Objective: The goal of this study was to explore neighborhood environmental factors associated with obesity in a sample of adults living in a major U.S. metropolitan area.
Research methods and procedures: This was a multi-level study combining data from the U.S. Behavioral Risk Factor Surveillance System with data from the U.S. Census. A total of 15,358 subjects living in 327 zip code tabulation areas were surveyed between 1998 and 2002. The outcome was obesity (BMI >30), and independent variables assessed included individual level variables (age, education, income, smoking status, sex, black race, and Hispanic ethnicity), and zip code level variables (percentage black, percentage Hispanic, percentage with more than a high school education, retail density, establishment density, employment density, population density, the presence of a supermarket, intersection density, median household income, and density of fast food outlets).
Results: After controlling for individual level factors, median household income [relative risk (RR) = 0.992; 95% confidence interval (CI) = 0.990, 0.994], population density (RR = 0.98; 95% CI = 0.972, 0.990), employment density (RR = 1.004; 95% CI = 1.001, 1.009), establishment density (RR = 0.981 95% CI = 0.964, 0.999), and the presence of a supermarket (RR = 0.893; 95% CI = 0.815, 0.978) were associated with obesity risk. Fast food establishment density was poorly associated with obesity risk.
Discussion: Where one lives may affect obesity status. Given the influence of the presence of a supermarket on obesity risk, efforts to address food access might be a priority for reducing obesity.