Environment/Climate Change
Exposure-response relationships between chronic exposure to fine particulate matter and hospitalization risks for major cardiovascular diseases Yaguang Wei* Yaguang Wei Yijing Feng Edgar Castro Adjani A. Peralta Joel D. Schwartz
Objective: To estimate exposure-response (E-R) relationships between chronic exposure to fine particulate matter (PM2.5) and risks of first hospitalizations for ischemic heart disease, cerebrovascular disease, heart failure, cardiomyopathy, arrhythmia, valvular heart disease, thoracic and abdominal aortic aneurysms, and composite of these cardiovascular disease (CVD) subtypes.
Methods: We conducted a cohort study within Medicare fee-for-service beneficiaries aged ≥ 65 years in the contiguous US between 2000–2016. For each outcome, participants were followed each year until the first hospitalization, death, or end of study. Estimated PM2.5 levels at ZIP codes were calibrated to reduce exposure error. A causal framework that allowed confounders to have different impacts in different exposure ranges was developed, incorporating uncertainty of exposure estimates to reduce biases from exposure error.
Results: Three-year average PM2.5 exposure was associated with increased relative risks of first hospitalizations for ischemic heart disease, cerebrovascular disease, heart failure, cardiomyopathy, arrhythmia, and thoracic and abdominal aortic aneurysms. For composite CVD, the E-R curve demonstrated monotonically increased risk associated with PM2.5: compared to exposures ≤ 5 µg/m3, the WHO air quality guideline, the relative risk was 1.29 (95% CI, 1.28 to 1.30) at exposures between 9–10 µg/m3, which encompassed the US national average of 9.7 µg/m3. On absolute scale, ischemic heart disease, cerebrovascular disease, heart failure, and arrhythmia presented significantly increased risks associated with PM2.5. The effects persisted at least for three years after PM2.5 exposure. Age, education, healthcare accessibility, and neighborhood deprivation level modified the susceptibility to PM2.5.
Conclusions: No “safe threshold” exists for chronic effect of PM2.5 on CVD. Significant benefits could be attained through compliance with the WHO air quality guideline.
