Neighbourhood-Socioeconomic Variation in Women's Diet: the Role Of
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European Journal of Clinical Nutrition (2010) 64, 1423–1432 & 2010 Macmillan Publishers Limited All rights reserved 0954-3007/10 www.nature.com/ejcn ORIGINAL ARTICLE Neighbourhood-socioeconomic variation in women’s diet: the role of nutrition environments LE Thornton, DA Crawford and K Ball Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia Background/Objectives: Living in socioeconomically disadvantaged neighbourhoods is associated with increased risk of a poor diet; however, the mechanisms underlying associations are not well understood. This study investigated whether selected healthy and unhealthy dietary behaviours are patterned by neighbourhood-socioeconomic disadvantage, and if so, whether features of the neighbourhood–nutrition environment explain these associations. Subjects/Methods: A survey was completed by 1399 women from 45 neighbourhoods of varying levels of socioeconomic disadvantage in Melbourne, Australia. Survey data on fruit, vegetable and fast-food consumption were linked with data on food store locations (supermarket, greengrocer and fast-food store density and proximity) and within-store factors (in-store data on price and availability for supermarkets and greengrocers) obtained through objective audits. Multilevel regression analyses were used to examine associations of neighbourhood disadvantage with fruit, vegetable and fast-food consumption, and to test whether nutrition environment factors mediated these associations. Results: After controlling for individual-level demographic and socioeconomic factors, neighbourhood disadvantage was associated with less vegetable consumption and more fast-food consumption, but not with fruit consumption. Some nutrition environmental factors were associated with both neighbourhood disadvantage and with diet. Nutrition environmental features did not mediate neighbourhood-disadvantage variations in vegetable or fast-food consumption. Conclusions: Although we found poorer diets among women living in disadvantaged neighbourhoods in Melbourne, the differences were not attributable to less supportive nutrition environments in these neighbourhoods. European Journal of Clinical Nutrition (2010) 64, 1423–1432; doi:10.1038/ejcn.2010.174; published online 1 September 2010 Keywords: socioeconomic status; neighbourhood; food intake; fast foods; fruits; vegetables Introduction attention has shifted to socioeconomic differences at the neighbourhood level. Evidence of associations with neigh- Within developed countries, few individuals meet dietary bourhood disadvantage are mixed, with some studies recommendations for fruits and vegetables (Magarey et al., showing inverse associations between neighbourhood dis- 2006; Tamers et al., 2009), whereas consumption of energy- advantage and dietary quality (Turrell et al., 2009), whereas dense foods is increasing (Guthrie et al., 2002). These dietary others report no difference after controlling for individual behaviours increase the risk of obesity (Pereira et al., 2005; characteristics (Giskes et al., 2006). Buijsse et al., 2009), coronary heart disease (Ness and Powles, Where neighbourhood-level differences exist, it has been 1997) and diabetes (Pereira et al., 2005). suggested that these may operate through variations in Determinants of dietary behaviours have traditionally community and/or consumer nutrition environments been linked to individual characteristics such as socio- (Glanz et al., 2005). The ‘community nutrition environment’ economic position (SEP), with lower SEP associated with less relates to the type and location of food stores in an area, healthy diets (Ball et al., 2006; Roos et al., 2008). Recently, whereas ‘consumer nutrition environment’ relates to within- store factors such as product availability, quality, price and Correspondence: Dr LE Thornton, Centre for Physical Activity and Nutrition opening hours. For community nutrition environments, Research, School of Exercise and Nutrition Sciences, Deakin University, studies have shown patterning between neighbourhood 221 Burwood Highway, Burwood, Victoria, 3125, Australia. disadvantage and access to fast-food restaurants (Cummins E-mail: [email protected] Received 8 April 2010; revised 5 July 2010; accepted 14 July 2010; published et al., 2005; Pearce et al., 2007); however, no trend is online 1 September 2010 decipherable for supermarkets (Pearce et al., 2008; Neighbourhood-socioeconomic variations in diet LE Thornton et al 1424 Ball et al., 2009). Although some studies report that these In 2004, 2400 women aged 18–65 years from these differences are unrelated to diet (Ball et al., 2006; Turrell and 45 suburbs were posted a survey assessing dietary behaviours Giskes, 2008), others have shown greater access to healthier and their determinants. In total, 1136 women responded food stores (for example, supermarkets) is positively corre- (50% overall, excluding from the denominator 127 women lated with dietary quality (Moore et al., 2008; Zenk et al., who had moved/were ineligible): 354 from high-, 407 from 2009), whereas greater fast-food restaurant access is linked to mid- and 375 from low-socioeconomic status neighbour- more frequent fast-food purchasing (Thornton et al., 2009). hoods. A second independent sample was drawn in the same Evidence from the US and UK on consumer nutrition manner for a separate physical activity survey. Women who environments suggests that in more deprived neighbour- responded to this were asked if they were also willing to hoods, there are fewer healthy choices available within complete the dietary behaviours survey. This second phase of stores (Andreyeva et al., 2008; Franco et al., 2008), and that the study resulted in an additional 444 diet surveys (42% of prices for the same foods are higher (Crockett et al., 1992; those completing the original physical activity survey). Sooman et al., 1993). However, other studies, primarily from Excluding data from 13 women who had recently moved outside of the US, show the reverse (Cummins and out of the study neighbourhoods and 168 women who had Macintyre, 2002; Ball et al., 2009) or otherwise indicate few missing data on one or more of the individual-level study or no differences (Winkler et al., 2006; Latham and Moffat, variables, the final sample size was 1399 (see Table 1). For the 2007). Evidence of associations between within-store factors analysis of consumer nutrition environments, only a subset and diets is also mixed (Giskes et al., 2007; Powell et al., 2009; of data were used (n ¼ 928 women from 35 neighbourhoods Zenk et al., 2009). for greengrocers; n ¼ 1082 women from 37 neighbourhoods Further evidence is required to more clearly establish links for supermarkets), as not every participant had a store within between dietary behaviours, neighbourhood disadvantage 3 km of their home, or the stores within 3 km fell outside of and both community and consumer nutrition environ- the 45 suburb boundaries from within which the consumer ments. This study investigated whether dietary beha- nutrition environment information was collected. viours are patterned by neighbourhood disadvantage, and if so, whether features within local community and con- sumer nutrition environments explain these associations. Measures This is the first study to consider both community and Outcomes. Fruit and vegetable intakes were assessed sepa- consumer nutrition environments as mediators of area-level rately by asking ‘How many servings of (fruit/vegetables) associations. do you usually eat each day?’ (with examples of servings provided). Response options were ‘none’, ‘1 serving’, ‘2 servings’, ‘3–4 servings’ (coded 3.5 for analyses) or ‘5 Subjects and methods servings or more’ (coded 5). These questions were adapted from the Australian National Nutrition Survey, in which they Participants were shown to discriminate between groups with different These analyses are based on 1399 women participating in the fruit and vegetable intakes assessed by 24-h recall. They also Socioeconomic Status and Activity in Women (SESAW) show good test–retest reliability of 0.85 each (Ball et al., study. Study methods have been described previously (Ball 2006). Acceptable (termed ‘high’) fruit and vegetable con- et al., 2008, 2009) and approval for Socioeconomic Status sumption was defined as consuming two or more serves and Activity in Women was obtained from the Deakin daily. Although Australian guidelines recommend five ser- University ethics committee. Women were recruited from vings of vegetables per day, only 5% of our sample consumed the Australian electoral roll (voting is compulsory for all this amount. Respondents were also asked how many meals Australian adults) using a stratified random sampling per week they ate from fast-food restaurants (for example, procedure from 45 neighbourhoods (suburbs) of different pizza, McDonalds), with separate questions for within- levels of disadvantage in Melbourne, Australia. On the basis restaurant consumption and takeaway (at home, work or of the 2001 Census data, the Australian Bureau of Statistics study) consumption. Six response categories were listed assigned suburbs a Socioeconomic Index for Areas (SEIFA) ranging from ‘never’ to ‘6–7 meals per week or more’. score based on the index of relative socioeconomic dis- Responses to the within-store and takeaway were combined. advantage (Australian Bureau of Statistics 2003). The SEIFA The outcome variable was recoded to ‘never’, ‘infrequent’