Source-Specific PM_2.5 and Atherosclerotic Cardiovascular Disease Mortality.

Abstract

Fine particulate matter (PM_2.5) exposure is adversely linked to atherosclerotic cardiovascular disease (ASCVD). However, most studies focused on PM_2.5 mass rather than its chemical composition and specific sources. Particulate pollution sources can have distinct, cumulative, and potentially synergistic health impacts. We investigated the associations of source-specific PM_2.5 exposure with ASCVD mortality in the United States, considering the combined associations and regional variations. We used data from the Centers for Medicare & Medicaid Services (including data from 65,838,403 participants) from 2000 to 2016. We estimated PM_2.5 exposure using machine-learning models and attributed components to five source categories. We used Poisson survival models to assess the associations with the source categories. Higher ASCVD mortality rate (rate ratio [95% confidence interval (CI)] per interquartile range increase) was associated with oil combustion (1.051 [1.049 to 1.052]), industrial pollution (1.054 [1.052 to 1.056]), coal and biomass burning (1.065 [1.062 to 1.067]), and motor vehicle pollution (1.044 [1.042 to 1.046]). These associations persisted even after limiting our sample to ZIP code-years with PM_2.5<9 μg/m³ - the current National Ambient Air Quality Standard. In these areas the observed rate ratio for a one-unit increase in PM_2.5 mass was 1.028 (95% CI, 1.026 to 1.029). We found higher ASCVD mortality rate associated with PM_2.5, with differential effects across sources. These data highlight the importance of considering local population characteristics and exposure patterns when assessing health risks associated with PM_2.5.