(P22-003-20) Effect of the 2009 WIC Food Package Change on Childhood Obesity Depended on the Neighborhood Food Environment for Girls, but Not Boys, in Los Angeles County, California

Objectives: Food packages provided by the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) were revised in 2009 to better align them with the Dietary Guidelines for Americans, and this food package change was previously linked to a 10-12% reduction in obesity risk among WIC-participating children in Los Angeles County, California. This study was conducted to evaluate whether the effect of the food package change on childhood obesity varied by the food environment in the neighborhoods where WIC-participating children live.

Methods: Administrative data from participating children in Los Angeles County, California (2003-2016) were merged with geocoded food vendor information by neighborhood of residence. Obesity risk at age 4 was compared between children receiving old (2003-2009) and new (2010-2016) WIC food packages using sex-stratified Poisson regression models, with interaction terms between WIC package and neighborhood density (number per square mile) of healthy (supermarkets, grocery stores, farmers markets), and unhealthy (convenience stores, fast food restaurants, liquor stores) food outlets.

Results: The new food package was associated with significantly lower obesity risk. Among boys, the new food package was associated with 8 to 18% lower obesity risk at all healthy and unhealthy food outlet densities, and the association was not modified by neighborhood food outlet density. Among girls, the association of the new food package with obesity risk was protective in neighborhoods with high density of healthy and low density of unhealthy food outlets, and adverse in neighborhoods with high density of unhealthy and low density of healthy food outlets. The effect of the new food package among girls was modified by unhealthy food outlet density, with significantly smaller (p-value=0.004) decreases in obesity risk observed in neighborhoods with higher unhealthy food outlet density.

Conclusions: The impact of the food package change was modified by the neighborhood food environment among girls.  It remains important to identify differential effects of policy changes for young boys versus girls and to explore how future policy changes might mitigate inequitable impacts arising from the neighborhood food environment. 

Funding Sources: The study was funded by the American Heart Association.