Abstract for the 2018 HEI Annual Conference
Susceptibility to Multiple Air Pollutants in Cardiovascular Disease
1Jane E. Clougherty, 1Jamie L. Humphrey, 2Ellen J. Kinnee, 2Laura D. Kubzansky, 3Colleen E. Reid, 1Leslie A. McClure
1 Drexel University Dornsife School of Public Health, Philadelphia PA, USA; 2 University of Pittsburgh Graduate School of Public Health, Pittsburgh PA; 3 Harvard T.H. Chan School of Public Health, Boston MA, USA
Background. Cardiovascular disease (CVD), the leading cause of death in the U.S., has been linked to chronic and acute air pollution exposures. Research has identified stronger effects of air pollution in lower-socioeconomic position (SEP) communities, where exposures are also often higher. While specific factors underlying this susceptibility remain unknown, chronic psychosocial stress related to social adversity has been hypothesized as a critical component. The potential interplay between social and environmental exposures is particularly relevant for CVD, as both impact upon several common processes in CVD. More clearly elucidating susceptibility factors will help to better identify at-risk populations, to offer methods for investigating joint effects of multiple exposures, and, ultimately, to develop more cost-effective interventions towards reducing disproportionate CVD burdens and health disparities.
Methods. We are quantifying relationships between exposures to multiple pollutants and CVD events in New York City using four unique datasets:  Spatial data on citywide community SEP and stressor indicators;  Surfaces for fine-scale spatial variation in multiple pollutants from NYC Community Air Survey (NYCCAS) [fine particles (PM2.5), nitrogen dioxide (NO2), summertime ozone (O3), sulfur dioxide (SO2)];  Daily ambient pollution concentrations from EPA Air Quality System monitors; [d] Complete data on in- and out-patient unscheduled CVD events presented in NYC emergency departments (EDs) 2005-2011 (n = 1.3 million), from NY State Department of Health Statewide Planning and Research Cooperative System (SPARCS).
Under Aim 1, we used ecologic cross-sectional models to examine spatial relationships among pollutants, stressors, and age-adjusted community CVD rates. For Aim 2, we are examining associations between spatio-temporal pollution exposures and CVD events using case-crossover models, inherently adjusting for non-time-varying individual confounders. In Aim 3, we will test modification in these associations by community SEP and/ or chronic stressor exposures.
Results. Results for Aim 1 suggested that, in ecologic models, social stressors generally explained greater variation in CVD than did pollutants. Further, above-median material deprivation (e.g., poor housing) conferred stronger associations between area-level SO2 and CVD, in the hypothesized direction. Preliminary case-crossover analyses (Aim 2) suggest slightly stronger associations between O3 and CVD in communities with above-median assault rates.
Discussion. Ecologic results from Aim 1 suggested that social stressors may explain more variance in CVD than does ambient air pollution, and that some social stressors may confer stronger associations between pollution and CVD. These observed associations may under-estimate true effects, however, due to the small sample size (n = 34 areas), exposure misclassification for both stressors and pollutants, or complex joint distributions between pollutants and social stressors across NYC. Preliminary results from on-going case-crossover analyses (Aim 2) suggest some potential effect modification by stressors, in case-level relationships between spatio-temporal pollutant exposures and CVD risk.
Poster by Clougherty et al, 2018 HEI Annual Conference