Long-Term Exposure to Fine Particulate Matter and Cardiovascular Disease in China

Background: Evidence of the effects of long-term fine particulate matter (PM) exposure on cardiovascular diseases (CVDs) is rare for populations exposed to high levels of PM in China and in other countries with similarly high levels. Objectives: The aim of this study was to assess the CVD risks associated with long-term exposure to PM in China. Methods: A nationwide cohort study, China-PAR (Prediction for Atherosclerotic Cardiovascular Disease Risk in China), was used, with 116,972 adults without CVD in 2000 being included. Participants were followed until 2015. Satellite-based PM concentrations at 1-km spatial resolution during the study period were used for exposure assessment. A Cox proportional hazards model with time-varying exposures was used to estimate the CVD risks associated with PM exposure, adjusting for individual risk factors. Results: Annual mean concentrations of PM at the China-PAR sites ranged from 25.5 to 114.0 μg/m. For each 10 μg/m increase in PM exposures, the multivariate-adjusted hazard ratio was 1.251 (95% confidence interval: 1.220 to 1.283) for CVD incidence and 1.164 (95% confidence interval: 1.117 to 1.213) for CVD mortality. The slopes of concentration-response functions of PM exposure and CVD risks were steeper at high PM levels. In addition, older residents, rural residents, and never smokers were more prone to adverse effects of PM exposure. Conclusions: This study provides evidence that elevated long-term PM exposures lead to increased CVD risk in China. The effects are more pronounced at higher PM levels. These findings expand the current knowledge on adverse health effects of severe air pollution and highlight the potential cardiovascular benefits of air quality improvement in China and other low- and middle-income countries.