This study examined the relationship between neighborhood food stores and a child's body size. We found that in the inner-city, minority community of East Harlem, New York, presence of convenience stores on the block in which a child resides is associated with increased risk for childhood obesity as measured by BMI. These findings are supported by Powell et al. who found that greater availability of convenience stores in school Zip codes was significantly associated with higher BMI among 8th- and 10th-grade students15
and Morland et al who demonstrated similar findings in adults.22
Convenience stores provide ample opportunities for children to purchase and consume energy-dense foods. Several studies have reported that convenience stores lower healthy food consumption among children. Timperio et al. found that among 5-6 and 10-12 year-old Australian children, the more convenience stores located close to a child's home, the lower the likelihood of consuming fruit 2 or more times per day.14
Similar findings have been reported for boys ages 10-14 years old.23
There are several limitations to our study in addition to a small sample size, which we noted earlier. First, we were interested in the food environment of the Census block in which a child resides. When studying the impact of the food environment on BMI, it remains unclear what geographic boundaries are most precise for examining a child's food habits. Geographic areas thus far used in research include the Census Block, Census Tract, Zip code or defined “buffer” zones that are within walking distance from the primary residence. Each of these geographic boundaries has intrinsic limitations. By restricting analyses to the Census block, we did not consider adjacency, i.e. food stores that were available on a neighboring block to where a child resides. Still, it remains significant that 55% of the children in our study had a convenience store and 41% had a fast food restaurant on the block in which they reside.
Analysis restricted to the Census block level provides a limited assessment of the entire scope of food environment exposures in a child's day to day life. We did not account for (1) exposures to food stores at different points in the course of a child's day, i.e. en route to and from school and after-school activities, (2) individual behaviors including frequency with which children are purchasing from stores on their block of residence, or (3) quantity and/or quality of purchases children are making at various food stores.
To deepen our understanding of how food store availability shapes a child's dietary behavior, further studies are needed across all racial/ethnic groups, socio-economic demographics, and geographic areas including urban, suburban, and rural settings to explain children's daily travel, purchasing, and consumption patterns in relation to the local food environment. Factors to explore in future research include what types of foods are available in stores and how they are displayed, advertised, and priced. These data would further enhance support for our findings that suggest that children who live near convenience stores may be at increased risk for obesity due to increased exposure to unhealthy foods.
Interestingly, we observed no statistically significant associations between a child's BMI and the number of fast food restaurants on a child's Census block. Existing studies that examined fast food restaurant availability report similar results.24,25
One issue is the classification of food stores and it remains unclear which elements are essential to defining food store types.
In summary, we found that convenience stores located on the Census block in which a child resides may influence a child's risk for obesity. This suggests that in addition to interventions targeting individuals, there is a role for community level changes to address the obesity epidemic. Every public health success over the course of the past several decades has employed a multifaceted approach. Novel approaches to tackling obesity have targeted access to unhealthy snacks. Some examples include: eliminating vending machines from schools nationwide, requiring fast food restaurants to post calorie counts, partnering with convenience stores to encourage stocking low-fat milk, reducing prices on healthy food items, and offering coupons to encourage shopping at green markets. Longitudinal studies examining the influence of neighborhood food stores can inform multifaceted obesity interventions that combine counseling families on children's neighborhood food purchasing behaviors with innovative food policy initiatives and urban planning that promote healthy communities.