Long-term exposure to PM 2.5 and all-cause mortality: 10-year follow-up of a multicentre population-based prospective study among rural Chinese population

Explore the relationship between long-term PM2.5 exposure and all-cause mortality in different rural areas of China. Based on a multicenter population-based prospective study, the adult rural residents (≥15 years old) from three study sites with different PM2.5 exposure levels were tracked for the death events between 2013 and 2023. The Cox proportional hazards model was used to assess the influence of long-term exposure to PM2.5 on all-cause and specific cause mortality. A total of 12,777 participants were included in the analyses. During the 10-year follow-up, and the risk of all-cause mortality increased 4% (HR = 1.04, 95% CI: 1.03-1.05) for every 1 μg/m3 increase of it. In Zhongmu County where with the highest median PM2.5 concentration of 68.9 μg/m3, the impact of PM2.5 on mortality was higher than that in Xiangtan site and Longxi site (HR = 3.52, 95%CI: 3.19-3.88). Importantly, the strength of this association varied corresponding to the specific cause of mortality. The long-term PM2.5 exposure is associated with an increased risk of all-cause mortality in rural China, and shows regional differences.