Air Pollution and Cardiovascular Disease in American Indian Communities

ABSTRACT Increasing evidence indicates that air pollution is a relevant risk factor for cardiovascular disease (CVD) even at low exposure levels. American Indian populations experience the highest burden of CVD compared to other racial/ethnic groups in the US and thus may be particularly vulnerable to air pollution. Further, although air pollution exposure levels have decreased in recent decades in the general US population, these decreases are less pronounced in American Indian populations, suggesting environmental disparities in air pollution mitigation. However, there is currently a lack of relevant data to comprehensively characterize air pollution levels, components, and sources in American Indian and other rural populations, which are needed to inform effective mitigation and intervention strategies. We propose to study the associations of air pollution exposure with CVD as well as with subclinical risk factors for CVD (blood pressure) in American Indian communities in the Southwest and Great Plains. We will leverage data from the NHLBI-funded Strong Heart Study (SHS) cohort to study short-term and long-term cardiovascular effects of air pollution in American Indian communities. Aim 1: We will characterize ambient air pollution via measurements and spatio-temporal modeling in the three SHS study regions (Arizona, Oklahoma, North and South Dakota). For four years, we will use filters and pumping boxes at a central site in each study region to obtain two-week average concentrations of ambient fine particulate matter (PM2.5) and its components including black and organic carbon, metals, and acids. We will also obtain two-week averages of ozone (O3) levels using passive samples. In a subset of 240 SHS participants (80 per region) in three different seasons, we will measure ambient real-time PM2.5 levels for one week. Our measurements and other available PM2.5, nitrogen dioxide (NO2), and O3 data will be used to build spatio-temporal air pollution models for SHS regions. Source apportionment will be used to identify pollution sources. Aim 2: We will determine short-term cardiovascular effects of air pollution exposure in these communities. We will evaluate associations between ambient PM2.5 levels and composition, NO2, and O3 (from Aim 1) with measures of ambulatory blood pressure monitoring in 240 SHS participants in three repeated measurements over 18 months. Aim 3: We will determine long-term cardiovascular effects of ambient air pollution exposure. We will evaluate associations between long-term exposure to PM2.5, NO2, and O3 (estimated with our model in Aim 1) and incident CVD (coronary heart disease, stroke, heart failure) in the SHS cohort (N = 2,736) and its family expansion (N = 2,769) using high-quality data for 2000–2024. This study will comprehensively characterize air pollution exposures and associations with clinical CVD outcomes in American Indian and rural populations. Our data will provide critical data needed to inform National Ambient Air Quality Standards, ultimately contributing to strategies to mitigate the adverse health effects of low-level air pollution exposures especially in already vulnerable populations including American Indians.