Contribution of the neighborhood environment to cross-sectional variation in long-term CVD risk scores in the Framingham Heart Study

Few studies of the health impact of the built environment have examined downstream outcomes, such as cardiovascular disease. We analyzed the neighborhood-level proportional variance in the 10- and 30-year Framingham risk scores (FRS) in the Framingham Heart Study. Our analysis included 3,103 Offspring- and Generation 3 cohort participants 20–74 years old, inhabiting private residences in Massachusetts geocoded to neighborhoods (defined as 2000 US Census block groups) containing the residences of ≥5 participants. The outcome variables were log-transformed to mitigate the effects of the non-normal distributions. In order to remove the possible effects of neighborhood clustering by age and sex, we analyzed residuals of the transformed FRS regressed upon age and sex. Neighborhood-level intraclass correlations (ICCs) and 95% confidence intervals (CIs) of age- and sex-independent, log-transformed FRS were estimated using multilevel linear regression. Individual- and neighborhood-level variables were then added to models to evaluate their influence on ICCs. Analyses were repeated stratified by sex. Among 2,888 participants living in 187 neighborhoods, 1.73% (95% CI: 0.62, 4.72%) of the variance in 10-year FRS was explained at the neighborhood level. The neighborhood ICC was 2.70% (95% CI: 0.93, 7.56) among women but 0.23% (95% CI: 0.00, 99.47%) among men. In the analysis of the neighborhood-level variances in 30-year FRS among 2,317 participants residing in 164 neighborhoods, the ICCs were 3.31% (95% CI: 1.66, 6.47%), 6.47% (95% CI: 3.22, 12.58), and 0.74% (95% CI: 0.01, 33.31), among all participants, women, and men, respectively. In our homogenous middle-class white population in Massachusetts, residential neighborhoods explained a small proportion of the variance in CVD risk.