Neighborhood Food Environment, Dietary Intake, and Body Mass Index among the Adult Population in California

Study Design: Cross-sectional study where food outlet data from infoUSA is geo-coded and mapped to individual-level data from 2005 California Health Interview Survey. ArcMaps is used to construct circular neighborhoods centered at the residences of respondents. Food environment measures are defined as the ratio of the number of food outlets of a specific type to all food outlets in neighborhoods. Outcomes of interest include fruit and vegetable consumption, discretionary calorie intake, and body mass index (BMI). The first two outcomes are hypothesized to be intermediate outcomes relating neighborhood food environment to resident BMI. Multivariate regression models are used to discern effects of food environment from individual characteristics, health behaviors, and neighborhood sociodemographics.

Principal Findings: Food environment is significantly associated with residents' dietary intake and BMI. The presence of at least one supermarket is associated with the likelihood of having five or more daily servings of fruit and vegetables. A greater density of convenience stores and fast food restaurants is positively related respectively to discretionary calorie consumption and higher BMI. There are about four fast food restaurants and convenience stories for every one supermarket or produce vendor in California. An increase of the statewide ratio from 4:1 to 5:1 is associated with an increase in obesity prevalence from 18.7% to 20.2% for women and from 21.5% to 22.2% for men, after accounting for individual and community characteristics.

Conclusions: Food outlets can influence dietary choices and obesity development. Investigation of alternative definitions of food environment may better reflect the choices consumers face in their purchase decisions and consequent health outcomes.