norm Male 43 68.72 44.46 0-200 .36 Female 49 63.53 39.19 0-200 Normative beliefs: Someone in family Male 44 491.09 810.75 0-10,000 1.03 Female 49 337.35 630.85 0-10,000 Friends Male 44 940.34 1234.02 0-10,000 1.24 Female 49 659.14 938.63 0-10,000
Perceived behavioral control Male 44 241.23 104.64 0-400 1.15 Female 49 217.31 95.21 0-400 Control beliefs: Soda in home refrigerator Male 0-10,000 .43 3524.43 2958.22 44 Female 49 3246.53 3297.47 0-10,000 Soda at school Male 43 823.93 1339.83 0-10,000 1.54 Female 49 455.14 946.26 0-10,000 Parents offering Male 44 1509.57 2090.31 0-10,000 .63 Female 48 1243.33 1969.50 0-10,000
Soda intake behavior (cans) Male 44 1.46 1.95 - -.09 Female 51 1.51 2.92 -
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7. Are there differences by ethnicity on behavioral beliefs, normative beliefs, control
beliefs, attitude toward the behavior, subjective norm, perceived behavioral
control, intention and behavior about milk/soft drink intake in school-age
children?
Milk data. The results of a two-tailed independent samples t test revealed a significant difference between the races with respect to behavioral intention t (91) = -2.0, p = .05. There was a stronger disposition to drink milk among white participants (M =
.68, SD = 2.56) than the ones in the minority group (M = -.33, SD = 1.97). Similarly, a statistically significant difference was found in one behavioral belief about health t (91) =
-1.93, p = .05) where white participants perceived that drinking milk makes them healthy
(M = 7435.55, SD = 2660.13) more than the minority (M = 6205.58, SD = 2783.77).
Within the normative beliefs, white participants (M = 5031.14, SD = 3124.58) had a significantly stronger perception than the minority (M = 3124.58, SD = 2082.96) that someone in their family thinks they should drink 3 cups of milk every day t (91) = -3.27, p = .002. Within the control beliefs, white participants (M = 7581.28, SD = 3028.01) had a significantly stronger perception than the minority (M = 6055.50, SD = 2912.10) that having milk in home refrigerator would make it easier for them to drink 3 cups of milk every day t (91) = -2.15, p = .03. There were no statistically significant differences between minority and white participants in terms of the rest of the TPB variables about milk. The results are presented in Table 9.
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Soft drink data. Within the soda pop variables, differences were found in both
normative beliefs and soda intake behavior. Contrary to the milk normative belief about
family, the minority participants (M = 700.63, SD = 877.64) had a significantly stronger perception than the white participants (M = 309.03, SD = 635.57) that someone in their family thinks they should drink soda pop every day t (91) = 2.01, p = .05. Similarly, the minority participants (M = 1163.67, SD = 1237.67) had a significantly stronger perception than the white participants (M = 662.97, SD = 1013.93) that their friends think they should drink soda pop every day t (91) = 1.97, p = .05. As for the soda intake, the minority participants (M = 2.60, SD = 3.56) drank significantly more soda than the white participants (M = 1.09, SD = 1.88) t (93) = 2.65, p = .009. There were no statistically significant differences between minority and white participants in terms of the rest of the TPB variables about soda pop.
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Table 9.
Race/ethnicity differences in the milk and soda pop variables
Variable Race n Mean SD Possible t range Milk variables Behavioral Intention Minority 24 -.33 1.97 -4 - 4 -2.00* White 69 .68 2.56 -4 - 4
Attitude Minority 24 229.42 65.18 0-400 -1.39 White 69 257.25 90.10 0-400 Behavioral beliefs: Milk makes me healthy Minority 24 6205.58 2783.77 0-10,000 -1.93* White 69 7435.55 2660.13 0-10,000 Milk taste Minority 24 4903.46 2970.66 0-10,000 .05 White 69 4871.65 2824.13 0-10,000 Milk makes me gain weight Minority 24 1392.54 1692.97 0-10,000 .96 White 69 1020.70 1625.37 0-10,000
Subjective norm Minority 24 78.54 35.23 0-200 -1.01 White 69 90.13 51.96 0-200 Normative beliefs: Someone in family Minority 24 3124.58 2082.96 0-10,000 -3.27* White 69 5031.14 3306.35 0-10,000 Friends Minority 24 2453.33 2602.71 0-10,000 -1.45 White 69 3411.45 2840.28 0-10,000
Perceived behavioral control Minority 24 268.88 66.46 0-400 -1.24 White 69 288.80 68.09 0-400 Control beliefs: Milk in home refrigerator Minority 24 6055.50 2912.10 0-10,000 -2.15* White 69 7581.28 3028.01 0-10,000 Milk at school Minority 24 4216.96 3777.19 0-10,000 -.64 White 69 4784.88 3775.17 0-10,000 Parents offering Minority 24 2523.38 2566.08 0-10,000 -1.48 White 69 3481.32 3184.44 0-10,000
Milk intake behavior(glasses) Minority 25 2.56 1.35 - -1.61 White 72 3.23 2.68 -
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Table 9 (continued).
Variable Race n Mean SD Possible t range
Soda pop variables Behavioral Intention Minority 24 -1.67 2.32 .47268 .40 White 68 -2.13 2.31 .28024
Attitude Minority 21 193.33 73.96 16.13947 .36 White 68 174.16 85.17 10.32778 Behavioral beliefs: Soda makes me healthy Minority 23 1296.13 1443.95 0-10,000 1.22 White 68 905.44 1289.66 0-10,000 Soda taste Minority 24 4856.79 2997.85 0-10,000 .88 White 69 4247.19 2917.42 0-10,000 Soda makes me gain weight Minority 23 1973.91 1666.84 0-10,000 .04 White 68 1955.01 2192.04 0-10,000
Subjective norm Minority 23 73.26 35.22 0-200 .33 White 69 63.52 43.46 0-200 Normative beliefs: Someone in family Minority 24 700.63 877.64 0-10,000 2.01* White 69 309.03 635.57 0-10,000 Friends Minority 24 1163.67 1237.67 0-10,000 1.97* White 69 662.97 1013.93 0-10,000
Perceived behavioral control Minority 24 202.08 92.97 0-400 .13 White 69 237.86 101.28 0-400 Control beliefs: Soda in home refrigerator Minority 24 2858.92 2628.07 0-10,000 -.94 White 69 3558.57 3281.93 0-10,000 Soda at school Minority 24 1041.63 1414.23 0-10,000 2.08 White 68 481.35 1021.56 0-10,000 Parents offering Minority 23 2050.26 2118.47 0-10,000 1.89 White 69 1144.13 1951.33 0-10,000
Soda intake behavior (cans) Minority 25 2.60 3.56 - 2.65* White 70 1.09 1.88 - * p ≤ .05
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8. Are there differences by BMI on behavioral beliefs, normative beliefs, control
beliefs, attitude toward the behavior, subjective norm, perceived behavioral
control, intention and behavior about milk/soft drink intake in school-age
children?
The results of independent samples t tests revealed no statistically significant differences between participants in the ‘healthy weight’ category and those in the ‘at risk of overweight’ category in terms of the milk and the soda pop TPB variables and both behaviors. The results are presented in Table 10.
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Table 10.
BMI differences in the milk and soda pop variables
Variable BMI n Mean SD Possible t category range Milk variables Behavioral Intention Healthy 58 .33 2.48 -4 - 4 -.46 At risk 35 .57 2.44 -4 - 4
Attitude Healthy 58 241.14 86.39 0-400 -1.31 At risk 35 264.86 81.51 0-400 Behavioral beliefs: Milk makes me healthy Healthy 58 7173.53 2687.33 0-10,000 .25 At risk 35 7026.34 2840.09 0-10,000 Milk taste Healthy 58 4680.22 2774.26 0-10,000 -.87 At risk 35 5210.69 2972.88 0-10,000 Milk makes me gain weight Healthy 58 1287.90 1844.32 0-10,000 1.44 At risk 35 832.89 1208.09 0-10,000
Subjective norm Healthy 58 93.67 48.43 0-200 1.70 At risk 35 76.31 46.72 0-200 Normative beliefs: Someone in family Healthy 58 4552.83 3038.91 0-10,000 .05 At risk 35 4516.43 3349.56 0-10,000 Friends Healthy 58 3374.79 2807.71 0-10,000 .93 At risk 35 2815.20 2789.377 0-10,000
Perceived behavioral control Healthy 58 281.47 68.03 0-400 -.40 At risk 35 287.29 68.48 0-400 Control beliefs: Milk in home refrigerator Healthy 58 7450.03 2933.67 0-10,000 1.07 At risk 35 6752.51 3248.52 0-10,000 Milk at school Healthy 58 4427.24 3772.12 0-10,000 .60 At risk 35 4988.11 3777.28 0-10,000 Parents offering Healthy 58 3381.47 3095.37 0-10,000 -.69 At risk 35 2989.91 3009.16 0-10,000
Milk intake behavior(glasses) Healthy 60 3.10 2.62 - .22 At risk 37 2.99 2.10 -
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Table 10 (continued).
Variable BMI n Mean SD Possible t category range Soda pop variables
Behavioral Intention Healthy 57 -1.93 2.48 -4 - 4 .43 At risk 35 -2.14 2.03 -4 - 4
Attitude Healthy 53 179.47 73.88 0-400 .11 At risk 36 177.53 95.22 0-400
Behavioral beliefs: Soda makes me healthy Healthy 56 983.14 1395.09 0-10,000 -.19 At risk 35 1037.86 1246.41 0-10,000 Soda taste Healthy 57 4498.56 2634.55 0-10,000 .37 At risk 36 4255.58 3389.48 0-10,000 Soda makes me gain weight Healthy 55 2042.84 1968.09 0-10,000 .46 At risk 36 1832.92 2222.91 0-10,000
Subjective norm Healthy 56 62.00 37.05 0-200 -1.14 At risk 36 72.11 47.70 0-200 Normative beliefs: Someone in family Healthy 57 320.44 554.54 0-10,000 -1.36 At risk 36 552.03 918.24 0-10,000 Friends Healthy 57 668.6 955.08 0-10,000 -1.3 At risk 36 987.72 1268.01 0-10,000
Perceived behavioral control Healthy 57 225.04 95.22 0-400 -.43 At risk 36 234.31 108.17 0-400 Control beliefs: Soda in home Healthy 0-10,000 -.13 refrigerator 57 3345.09 3098.08 At risk 36 3430.14 3217.60 0-10,000 Soda at school Healthy 57 1216.35 1859.97 0-10,000 .14 At risk 35 1621.97 2265.61 0-10,000 Parents offering Healthy 56 641.02 1182.92 0-10,000 -.93 At risk 36 606.50 1127.59 0-10,000
Soda intake behavior (cans) Healthy 59 1.60 2.89 - .56 At risk 36 1.30 1.74 - Note. ‘Healthy’ refers to healthy weight and ‘At risk’ refers to at risk of overweight
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Summary
The purposes of this study were to: (1) determine influences on school-age children’s milk and soft drink intake and (2) determine the effect of gender, ethnicity, and
BMI on the TPB variables and behaviors about milk/soft drink intake in school-age children. Of the total surveys mailed to 600 participants from October to December 2007, ninety seven completed surveys were returned by May 2008.
For the demographic variables, slightly more than half of the participants were female (54%). The ages ranged from 10 to 12 with a mean of 11 years (SD = .64). The majority of the participants were White or Caucasian (74%). The majority of the participants lived with both parents (86%) and 11% lived with mother. Concerning the eating behaviors, the majority did drink milk during breakfast (64%, n= 62), of which
20% had 3 glasses per day. Only 6% did not drink milk. There were twice as many consumers of soft drink than nonconsumers (71%, n= 69 and 29%, n= 28 respectively).
Forty percent drank milk with snacks and 19% drank soda.
Multiple regression was used to answer research questions one through five. In
question one, only intention significantly predicted milk and soda intake. In question two,
attitude was the only significant predictor of intention to drink milk and in the soda data,
both attitude and perceived behavioral control significantly predicted intention with
attitude being the stronger predictor. For the behavioral beliefs, both behaviors, being
healthy and taste, were predictors of attitude with taste being the stronger predictor. For
normative beliefs, friends were a significant predictor of subjective norm in both
behaviors. For control beliefs, availability of milk in home refrigerator was the only
121 significant predictor of perceived behavioral control for milk. None of the control beliefs were significant predictors of soda intake.
For research questions 6 and 8, the results of independent samples t tests revealed no statistically significant gender and BMI differences in terms of the milk and the soda pop TPB variables and both behaviors. For question 7, significant differences were found between the races with respect to the milk behavioral intention, behavioral belief about health, normative belief about family, and control belief about availability of milk in home refrigerator, with white participants scoring higher in these variables. Within the soda pop variables, differences were found in both normative beliefs and soda intake behavior. The minority participants had a significantly stronger perception than the white participants that someone in their family and friends think they should drink soda pop every day. The minority participants drank significantly more soda than the white participants.
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CHAPTER V
Discussion
The beverage consumption patterns of American children have changed over the past decades. Daily milk consumption among 6 to 11-year-olds has dropped and, during the same time period, soft drink consumption has doubled, leading to potential serious health conditions (Nicklas & Hayes, 2008). Understanding eating habits of children early in life is important for planning effective intervention strategies. This cross-sectional
descriptive correlational study is the first one to use the TPB to investigate influences on
school-age children’s milk and soft drink intake in the U.S. The purposes were to: (1)
determine influences on school-age children’s milk and soft drink intake and (2) determine the effect of gender, ethnicity, and BMI on behavioral beliefs, normative beliefs, control beliefs, attitude toward the behavior, subjective norm, perceived behavioral control, intention, and behavior about milk/soft drink intake in school-age children. This chapter includes discussion of the study results, implications for practice, theory and policy, the limitations of the study, and recommendations for future research.
Discussion of Results
Description of eating behaviors and patterns of milk and soft drink intake
Breakfast. Despite the substantial decline in breakfast consumption among children since 1965, reported as between 64.7% and 74.9% depending on gender (Siega-
Riz, Popkin, & Carson, 1998), the majority of the respondents in this study (86%) had breakfast the morning they completed the questionnaire. This finding is consistent with
Berg et al.’s (2000) study where 96% of Swedish children were reported to eat breakfast
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at home and Bellisle and Rolland-Cachera’s (2007) study, in which 97% of the 9 to 11-
year-old French children had breakfast. The 14% proportion of the participants in our
study who skipped breakfast is consistent with the 10% proportion that was reported
recently (Nicklas & Hayes, 2008). These findings could point towards a slowdown or a
reversal of the previously reported decline in breakfast consumption.
Of the children who consumed breakfast, 72% had breakfast at home and 13% at
school. These figures are different from the ones found in another study in which, 49% of
children from nationally representative samples obtained from the Nationwide Food
Consumption Surveys of 1965, 1977–1978 and 1989–1991 ate breakfast at home, and
51% ate breakfast at school (Siega-Riz et al., 1998). This last study reports on behaviors
that took place 17 years ago which may have shifted significantly since. Although both
studies utilized the same recall method to collect eating behavior data, another possible
reason for the discrepancy in these figures may reside in the fact that our study relied on
mailed surveys and, despite being asked about ‘breakfast before school today,” the
participants may have filled them on a weekend when breakfast is consumed at home,
hence increasing the number of ‘at home’ responses.
Lunch. Almost all (99%) respondents had lunch the day prior to responding, and
the majority (73%) had it at school, followed by 22% at home. A study conducted in the
U.S. to analyze children's meal patterns over 2 decades similarly found that only 2% of
children skipped lunch (Nicklas, Morales et al., 2004). Moreover, in Bellisle and
Rolland-Cachera’s (2007) study, almost all French children (96% in 1997 and 97% in
1995) had lunch; however, two-thirds consumed it at home and one-third at the school. It is unclear if this discrepancy could be attributed to cultural differences. From 1973-1974
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to 1993-1994, the percentage of American children eating a school lunch declined from
89.7% to 78.2% and those eating lunch brought from home increased from 5.9% to
11.1% (Nicklas, Morales et al., 2004). Half of the respondents (53%) in our study got their lunch from home and 28% got it at school, possibly confirming both trends.
Dinner. The majority (93%) of respondents had dinner, of which 90% had it at home. The majority (83%) had dinner with family, 11% with others, and only 6% ate alone. Similarly, almost all French children (99%) had dinner, most often at home and in the company of all family members (73-87%) (Bellisle & Rolland-Cachera, 2007). Our findings are contrary to other findings indicating an increase in meals and snacks eaten away from home (Nicklas, Morales et al., 2004). From the 1970s to the 1990s, consumption of dinner at home has been been reported to decrease from 89.2% to 75.9
(Nicklas, Morales et al., 2004). Further studies are needed to determine whether our findings represent a reversal of this trend.
Milk intake. In our study, almost all children (91%) had ≥ 1 glass of milk on a
usual day during the school week. This result is consistent with the findings of Berg et
al.’s (2000) study, in which 93% of the Swedish children and adolescents drank milk
some time during the week. However, only 42% of the Swedish children drank milk at
breakfast, while nearly two-thirds of the respondents (64%) in our study reported
drinking milk during breakfast. This discrepancy could be attributed to the fact that Berg
et al.’s (2000) findings were drawn from 7- day food records, while our study used a 24-
hour dietary recall. Moreover, Berg et al. assessed milk intake for breakfast ‘everyday’
which could have resulted in exclusion of children who drank milk at breakfast on some,
but not all days of the week. Another possible explanation may be that the sample in Berg
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et al.’s study consisted of adolescents (11 to 15 years) and ours included younger children
(10 to 12 years). Based on prior research looking into trends of eating behavior in the
U.S., milk consumption has been found to decrease with increasing age (Demory-Luce et al., 2004; Friedman et al., 2007), suggesting that higher milk consumption in the present study may be associated with age.
Forty percent reported drinking milk with snacks. From 1977 to 1996, snacking among children ages 6 to 11 years has increased considerably from 76% to 91% (Jahns,
Siega-Riz, & Popkin, 2001). However, the mean consumption of milk reported as snacks has significantly decreased (Nicklas, Demory-Luce et al., 2004). In Canadian children 4 years and older, only 15.8% of snack calories were from milk products (Roblin, 2007).
The afternoon snack, a traditional meal for French children, was consumed by 86-88% of
the 1000 children sampled by Bellisle and Rolland-Cachera (2007). In 1993, 1995, and
1997 milk was consumed in 21%, 18%, and 16% of afternoon snacks, respectively.
However, we could not find data from other studies about proportion of children drinking
milk with snacks. This data may suggest that as snacking is on an increasing trend,
promoting milk intake during snacks may prove to be a successful strategy to improve on
calcium intake and weight parameters.
Soft drink intake. Overall, two-thirds of our sample (71%) consumed soft drinks.
Our findings are consistent with findings from other studies in which around 65% of
school-age children drank soft drinks (Friedman et al., 2007; Harnack et al., 1999).
However, in one study, only 30% of 8 to 13-year-olds reported drinking soft drinks
(Grimm et al., 2004) while others found higher proportions of female and male
adolescents (96%) drinking soda (Kassem & Lee, 2004; Kassem et al., 2003). The lower
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proportion of soda consumers in Grimm et al.’s (2004) study and the higher proportions
in Kassem and Lee’s (2004) and Kassem et al.’s (2003) studies may be explained by the
fact that the former studied both school-age children and adolescents (8 to 13 years) whereas the latter studied adolescents 13 to 18 years of age. All three studies had age groups different than ours and it was repeatedly shown that soft drink consumption varies dramatically by age, increasing beginning around 8 years (Friedman et al., 2007; Grimm et al., 2004; Rampersaud et al., 2003).
When asked “On a usual day during the school week, how much soda pop do you
drink,” 41% reported none, 27% one can, 23% two to three cans, and 6% more than 3
cans. Our findings are similar to those of Storey et al.’s (2004), in which 28.9%
consumed no soda, 30% consumed ≤ 1 serving, 25.4% consumed 1 to 2 servings, and
15.6% consumed > 2 servings. Again, as discussed previously, with older age groups,
more females (50%) and males (60%) drank ≥ 2 glasses of soda per day (Kassem & Lee,
2004; Kassem et al., 2003).
Only 19% of our respondents claimed drinking soda with snacks. When asked
what the respondents would choose to drink, the majority (45%) chose water, followed
by milk (26%) and soda (10%). Nearly half of the respondents choosing the “Other”
category preferred orange juice and lemonade. These findings are again consistent with
findings from the sample of French children, whose drinks during their snack were
reported being mostly water, juices and sodas (Bellisle & Rolland-Cachera, 2007). The difference lies in the preference of milk in our study when given the choice, whereas milk was not mentioned in the French study. Again, this finding points to a potential means to increase milk consumption through promoting it with snacks.
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It is interesting to note that while only 10% of respondents stated they would
choose to drink soda, nearly double consume it with snacks. This may be attributed to
social desirability, where, despite not being in contact with the researchers, they may
have wanted to impress us by choosing less soda as it may be perceived as an inferior
choice to milk. Alternatively, soda may be more available to children during snack time.
On the contrary, although almost all claimed to drink ≥ 1 glass of milk daily, only 26%
reported to drink it if they were given the choice. This may imply that there are factors
beyond the children’s control leading them to consume milk and, if given the choice, not
all of them would choose to drink it. Further research will be needed to explore the
reasons behind these discrepancies.
Analysis of research questions
Prediction of milk/soda drinking behaviors.
1. Does intention about milk/soft drink intake and perceived behavioral control
influence behavior about milk/soft drink intake in school-age children?
In explaining milk and soft drink intake behaviors among school-age children, only intention predicted milk and soda intake behavior, with stronger intention to drink milk/soft drink being more related to actual intake. Our findings about the contribution of intention compare favorably with other studies about milk and soft drink consumption in adolescents (Berg et al., 2000; de Bruijn et al., 2007 ; Gummeson et al., 1997; Kassem &
Lee, 2004; Kassem et al., 2003).
In this study the presence of a direct relationship between perceived behavioral
control and both milk and soda drinking behaviors was tested. The rationale for this
modification was that some children have no control over their milk and soft drink
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choices and thus the relationship between perceived behavioral control and the behaviors
through intention may not hold true. Contrary to Ajzen’s (1991) suggestion, perceived
behavioral control was not significantly correlated with either behavior nor was it an
independent predictor of them. These findings are congruent with other studies about
milk and soda drinking behaviors (Gummeson et al., 1997; Kassem & Lee, 2004; Kassem et al., 2003), the exception being Berg et al.’s (2000) study, in which perceived behavioral control added significantly to the prediction of milk choice by intention. The lack of an independent contribution of perceived behavioral control to the prediction of both behaviors in this study may be possibly due to children’s inaccurate perception of their degree of control over their milk/soda drinking behavior. Alternatively, this age group may lack actual control over their food choices through either parental decisions over availability of milk and soda or through school-based meal programs where milk or water may be the only options. Again, further research is needed to determine the etiologies behind this finding.
The predictiveness of the TPB has been found to be low (R2 < 0.3) with adults and adolescents and even lower for children (Baranowski et al., 1999). The R2 values have
been higher when the models were used to predict specific categories of foods,
suggesting that influences vary by food types. Despite having chosen specific food
categories, the predictive values of intention and perceived behavioral control were
relatively low for milk intake (4%) and for soda intake (14%). However, our results are
comparable with findings from other milk and soda prediction studies (Gummeson et al.,
1997; Kassem & Lee, 2004; Kassem et al., 2003). Similar to the other studies, the
relatively low predictive power of intention for milk and soda drinking behaviors may
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have been because the behaviors being predicted were current intake of milk and soft
drink, whereas the intention measured was intention to drink milk/soft drink in the future.
Despite the low predictive power of intentions for both behaviors, these findings point
out the importance of intention as a worthwhile target for future investigations to
ascertain its significance.
Prediction of intention.
2. Does attitude toward the behavior, subjective norm, and perceived behavioral
control influence intention about milk/soft drink intake in school-age children?
The three independent variables yielded a good level of prediction and together explained 49% of the variance in intention to drink milk and 44% of the variance in intention to drink soft drink supporting the use of the TPB with children. Attitude was a significant independent predictor of intention to drink both milk and soda and explained most of the variance in both behavioral intentions. This predictive pattern of attitudes is congruent with the other studies using the TPB in which attitudes have been the strongest predictors of intentions (Berg et al., 2000; de Bruijn et al., 2007; Gummeson et al., 1997;
Kassem & Lee, 2004; Kassem et al., 2003).
Despite the influences by parents and friends found on children’s and adolescent’s
milk and soda drinking behaviors, subjective norms surprisingly did not contribute to the
prediction of both behaviors in our study. There have been mixed findings about
subjective norm in the other TPB studies (Berg et al., 2000; de Bruijn et al., 2007;
Gummeson et al., 1997; Kassem & Lee, 2004; Kassem et al., 2003). A possible reason
for the weak or lack of contribution of subjective norm may be because it is usually operationalized as an injunctive norm i.e. social approval by significant others, responses
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to which have resulted in low variability due to high social desirability. As a possible
solution, Ajzen (2002) recommended the inclusion of items tapping descriptive norms i.e. whether important others themselves perform the particular behavior or not. Despite not being commonly used with children, Berg et al.’s (2000) incorporation of the concept of
descriptive norm as a subset of subjective norm improved the predictive power of the
other constructs on intents to consume the different alternatives of milk.
Interestingly, perceived control was able to predict intention to drink soda in our
study, but not intention to drink milk; however, it ranked second after attitude in the
strength of the prediction. This supports findings from all previously mentioned studies
about milk and soda consumption. Our findings are possibly not related to weak
measurement of this concept because perceived behavioral control was measured with
identical items for the milk and soda intake behaviors. A possible explanation may be
that school-age children have different perception of control over drinking milk versus
drinking soda or these behaviors may even be habitual.
These results point to the importance of attitudes in determining intentions and the
relatively minor influence of perceived behavioral control and subjective norm with this
population. Future research should: focus on promoting positive attitudes towards healthy
foods, investigate both injunctive and descriptive norms concurrently, and investigate the
extent to which the lack of influence in one behavior and not another is attributable to
measurement issues versus actual differences in perception of control with varying
behaviors or due to preformed habits.
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Prediction of attitude, Subjective norm, and perceived behavioral control
The strength of predictions of attitude, subjective norm, and perceived behavioral control from their underlying beliefs varied considerably. The behavioral beliefs accounted for a considerable amount of variance in milk intake and soft drink intake
(45% and 52%, respectively). The amount of explained variance by normative beliefs was even more for subjective norms to milk intake (60%). However, the strength of the predictions weakened considerably for subjective norms to soft drink intake, perceived behavioral control to drink milk and soft drink (30%, 14%, and 8%, respectively). Few studies have investigated the underlying belief components; however, the variations in the strength of the predictions are consistent with the soft drink consumption studies conducted with males and females (Kassem & Lee, 2004; Kassem et al., 2003). A possible explanation for the weak predictions is that, contrary to Ajzen’s recommendation of eliciting the salient beliefs from participants using a qualitative method, we included the most commonly elicited ones from previous TPB studies. In addition, in order to minimize subject burden with children, we used only the beliefs that were found to have a significant influence. Not all the included beliefs may have matched our participants’ individual beliefs. For example, instead of the control beliefs that we chose: availability at home and at school, and being offered by parents, some others such as quenching thirst, seeing advertisements, and having enough money to buy soda may have matched the children’s beliefs thus yielding higher predictions.
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3. Do behavioral beliefs about milk/soft drinks influence attitude toward milk/soft
drink intake in school-age children?
Taste of milk and soda were one of the stronger predictors of attitude toward milk/soda intake. Taste was an important influence on the participants’ choice of milk/soda. The importance of taste has been repeatedly found to be the strongest or one of the strongest influences on children’s and adolescents choice of milk and soda (Berg et al., 2000; de Bruijn et al., 2007; Gummeson et al., 1997; Kassem & Lee, 2004; Kassem et al., 2003). Future interventions promoting healthy eating behavior should incorporate the importance of taste to entice children to choose milk as the tastier beverage.
Being healthy ranked second in predicting attitude toward milk and soda intake.
The participants thought that drinking milk/soda makes them healthy. This finding supports findings from previous milk and soda studies (Berg et al., 2000; Kassem & Lee,
2004; Kassem et al., 2003). It is interesting to find that children think drinking both milk and soda makes them healthy. This may explain the increasing consumption of soft drinks over the past couple of decades. These findings point to the importance of further investigating the reasons that lead children to think soda consumption makes them healthy and emphasizing programs that underscore the unhealthy consequences of soda consumption.
The third belief that drinking milk/soda makes one gain weight had no independent
influence in predicting attitude toward milk/soda intake. Weight gain was an influential
factor for attitude toward soft drink intake only among females (Kassem et al., 2003) and
for attitude toward milk intake in Swedish adolescents (Berg et al., 2000). These findings run against the misconception about milk being fattening, which may lead
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children, especially females, to limit their milk intake (Neumark-Sztainer et al., 1999).
However, it is alarming to find that children have a misconception about soft drink not
making them gain weight and thus not influencing their soda intake. Milk and soda intake
and their relation to weight gain should be addressed in health promotion programs. In
addition, a better understanding of “diet” soft drinks needs to be included as it is not clear
that children of this age always understand which sodas are low in calories and which are
not.
4. Do normative beliefs about milk/soft drinks influence subjective norm about
milk/soft drink intake in school-age children?
Only friends were an independent significant predictor of subjective norm to milk
and soft drink intake, with participants wishing to comply more with what friends think
they should be drinking than what someone in the family thinks. In other studies, friends
have been found to influence adolescents’ milk and soda intake; however these influences
have mostly been weaker than those of parents (Berg et al., 2000; de Bruijn et al., 2007;
Gummeson et al., 1997; Kassem & Lee, 2004; Kassem et al., 2003). Contrary to our
findings, Gummeson et al. (1997) have found friends to be unimportant in children’s and
adolescents’ milk choice, which may be because their sample included both children and
adolescents whose perception of referents as influences on their food choices may vary.
A possible reason for the lack of consistency between our findings and the others is that
we have asked about ‘someone in my family’ as a referent, while the other studies
mention parents or mother and father. Future studies about children’s food choices should further investigate the influence of parents, as parents role in influencing their children’s
food choices has been well documented (Birch & Fisher, 1998; Koivisto Hursti, 1999).
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This is important in order to involve proper referents in promoting children’s healthy food choices. As well, our wording choice was deliberate to capture the diversity of living arrangements where grandparents and other family members may be more influential than parents.
5. Do control beliefs about milk/soft drinks influence perceived behavioral control
about milk/soft drink intake in school-age children?
Availability of milk in home refrigerator was the only predictor of perceived behavioral control to drink milk. The participants thought that having milk available in their home refrigerator made it easier for them to drink it. This finding supports a number of other studies about milk and soda intake (Berg et al., 2000; de Bruijn et al., 2007;
Gummeson et al., 1997; Kassem & Lee, 2004; Kassem et al., 2003). The other two beliefs about availability at school and whether being offered milk by parents made it easier for them to drink milk did not predict perceived behavioral control to drink milk.
This underscores the importance of making milk available at home in order to promote its consumption.
It is interesting to note that, despite having significant positive associations with perceived behavioral control to drink soda, none of the control beliefs about availability of soda in home refrigerator, availability at school, and being offered by parents predicted perceived behavioral control to drink soda. Since the control beliefs are not multicollinear, this discrepancy may be because the strength of the prediction of perceived behavioral control to drink soda (8%) is weak. The lack of influence of availability of soda at school may also be explained by the fact that most elementary schools in Cleveland no longer make soft drinks available on their premises.
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Gender, ethnicity, and BMI differences
6. Are there differences by gender on behavioral beliefs, normative beliefs, control
beliefs, attitude, subjective norms, perceived behavioral control, intention and
behavior about milk/soft drink intake in school-age children?
No significant differences were found between males and females in terms of the milk and the soda pop TPB variables and both behaviors. Only Berg et al. (2000) have investigated gender differences in the TPB constructs and milk intake. Our findings concerning the lack of gender differences in the TPB variables and milk consumption are consistent with Berg et al.’s findings. Gender differences were only found in intentions and attitudes with males being more in favor of higher fat milk than females. No significant gender differences were found for the TPB constructs on intention and consumption and, compared to boys, girls evaluated weight gain more negatively (Berg et al., 2000). Soft drink consumption has been found to be higher among males than females
(Friedman et al., 2007; Grimm et al., 2004). Our findings indicate the need for further investigation of gender differences within school-age children. Findings from such studies are essential in developing tailored interventions based on gender differences.
7. Are there differences by ethnicity on behavioral beliefs, normative beliefs, control
beliefs, attitude toward the behavior, subjective norm, perceived behavioral
control, intention and behavior about milk/soft drink intake in school-age
children?
Compared to the minority group, white participants were found to have stronger
intention to drink milk, had stronger perception that drinking milk makes them healthy,
had stronger perception that someone in their family thinks they should drink 3 cups of
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milk every day, and that having milk in home refrigerator would make it easier for them
to drink 3 cups every day. Contrary to the racial differences found in the milk data,
compared to the white participants, the minority group had stronger perception that
someone in their family and their friends think they should drink soda pop every day and
they drank significantly more soft drinks.
To our knowledge, no studies have investigated the effect of ethnicity on the
influences on children’s milk and soft drink intake. The available data focuses on its
effect on actual consumption of milk and soda. Our findings are supported by previous
studies that have shown significant racial differences in these behaviors. Asian ethnicity
has been described to be negatively associated with milk and calcium intake (Novotny et al., 2003; Oshiro, Novotny, & Titchenal, 2003). Similarly, African American males aged
9 to 18 years and females 4 to 18 years have also been found to consume significantly less milk than their non-African American counterparts (Fulgoni et al., 2007). Black non-
Hispanic and low-income children were reported to be more likely to consume soft drinks
at school if they were made available to them (Fernandes, 2008). These ethnic differences
in milk and soft drink consumption could be partially explained by the higher prevalence
of lactose intolerance among African Americans and Asian Americans (Nicklas, 2003).
Whether differences in socioeconomic status among different ethnicities confound our
observations needs to be ascertained in further studies.
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8. Are there differences by BMI on behavioral beliefs, normative beliefs, control
beliefs, attitude toward the behavior, subjective norm, perceived behavioral
control, intention and behavior about milk/soft drink intake in school-age
children?
Our findings indicated no significant differences between participants in the
‘healthy weight’ category and those in the ‘at risk of overweight’ category in terms of the milk and the soda pop TPB variables and both behaviors. Few studies have investigated associations of BMI and beverage consumption in children. For 10-year-old sweetened-
beverage consumers, mean BMI has been found to significantly increase over two decades (Rajeshwari, Yang, Nicklas, & Berenson, 2005). In a study evaluating diet quality and BMI by beverage patterns, the BMI of children aged 6 to 11 years was found to be significantly higher in the soda patterns compared to the high-fat milk patterns
(LaRowe, Moeller, & Adams, 2007). To our knowledge, our study is the first to investigate the influence of BMI differences on the TPB constructs in school-age children. Since prolonged exposure to soft drink is needed to impact BMI, the lack of association between BMI and TPB variables in both behaviors could be attributed to the fact that our study population consisted of younger children. Future research should follow school-age children longitudinally to determine if factors influencing milk and soda consumption may vary by the different BMI categories.
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Implications for practice, theory and policy
Implications for practice
The epidemic of childhood overweight and obesity is expected to progress into a significant public health burden as dietary patterns persist through adulthood, leading to chronic disease. Early interventions in children’s lives are needed to promote healthy eating behaviors that will be maintained through adulthood. To date, most interventions have been aimed at limiting availability, as illustrated by regulations banning soft drink sale on school premises. Our study offers a glimpse into understanding factors that determine school-age children’s soft drink and milk drinking behavior. It underscores the
lack of influence of availability on soda intake and the importance of taste in the choice
process. Moreover, it was alarming to find that children believe milk and soft drink intake
both contribute positively to their health and do not relate soda intake to weight gain.
Such an understanding will allow devising behavior-altering interventions that will have
the advantage of being independent of the traditional school versus home context. For
example, health education programs should focus more on explaining the health effects
of various drinks to school age children.
Implications for theory
To our knowledge, our study is the first to use the TPB to explain milk and soft
drink intake in school-age children in the U.S. It was also the first to introduce VASs into
the TPB concepts. The TPB was able to explain most of the influences on milk and soda
intake, pointing to its usefulness and applicability in this context. However, since some of
the variance in both behaviors could not be accounted for by the TPB, further
operationalization of the concepts will be needed.
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Implications for policy
Several policy interventions currently aim at restricting availability of soda to promote healthier drinking patterns. However, such interventions are effective only as long as the restrictions are in place and fall short when children are outside the restrictive environment. For example, “pouring rights” contracts have been the subject of many controversies and the focus of many health advocacy groups for their potential contribution to the epidemic of childhood overweight and obesity. A simple screening tool about nutritional habits for the child to fill may be designed for regular use in HMOs such as Kaiser Permanente, as well as in pediatric clinics. Such a tool would serve as a trigger for targeted interventions for clinicians in providing health promotion guidance.
As well, consideration needs to be given as to the age at which children complete a simple dietary recall as the study findings indicate that children are capable of completing a recall of their “normal day” intake.
Through better understanding children’s attitudes, social norms, behavioral controls, beliefs and intentions, our results provide a means to develop interventions that will shape behavior in a more permanent manner. A policy aimed at thoroughly explaining to children the effects of various drinking items on their health might prove beneficial. Nurses, through their presence in schools, can assume a leading role as educators and actively participate in state mandated health education programs tailored to children. As well, nurses, with a focus on health promotion, may be able to influence other groups where there is the potential to impact child health, such as YMCA/YWCA programs, through Boy and Girl Scouts and other youth organizations.
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Limitations of the Study
There were some limitations in this study with respect to research design and
measurement. First, this study utilized a cross-sectional design which does not allow determining directions and possible causality of associations. With the conflicting views on the beverage –milk displacement hypothesis, these trends in beverage and milk consumption need to be determined in longitudinal studies. In the absence of a randomized control design, longitudinal data provide the best means to establish that observed effects are causal and not due to confounding, selection bias, or reverse causality (Lee & Frongillo, 2001).
Second, we relied on self-reported data for the milk and soft drink intake which
may have been affected by memory issues and insufficient recall. Thus the behavioral
measures in this study may have been somewhat biased because of self-report. Third, we
did not address the possible effect of social desirability which may have affected the
responses. The effect of social desirability should have been minimized by the use of an
anonymous mailed survey and the fact that parents and participants were informed that
the researchers would not know what participants would report. However, since we are
not aware if the participants filled the questionnaires on their own or in the presence of
parents, we would suspect that some of them may have wanted to impress parents by
indicating more preference to milk as the healthier beverage. Fourth, 86% of our sample lived in a two parent family and all had health insurance, both of which is not
representative of 10 to 11-year-olds in Cleveland, Ohio or other American children in
general. Finally, all the measures were developed for the purpose of this study and
reliability and validity established with this sample. The Cronbach’s alpha for the
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Subjective Norm to Milk Intake and Soda Pop Intake Scales was .57 and .56,
respectively, and for the Perceived Behavioral Control over Milk Intake and Soda Pop
Intake Scales was .50 and .66, respectively. Further development/refinement of these
scales is needed to improve their reliability scores.
Recommendations for Future Research
Despite the limitations of this study, our findings are valuable in serving as preliminary steps for further research to allow nurses and health care workers to ultimately plan effective interventions to promote healthy beverage choices by school-age
children thus reducing risk factors for overweight. The following are recommendations
for further research:
1- Longitudinal studies to determine whether milk has simply become less popular
or whether soft drinks have been substituted for milk.
2- Study other food items to further validate the applicability of the TPB with
school-age children.
3- Investigate whether school-age children distinguish carbonated beverages from
sports drinks and flavored/vitamin water.
4- Study the impact of the media on the selection of milk or soft drink by school-age
children.
5- Design of a qualitative study to generate emerging beliefs specific to American
school-age children and replication of the study with a larger sample size to
generate more compelling evidence for associations between influences on
children’s milk and soft drink intake and their actual consumption.
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6- Planning effective interventions to promote healthy beverage choices by school-
age children to possibly reduce risk factors for overweight.
7- Replication of the study in Lebanon and design of a comparative study to explore
cultural differences in milk and soft drink intake among American and Lebanese
school-age children.
Summary
This study was conducted to investigate influences on school-age children’s milk
and soft drink intake behaviors. The results indicated that the majority of the children had
≥ 1 glass of milk on a usual day during the school week and two-thirds consumed soft
drinks. Within the TPB variables, intention predicted milk and soda intake, attitude had
the strongest contribution, followed by perceived behavioral control only in predicting
soda intention. Subjective norms did not contribute to the prediction. Within the beliefs,
taste and being healthy predicted attitudes, friends predicted subjective norms, and
availability of milk in home refrigerator predicted perceived behavioral control to drink
milk. When investigating differences in terms of the milk and the soda pop TPB variables
and both behaviors, none were found between males and females and between
participants in the ‘healthy weight’ and the ‘at risk of overweight’ categories. Compared
to the minority group, white participants were found to have stronger intention to drink
milk, perceived that drinking milk makes them healthy, had stronger perception that
someone in their family thinks they should drink 3 cups of milk every day and that
having milk in home refrigerator would make it easier for them to drink it. Compared to
the white participants, the minority group had stronger perception that someone in their family and their friends think they should drink soda pop every day and they drank
143 significantly more soft drink. These findings have many implications for practice, theory and policy; however, the study has some limitations with respect to cross-sectional design, self-report of behaviors, effect of social desirability, and measurement issues.
Ultimately, prospective studies assessing beverage patterns over time and replication of this study with larger samples and various foods are needed to validate the exact influences and intervene to possibly halt the rising proportion of overweight children.
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APPENDIX A
Date: ………………. ID: ……………..
Influences on School-age Children’s Milk and Soft Drink Intake
Tell me about yourself
Birth Date: ______
Place a (X) in the space beside your response. Respond to questions only above the black line.
1- I am a (1) Boy (2) Girl ______
2- I am: (1) American Indian or Alaskan Native ______(2) Asian ______(3) Black or African American (not of Hispanic Origin) ______
(4) Hispanic or Latino ______(5) Native Hawaiian or Other Pacific Islander ______(6) White or Caucasian (Not of Hispanic origin) ______
3- Who do you live with? (1) Mother only ______(5) Grandfather only ______(2) Father only ______(6) Grandmother & Grandfather ______(3) Mother & Father ______(7) Other ______(4) Grandmother only ______
For researchers’ use
Height (in inches): ______
Weight (in pounds): ______
BMI: ______
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APPENDIX B
Date: ………………. ID: ……………..
Influences on School-age Children’s Milk and Soft Drink Intake
24-Hour Dietary Recall
Place a (X) in the space beside your answer
1- Did you eat anything before school today? (1) Yes ____ (2) No ____ 2- Where did you eat this morning’s food? (1) Home ____ (2) School ____ (3) Car ____ (4) Another place ____ (5) I did not eat anything before school today ____ 3- Did you drink milk before school this morning? (1) Yes ____ (2) No ____ 4- On a usual day during the school week how much milk do you drink? (Write the number of glasses or cartons. Place a 0 if you don’t drink any milk). Glasses ______Cartons ______
5- Did you eat lunch yesterday? (1) Yes ____ (2) No ____ 6- Where did you eat lunch? (1) Home ____ (2) School ____ (3) Another place ____ (4) I did not eat lunch yesterday ____ 7- Where did you get your lunch from? (1) Bought it ____ (2) Home ____ (3) Friends ____ (4) School ____ (5) None ___ 8- Did you have a meal after school and before bedtime (1) Yes ____ (2) No ____ yesterday?
9- Where did you eat this meal before bedtime? (1) Home ____ (2) Another place ____ (3) I did not eat anything before bedtime _____
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10- Who prepares food for you at home? (1) My family ____ (2) Me ____ (3) My family and me____ (4) Other people ____
11- Had food last night (1) By myself ____ (2) With family ____ (3) With others _____ 12- Do you drink soda pop? (1) Yes ____ (2) No ____ 13- On a usual day during the school week how much soda pop do you drink? (Write the number of cans, cups or 16 oz bottles. Place a 0 if you don’t drink any soda pop).
______
14- On a typical school day what would you choose to drink (circle one)?
OTHER NOTHING (please write what) ______
15- On a usual day during the school week, while (1) Yes ____ (2) No ____ eating snacks do you drink milk?
16- On a usual day during the school week, while (1) Yes ____ (2) No ____ eating snacks do you drink soda pop?
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APPENDIX C
Date: ………………. ID: ……………..
Influences on School-age Children’s Milk and Soft Drink Intake
Milk Intake Questionnaire
Place a (×) in the space beside your response
Does drinking milk ever make you sick? ____ Yes ____ No
If you marked no, please go on to the next page.
If you marked yes, please go on to the next section marked Soda Pop Intake Questionnaire.
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Intention to Drink Milk Scale
Place a (×) in the square below your response
Definitely Maybe Don't Maybe yes Definitely
not not know yes
1. I plan to drink 3 cups of milk every day
Very Don’t Unlikely Likely Very likely unlikely know
2. How likely is it that you will drink 3 cups of milk every day
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Directions: Tom and his friend were playing in the snow. Tom’s mom came over and told them: ‘I will ask you a question and you will answer me by placing a (×) for your response on the line. The vertical line is the middle of the horizontal line.
CORRECT example How much do you like playing in the snow?
X Not at all Very much
Incorrect example How much do you like playing in the snow?
Not at all X Very much
Attitude Toward Milk Intake Scale
3-5. For me drinking 3 cups of milk every day is
Very unimportant Very important
Very bad Very good
Very unenjoyable Very enjoyable
6. How much do you like milk?
Not at all A lot
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Behavioral Beliefs about Milk Intake Scale
7. Drinking milk makes me healthy
Strongly disagree Strongly agree
8. Milk tastes
Very bad Very good
9. Drinking milk makes me gain weight
Strongly disagree Strongly agree
10. For me being healthy is
Very unimportant Very important
11. For me taste of milk is
Very unimportant Very important
12. For me gaining weight is
Very bad Very good
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Subjective Norm to Milk Intake Scale
13. My friends think that I should drink 3 cups of milk every day
Strongly disagree Strongly agree
14. My friends drink 3 cups of milk every day
Strongly disagree Strongly agree
Normative Beliefs about Milk Intake Scale
15. Someone in my family thinks I should drink 3 cups of milk every day
Strongly disagree Strongly agree
16. When it comes to drinking milk, I want to do as this person in my family thinks I should
Not at all Very much
17. When it comes to drinking milk, I want to do as my friends think I should
Not at all Very much
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Perceived Behavioral Control over Milk Intake Scale
18. For me drinking 3 cups of milk every day would be
Very difficult Very easy
19. I can decide whether or not I drink 3 cups of milk every day
Strongly disagree Strongly agree
20. How much control do you think you have over drinking 3 cups of milk every day?
No control Complete control
21. Do you always get to choose what you drink at home?
Definitely no Definitely yes
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Control Beliefs about Milk Intake Scale
22. Is there milk in your home refrigerator?
Never Always
23. Having milk in our home refrigerator would make it easier for me to drink 3 cups every day
Strongly disagree Strongly agree
24. My parents offer me milk with meals and snacks
Strongly disagree Strongly agree
25. Being offered milk by my parents would make it easier for me to drink 3 cups every day
Strongly disagree Strongly agree
26. Do you drink milk at school?
Never Always
27. Having milk available at school would make it easier for me to drink 3 cups every day
Strongly disagree Strongly agree
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APPENDIX D
Date: ………………. ID: ……………..
Influences on School-age Children’s Milk and Soft Drink Intake
Soda Pop Intake Questionnaire
Place a (×) in the space beside your response
Are you allowed to drink soft drinks and pop? ____ Yes ____ No
If you mark no here, you can stop and hand this in.
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Intention to Drink Soda Pop Scale
Place a (×) in the square below your response
Definitely Maybe Don't Maybe yes Definitely
not not know yes
1. I plan to drink soda pop every day
Very Don’t Unlikely Likely Very likely unlikely know
2. How likely is it that you will drink soda pop every day
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Attitude Toward Soda Pop Intake Scale
Directions: Place a (×) for your response on the line
3-5. For me drinking soda pop every day is
Very unimportant Very important
Very bad Very good
Very unenjoyable Very enjoyable
6. How much do you like soda pop?
Not at all A lot
Behavioral Beliefs about Soda Pop Intake Scale
7. Drinking soda pop makes me healthy
Strongly disagree Strongly agree
8. Soda pop tastes
Very bad Very good
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9. Drinking soda pop makes me gain weight
Strongly disagree Strongly agree
10. For me taste of soda pop is
Very unimportant Very important
Subjective Norm to Soda Pop Intake Scale
11. My friends think that I should drink soda pop every day
Strongly disagree Strongly agree
12. My friends drink soda pop every day
Strongly disagree Strongly agree
Normative Beliefs about Soda Pop Intake Scale
13. Someone in my family thinks I should drink soda pop every day
Strongly disagree Strongly agree
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14. When it comes to drinking soda pop, I want to do as this person in my family thinks I should
Not at all Very much
15. When it comes to drinking milk, I want to do as my friends think I should
Not at all Very much
Perceived Behavioral Control over Soda Pop Intake Scale
16. For me drinking soda pop every day would be
Very difficult Very easy
17. I can decide whether or not I drink soda pop every day
Strongly disagree Strongly agree
18. How much control do you think you have over drinking soda pop every day?
No control Complete control
19. Do you always get to choose what to drink at home?
Definitely no Definitely yes
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Control Beliefs about Soda Pop Intake Scale
20. Is there soda pop in your home refrigerator?
Never Always
21. Having soda pop in our home refrigerator would make it easier for me to drink it every day
Strongly disagree Strongly agree
22. My parents offer me soda pop with meals and snacks
Definitely no Definitely yes
23. Being offered milk by my parents would make it easier for me to drink
Strongly disagree Strongly agree
24. Do you drink soda pop at school?
Never Always
25. Having soda pop available at school would make it easier for me to drink it every day
Strongly disagree Strongly agree
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Thank you for your participation. Please review to make sure you have completed all questions.
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BIBLIOGRAPHY
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