Neighborhood Walkability and Cardiovascular Risk in the United States

Neighborhood walkability may be associated with increased physical activity and thus may confer protection against cardiovascular disease and associated risk factors. We sought to characterize the association between neighborhood-level cardiovascular diseases and risk factors with neighborhood walkability across US census tracts.We linked the Centers for Disease Control and Prevention (CDC) PLACES dataset which provided census-tract level prevalence of coronary artery disease (CAD) and cardiovascular risk factors (hypertension, high cholesterol, obesity, and diabetes), with census tract population-weighted national walkability index (NWI) from the US Environmental Protection Agency (EPA). We calculated the mean prevalence of each cardiovascular health indicator per quartile of the walkability score. We also fit a multivariable linear regression model to estimate the association between walkability index and the prevalence of CAD adjusting for age, sex, race, and the CDC'S social vulnerability index, an integrated metric of socioeconomic position. We additionally performed mediation analyses to understand the mediating effects of CAD risk factors on the relationship between NWI and CAD prevalence. A total of 70,123 census tracts were analyzed nationwide. Across walkability quartiles Q1 (least walkable) through Q4 (most walkable), we found statistically significant decrease in the prevalence of CAD (7.0% to 5.4%), and risk factors including hypertension (35.5% to 29.7%), high cholesterol (34.5% to 29.2%), obesity (35.0% to 30.2%), and diabetes (11.6% to 10.6%). After multivariable adjustment, continuous walkability index was negatively and significantly associated with the prevalence of CAD (β = -0.09, P<0.0001). The relationship between NWI and CAD is partially mediated by the risk factors. High cholesterol accounted for 45%, high blood pressure 41% and diabetes 10% of the total effect of walkability on CAD. While direct relationship between walkability and CAD accounted for 9% of the total effect. This nationwide analysis demonstrates that neighborhood walkability is associated with a lower prevalence of cardiovascular risk factors and CAD. The association between NWI and CAD seems to be partly mediated by prevalence of traditional risk factors.