State-Issued Identification Cards Reveal Patterns in Adult Weight Status.

Background: State-issued identification cards are a promising data source for neighborhood-level obesity estimates.

Methods: We used information from three million Oregon state-issued identification cards to compute age-adjusted estimates of average adult body mass index (BMI) for each census tract in the state. We used multivariate linear regression to identify associations between weight status and population characteristics, food access, commuting behavior, and geography.