Freshman 15: Fact Or Fiction?
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Descriptive Epidemiology Freshman 15: Fact or Fiction? Michelle L. Morrow,* Kristiann C. Heesch,*† Mary K. Dinger,* Holly R. Hull,* Allen W. Kneehans,‡ and David A. Fields§¶ Abstract results do not support the purported “freshman 15” weight MORROW, MICHELLE L., KRISTIANN C. HEESCH, gain publicized in the popular media. MARY K. DINGER, HOLLY R. HULL, ALLEN W. KNEEHANS, AND DAVID A. FIELDS. Freshman 15: fact Key words: college students, weight gain, women, body or fiction? Obesity. 2006;14:1438–1443. composition Objective: The objective of this study was to investigate changes in body weight, BMI, body composition, and fat Introduction distribution among freshman women during their 1st year of The incidence of obesity among adults in the United college. States increased by ϳ50% per decade throughout the 1980s Research Methods and Procedures: Freshman women dur- and 1990s, with the trend expected to continue (1). Partic- ing the 2004 to 2005 academic year were recruited to ularly worrisome are data from the Behavioral Risk Factor participate. The initial baseline visit occurred within the first Surveillance System that show the greatest increase in over- 6 weeks of the fall 2004 semester, with the follow-up visit weight and obesity from 1991 to 1998 in the United States occurring during the last 6 weeks of the spring 2005 semes- occurring in the 18- to 29-year-old age group (from 7.1% to ter. At each visit, height, weight, BMI, waist and hip cir- 12.1%), with those having “some college education” exhib- cumferences, and body composition (by DXA) were ob- iting even greater increases (from 10.6% to 17.8%) (2). This tained. trend portends badly for the future health of America and, in Results: One hundred thirty-seven participants completed fact, has led some to predict a potential decline in life Ͻ both the fall and spring visits. Significant (p 0.0001) expectancy in the United States in the 21st century (3–5). increases between the fall and spring visits were observed Entering college at 18 to 19 years of age has been for body weight (58.6 vs. 59.6 kg), BMI (21.9 vs. 22.3), recognized as a “critical” period that dictates whether indi- percentage body fat (28.9 vs. 29.7), total fat mass (16.9 vs. viduals will live healthy lifestyles in their subsequent adult 17.7 kg), fat-free mass (38.1 vs. 38.4 kg), waist circumfer- years (6). Results from the National College Health Risk ence (69.4 vs. 70.3 cm), and hip circumference (97.4 vs. Behavior Survey indicate that college students are develop- 98.6 cm), with no significant difference observed in the ing poor nutritional and physical activity habits, which may waist-to-hip ratio (0.71 vs. 0.71; p ϭ 0.78). lead to future health burdens later in life (7). In 2003, Huang Discussion: Although statistically significant, changes in et al. (7–9) reported that 22% of college students in his body weight, body composition, and fat mass were modest sample were overweight or obese, whereas others suggest for women during their freshman year of college. These rates as high as ϳ30%. Therefore, if this critical period of transition from high school to college is ignored, it is possible that these health habits will be carried through the Received for review December 2, 2005. college years into adulthood, with inevitable weight gain Accepted in final form May 30, 2006. The costs of publication of this article were defrayed, in part, by the payment of page and a whole constellation of obesity-related disorders, such charges. This article must, therefore, be hereby marked “advertisement” in accordance with as stroke, heart disease, diabetes, and cancer, occurring later 18 U.S.C. Section 1734 solely to indicate this fact. *Department of Health and Exercise Science, University of Oklahoma, Norman, Oklahoma; in life. †School of Human Movement Studies, University of Queensland, Brisbane, Queensland, A common belief among the lay public is that body Australia.; ‡Department of Nutritional Sciences, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma; and §Department of Pediatrics and ¶Children’s Medical weight increases after entry into college, and the phrase Research Institute’s Metabolic Research Center, University of Oklahoma Health Science “freshman 15” has been coined to describe the 15 pounds Center, Oklahoma City, Oklahoma. that students presumably gain over their freshmen year. Address correspondence to David Fields, Department of Pediatrics and Children’s Medical Research Institute’s Metabolic Research Center, University of Oklahoma Health Science However, little scientific evidence exists to substantiate or Center, OUCP Diabetes and Endocrinology, 940 NE Thirteenth Street, CH 2B2426, Okla- rebut this commonly held belief (10,11). The few studies homa City, OK 73104. E-mail: [email protected] that have examined weight gain among freshmen college Copyright © 2006 NAASO students are equivocal. Some showed a significant weight 1438 OBESITY Vol. 14 No. 8 August 2006 Freshman 15, Morrow et al. gain (10,12,13), whereas others reported no significant Weight and height were measured with a balance beam weight increase (14,15). The inconsistent findings may be scale and stadiometer (Detecto Manual Physician, Webb due, in part, to studies using different follow-up periods City, MO), respectively, and used to compute BMI (kilo- (i.e., only a portion of the freshman year, a portion of the grams per meter squared). For measurement of both height freshman and sophomore years, or, in a few studies, the and weight, participants were instructed to remove their entire freshman year), the use of small sample sizes (n ϭ 40 shoes and all heavy clothing (e.g., sweaters, jackets, belts). to 60), and the inclusion of both men and women. Addi- A plastic flexible Gulick tape measure was used to assess tionally, no study that we are aware of has studied changes waist and hip circumferences. The waist measurement was in body composition using DXA. Other studies have relied taken at one-half the distance between the bottom of the on body weight as the sole outcome measure, which does xiphoid process and the umbilicus, and the hip measurement not allow for detecting changes in fat and fat-free mass was taken at the largest anterior protrusion. The ratio be- (10,11,15,16). Given the limitations of past studies investi- tween waist and hip was computed as a measure of fat gating weight gain in college students, this study was im- distribution. plemented to track body weight and body composition DXA model Lunar DPX-IQ (Lunar Corporation, Madi- changes in a cohort of women over the fall and spring son, WI) was used to assess body composition, specifically semesters of their freshman year of college. percentage body fat, total fat mass, and total fat-free mass. To prevent discrepant readings among multiple assessors, scans were performed and analyzed by one technician using Research Methods and Procedures software version 4.7b. Calibration of the DXA occurred at the beginning of each day of testing. For the scan, subjects Participants were placed on the DXA scanning table; straps were placed After approval by the Institutional Review Board, fresh- around the ankles to keep them in the correct position. men women attending a large Midwest university (Univer- Anterior posterior thickness was measured at the midsection sity of Oklahoma, Norman, OK, with an enrollment of to determine the appropriate scan speed. The visit lasted ϳ25,000 students) were recruited by mass e-mail, flyers ϳ30 minutes. The day-to-day coefficient of variation for the posted around the campus, and announcements in college estimation of percentage fat mass in our laboratory is 1%. courses popular with freshmen women. Inclusion criteria were the following: female, enrolled as a full-time freshman at the university during the fall 2004 semester and planning Protocol to be enrolled during the spring 2005 semester, and 18 to 21 Potential participants were screened by telephone and years old at the time of the initial fall visit. Exclusion e-mail. Each eligible participant was then scheduled to visit criteria were the following: pregnant or planning to become the Body Composition Laboratory within the first 6 weeks pregnant during the study period, participation in any of the of the fall 2004 semester. Participants were instructed to university’s intercollegiate athletic teams, participation in arrive for their visit having fasted for at least 6 hours, with any organized sports team, having a metabolic disease that no exercise occurring within 24 hours. At the visit, partic- affects body weight and body distribution (e.g., Cushing’s ipants were re-screened to confirm eligibility. Each eligible Syndrome), and taking medication or drugs known to im- participant completed informed consent and Health Insur- pact body weight and distribution (e.g., steroids, growth ance Portability & Accountability Act of 1996 forms, com- hormone, ephedrine, and nicotine). pleted the demographic and physical activity question- naires, had height and weight assessed, and had hip and waist circumferences measured. Subjects were then scanned Study Design with the DXA. The study used a one-group, longitudinal research design. Participants were contacted by telephone and e-mail dur- The outcome measures were the participants’ body weight, ing the first half of the spring semester to schedule the BMI, body composition, and fat distribution. Data were follow-up visit within the last 6 weeks of the semester. The collected during the first 6 weeks of the fall 2004 semester follow-up visit included the same procedures used during and the last 6 weeks of the spring 2005 semester. the baseline visit for measurement of all anthropometric and body composition variables. The average number of weeks Measures between visits was ϳ29 weeks, with a range of 24 to 33 For descriptive purposes, demographic characteristics weeks.