Long-term exposure to PM2.5 and all-cause mortality: ten-year follow-up of a multicentre population-based prospective study among rural Chinese population

Background The adverse effects of long-term exposure to particulate matter (PM _2.5 ) have been found to be closely associated with mortality. However, the relevant research on different exposure levels in rural areas is insufficient in China. Methods Based on a multicenter population-based prospective study, the adult rural residents (≥ 15 years old) from three study sites with different PM _2.5 exposure levels were tracked for the death events between 2013 and 2023. The estimated values of satellite remote sensing within 1km of the participants' residences were aggregated to evaluate the long-term exposure concentration level of each participant to PM _2.5 . The Cox proportional hazards model was used to assess the influence of long-term exposure to PM _2.5 on all-cause and specific cause mortality. Results 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 m ^− 3 increase of it. In Zhongmu County where with the highest median PM _2.5 concentration of 68.9 µg m ^− 3 , the impact of PM _2.5 on mortality was higher than that in Xiangtan site and Longxi site, with an adjusted HR of 3.52 (95%CI: 3.19–3.88). Importantly, the strength of this association varied corresponding to the specific cause of mortality. Conclusion Our results indicate that the long-term PM _2.5 exposure is associated with an increased risk of all-cause mortality in rural China, and such a correlation shows regional differences. It suggests that the balance of resource commitment in environmental improvement is also of great significance for controlling health problems such as tuberculosis (TB).