Introduction: Exposure to PM2.5 air pollution and neighborhood-level sociodemographic characteristics are associated with cardiovascular disease and possibly diabetes. However, the joint effect of sociodemographics and PM2.5 on these outcomes is uncertain.
Methods: We examined whether clusters of sociodemographic characteristics modified effects of long-term PM2.5 exposure on coronary artery disease (CAD), myocardial infarction (MI), hypertension, and diabetes. We used medical records data from 2192 cardiac catheterization patients residing in North Carolina and assigned to one of six previously-determined clusters. For each participant, we estimated annual PM2.5 exposure at their primary residence using a hybrid model with a 1 km2 resolution. We used logistic regression models adjusted for age, sex, body mass index, and smoking status, to assess cluster-specific associations with PM2.5 and to determine if there were interactions between cluster and PM2.5 on outcomes.
Results: Compared to cluster 3 (OR 0.93, 95% CI 0.82-1.07; urban, low proportion of black individuals and high socioeconomic status), we observed greater associations between PM2.5 and hypertension in clusters 1 (OR 1.22, 95% CI 0.99-1.50, pint 0.03) and 2 (OR 1.64, 95% CI 1.16-2.32, pint 0.003), which were urban, high proportion of black individuals, and low socioeconomic status. PM2.5 was associated with MI (OR 1.29, 95% CI 1.16-1.42) but not diabetes, regardless of cluster and was associated with CAD in cluster 3 (OR 1.15, 95% CI 1.00, 1.31) and overall (OR 1.07, 95% CI 0.98, 1.17).
Discussion: Areas of relative disadvantage have a stronger association between PM2.5 and hypertension compared to areas of relative advantage.