Thesis (Ph.D.)--University of Rochester. School of Medicine & Dentistry. Dept. of Public Health Sciences, 2013.
Background: Reversing the nation’s childhood obesity epidemic will likely require changes in the retail food environment. Some evidence suggests a relationship between regional food prices and children’s weight, though no study has assessed the effects of local food prices on children’s BMI.
Purpose: To determine 1) the differences in cost between high and low energy density (HED and LED) grocery items, 2) the association of children’s neighborhood race and poverty with their local food prices, and 3) whether children’s BMI z-scores are related to the relative prices of HED and LED items in grocery stores in their communities.
Methods: Commonly-consumed items from a representative sample of children were divided into two “baskets” based on energy density (calories per gram), and costs were compared between the HED and LED baskets. Mean HED:LED cost ratios in grocery stores within 1 and 3 miles of children’s homes were compared across children in neighborhoods of different minority and poverty rates, and multilevel linear regression assessed the relationship of children’s BMI z-scores with their mean local cost ratios.
Results: HED items were significantly more expensive per kilogram (foods), but significantly less expensive per 1000 calories (foods and beverages), per quart (beverages), and per serving (foods and beverages). Neighborhood minority and poverty rates were significantly and negatively associated with children’s local cost ratios, indicating that prices are more favorable toward unhealthful HED purchases in the stores surrounding children in high-minority and impoverished neighborhoods. Interactions between neighborhood poverty and children’s local cost ratios showed that cost ratios that are more in favor of healthful LED purchases were often associated with higher BMI z-scores among children in low-poverty neighborhoods, but with lower BMI z-scores for children in higher-poverty neighborhoods.
Conclusions: Differences in grocery costs across areas of different minority and poverty rates likely contribute to the increased obesity risk among minority and disadvantaged children. Policy interventions may create more of an economic incentive for the purchase of healthful foods and beverages, and targeted educational and behavioral interventions could help consumers more adeptly navigate the “obesogenic” food environment to improve children’s diets and reduce socioeconomic disparities in child obesity.
