Distribution of food providers in Cook County: Relationship to socio-economic characteristics and premature mortality at the neighborhood level

The food environment is but one of many environmental conditions that may affect health outcomes and neighborhood-level variation in availability of healthy foods has been documented in a range of studies. This analysis evaluates the hypothesis that areas of Cook County with poor food access have higher premature mortality rates independent of social and economic factors. We utilized GIS mapping techniques to calculate a food access measure for all Cook County census tracts. The measure is based on the inverse distance from each population weighted centroid to all categorical food vendors within the study area. An ordinary least squares regression is then used to account for influence of population density on food access. We conducted a multivariate regression with premature mortality rate as the response variable and food access density measures as independent variables. The control variables are percent of the population under 35, percent below 150% of the federal poverty limit, percent without a high school education, percent Hispanic, percent Caucasian, and unemployment rate. Access to chain supermarkets remained a significant predictor of premature mortality in the presence of these control variables. The regression analysis provides support for the hypothesis that Cook County neighborhoods with a poor food environment – that is areas with low access to supermarkets and/or large independent grocers—tend to have higher premature mortality rates than would be predicted based solely on the age, race/ethnicity, income and education of residents and the employment rate of the area.