Associations of outdoor fine particulate air pollution and cardiovascular disease: Results from the Prospective Urban and Rural Epidemiology Study in China (PURE-China)

Background: Evidence on whether an excess risk of incidence and mortality of cardiovascular disease (CVD) among people exposed to a high level of ambient PM2.5 in low-and middle-income countries (LMICs) is lacking. This study aimed to investigate the associations between long-term exposure to ambient fine particulate matter<2.5 mu m (PM2.5) concentrations and the risk of incidence and mortality of CVD in a large cohort study from 115 communities.Methods: In this cohort study, we followed 42 160 adults aged 35-75 years at baseline who enrolled in the Prospective Urban and Rural Epidemiology Study conducted in China (PURE-China) between 2005 and 2009 with ambient PM2.5 estimates, and followed up until August 2021. Cox proportional hazards frailty models were used to estimate the associations between long-term mean outdoor PM2.5 concentrations and CVD events, CVD mortality, and all-cause mortality.Findings: During a median follow-up period of 11.8 years, we documented 2 190 deaths, including 732 CVD deaths. There were 4 559 (10.8 %) of 42 160 participants who experienced incident total CVD, among them there were 861 myocardial infarctions (MI) and 2 338 S. The 3-year median concentration of ambient PM2.5 before the cohort commencement was 52.7 mu g/m3 (interquartile range [IQR] 30.3-74.6). In full adjusted model, a 10 mu g/m3 increase in PM2.5 was associated with a hazard ratio (HR) of 1.12 (95 % CI 1.11-1.14) for major CVD and 1.03 (95 % CI 1.01-1.05) for all-cause mortality. Besides, long-term PM2.5 concentrations had a significantly positive gradient association with total CVD and a similar pattern of associations with other CVD outcomes was observed.Interpretation: This study demonstrated that long-term ambient PM2.5 concentrations is positively associated with increased risks of CVD in adults aged 35-70 years from China. This finding reinforces the need for policymakers to adopt more effective strategies to improve air quality.