Particulate air pollution and effects on cardiovascular health in American Indian communities

PROJECT SUMMARY/ABSTRACT Air pollution is a key environmental determinant of cardiovascular health, yet most studies have been conducted in predominantly white, non-rural populations. Evidence elucidating this exposure-response relation- ship is limited for rural, American Indian tribal communities primarily located in regions with air pollution levels below the current National Ambient Air Quality Standards (NAAQS). To address this research gap, we intend to compare ambient fine particulate matter (PM2.5) concentrations in American Indian communities to the rest of the United States (US) and estimate the associations between PM2.5 and incident cardiovascular disease (CVD) in tribal communities located in the Northern Great Plains (North/South Dakota), Southern Great Plains (Okla- homa), and American Southwest (Arizona), leveraging data from the NHLBI-funded Strong Heart Study (SHS) cohort. We will: 1) estimate concentrations of the six PM2.5 constituents contributing the most to total PM2.5 mass (sulfate, nitrate, ammonium, organic matter, black carbon, and dust) over time in largely AI-populated counties compared to other US counties using existing well-validated, highly spatially resolved satellite-based models; 2) evaluate the association of long-term exposure to a) total PM2.5 and b) six PM2.5 constituents with incident CVD, measuring the effect of PM2.5 exposure on any incident CVD and specific CVD outcomes separately (coronary heart disease (CHD), heart failure, stroke); 3) assess effect modification of the association between total PM2.5 exposure on incident CVD by diabetes status in the SHS and conduct an exploratory analysis of effect modification by metabolic syndrome (MetS), diagnosed in SHS participants who meet at least three of five con- ditions: (1) high waist circumference, (2) high triglyceride level, (3) low HDL cholesterol, (4) high blood pressure, and (5) high fasting blood glucose. Estimating ambient PM2.5 trends in AI communities across the contiguous US and quantifying PM2.5 ex- posure effects on incident CVD risk in the SHS will help advance understanding of environmental health burdens faced in socially disadvantaged communities. Our findings can be used to promote evidence-based prevention and intervention at various scales, from local to national. This work can help inform community-based interven- tions within AI communities to decrease PM2.5 levels and improve cardiovascular health outcomes and prioriti- zation of equitable representation in future iterations of NAAQS.