BMI, auto use, and the urban environment in San Francisco.

The epidemic of overweight and obesity has sparked interest in urban planning circles. Many believe the built environment directly influences physical health, and recent empirical evidence supports this notion. Cross-sectional survey data was collected from a sample of San Francisco residents (n=670) in the summer of 2005. Body mass index (BMI) served as the dependent variable. Independent variables included population density and auto use. Results indicate an inverse relationship between density and auto use as well as higher BMI scores for respondents reporting high levels of auto use for the work/school commute and trips to the grocery store.