Is the local food environment related to obesity and dietary behavior? It may depend on how you characterize the food environment

Background: A growing body of research has examined the association of food environments with health outcomes such as obesity or dietary behavior. However, this research has produced inconsistent results with a number of studies finding that food environments are associated with obesity and dietary behavior and others reporting no association. We examined whether different ways of characterizing the food environment impacts these associations. Methods: Using data from the 2007 California Health Interview Survey, we examined the association of the food environment around respondents' households with adult obesity and dietary behaviors. Food environments were characterized in two ways: (1) counts of particular types of food stores including fast-food restaurants, convenience stores, dollar stores, liquor stores, grocery stores, produce vendors, and warehouse stores; and (2) the Retail Food Environment Index (RFEI), a proportional measure that attempts to characterize the overall food environment. The RFEI is defined as the number of businesses offering primarily unhealthy food options divided by the number offering healthier food options. Results: Regression models adjusting for age, gender, race/ethnicity, income, and individual food outlet types revealed few significant associations between any individual store type and the outcomes. Conversely, the RFEI was positively associated with obesity as well as consumption of sugar-sweetened beverages and fast food, but inversely associated with fruit and vegetable consumption. Conclusions: These findings suggest that how the food environment is characterized in research can impact conclusions drawn about the association of food environments with health outcomes.