Long-Term Exposure to PM_2.5 and Mortality: A Cohort Study in China

We investigated the association of long-term exposure to atmospheric PM_2.5 with non-accidental and cause-specific mortality in Yinzhou, China. From July 2015 to January 2018, a total of 29,564 individuals aged ≥ 40 years in Yinzhou were recruited for a prospective cohort study. We used the Cox proportional-hazards model to analyze the relationship of the 2-year average concentration of PM_2.5 prior to the baseline with non-accidental and cause-specific mortality. The median PM_2.5 concentration was 36.51 μg/m³ (range: 25.57-45.40 μg/m³). In model 4, the hazard ratios per 10 μg/m³ increment in PM_2.5 were 1.25 (95%CI: 1.04-1.50) for non-accidental mortality and 1.38 (95%CI:1.02-1.86) for cardiovascular disease mortality. We observed no associations between PM_2.5 and deaths from respiratory disease or cancer. In the subgroup analysis, interactions were observed between PM_2.5 and age, as well as preventive measures on hazy days. The observed association between long-term exposure to atmospheric PM_2.5 at a relatively moderate concentration and the risk of non-accidental and cardiovascular disease mortality among middle-aged and elderly Chinese adults could provide evidence for government decision-makers to revise environmental policies towards a more stringent standard.