Background. The prevalence of obesity and diabetes among U.S. adults has increased steadily over the past several decades while physical activity and dietary intake, two pertinent behaviors, are below recommended guidelines. Previous literature indicates that attributes of the physical environment, including walkability and healthy food availability, are associated with physical activity, dietary intake, obesity and diabetes but little is known if these associations differ by neighborhood race and socioeconomic (SES). Given the racial and SES disparities in obesity and diabetes, this study examined the association between the physical environment and health outcomes by neighborhood race and SES.
Methods. A cross-sectional study was conducted among 3,493 participants from the Healthy Aging in Neighborhoods of Diversity across the Life-Span (HANDLS) study in Baltimore, Maryland. Trained staff collected demographic information, a medical history, height, weight, fasting plasma glucose (FPG) and two 24-hour dietary recalls. The Pedestrian Environment Data Scan (PEDS) was implemented to determine neighborhood walkability in 34 census tracts of varying racial and socioeconomic composition in which participants resided. Results from a previous study were used to impute neighborhood healthy food availability scores. Descriptive statistics, confirmatory factor analysis and multilevel logistic and linear regression were used to investigate walkability and healthy food availability and the association with obesity, diabetes, physical activity and dietary intake by neighborhood race and SES.
Results. Walkability was higher in predominately white neighborhoods compared to predominately black neighborhoods, although this association was not statistically significant; there was no significant association by neighborhood SES. Among individuals living in predominately white and high-SES neighborhoods, residing in highly walkable neighborhoods was associated with a lower prevalence of obesity compared to individuals living in poorly walkable neighborhoods after controlling for demographic variables (PR=0.58, p=<0.001; PR=0.80, p=0.004, respectively). The associations remained significant in these neighborhoods after controlling for main mode of transportation, physical activity and neighborhood crime. Contrary to expectations, among individuals residing in predominately white areas, high availability of healthy foods was associated with significantly higher BMI compared to individuals living in low healthy food availability neighborhoods after adjustment for demographic variables (β=3.22, p=0.001). Associations were attenuated but remained significant after controlling for dietary intake (β=2.81, p=0.012). There were few significant associations between the physical environment and diabetes.
Conclusion. A highly walkable neighborhood was associated with a lower prevalence of obesity among individuals living in predominately white or high-SES neighborhoods. In addition, there was a positive association between the availability of healthy food and higher BMI among individuals living in predominately white neighborhoods. Future research is needed to determine how these differences in associations by neighborhood characteristics may contribute to racial disparities in obesity.