Long-term exposure to particulate matter and the risk of stroke in Chinese adults: findings from the China Health and Retirement Longitudinal Study (CHARLS)

Particulate matter (PM) plays a significant role in the global burden of cerebrovascular diseases. This study aimed to investigate the effect of long-term exposure to PM10, PM2.5, and their specific components on the risk of stroke. The cohort study was performed on 7,203 participants aged ≥ 45 years in the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018. Satellite-based estimates combined with machine learning algorithms were used to assess annual concentrations of PM. Cox proportional hazards models and the restricted cubic spline (RCS) analyses were employed to evaluate the associations between individual PM exposure and stroke risk, while a quantile-based g-computation (qg-comp) model was used to estimate the joint effects of PM2.5 components on stroke risk. During 7.88 years of average follow-up (56,734 person-years), 5.1% of participants experienced a stroke. Exposure to PM10 was linearly and positively associated with risk of stroke (adjusted hazard ratios: 1.144, 95% confidence interval [CI]: 1.101–1.188) per 10 µg/m³). Nonlinear associations were found between PM2.5 and its components and stroke (all p for non-linearity < 0.05). The qg-comp analysis showed that a simultaneous one-quantile increase in all PM2.5 components exposures was significantly associated with a 1.439-fold increase in stroke risk, with ammonium, black carbon, and sulfate emerging as the primary contributing components. Long-term exposure to PM10 and PM2.5 was positively associated with stroke risk among Chinese adults. Ammonium, black carbon, and sulfate were identified as the key contributors to the adverse effects of PM2.5 on stroke risk.