Long-term exposure to PM_2.5 components and cardiovascular admissions in medicare patients

Background: Fine particulate matter (PM_2.5) has been previously linked to cardiovascular diseases (CVDs). PM_2.5 is a mixture of components, each of which has its own toxicity profile which are not yet well understood. This study explores the relationship between long-term exposure to PM_2.5 components and hospital admissions with CVDs in the Medicare population. Methods: We analyzed data from U.S. Medicare fee-for-service beneficiaries between 2000 and 2016. Annual levels of fifteen PM_2.5 components were derived from hyperlocal spatiotemporal models. Our outcomes included hospital admissions with CVDs, and more specifically with myocardial infarction, ischemic stroke, atrial fibrillation, and heart failure. A weighted quantile sum (WQS) approach was used, and stratification analyses examined effect modification by demographic and socioeconomic characteristics. We also restricted the analysis to zip code-years with PM_2.5 levels below 8 μg/m³ to assess effects below current US standards. Results: The analyses showed that higher levels of PM_2.5 were associated with increased hospital admissions for CVDs, particularly heart failure. Each decile increase in PM_2.5 levels increased the rate of CVD admissions by 4.1 % (95 % CI: 4.1 %–4.2 %). Key contributors to these effects included nickel and sulfate. Women and black individuals experienced higher rates of PM-associated CVD admissions, while white and non-Medicaid-eligible individuals had higher rates of stroke, atrial fibrillation, and heart failure admissions. Conclusion: Exposure to PM_2.5 components, particularly nickel and sulfate, increased the risk of CVD hospitalizations in the Medicare population, highlighting the potential to reduce CVD risk by controlling sources like fuel combustion, traffic pollution, industrial pollution, and coal use.