Impact of long-term exposure to PM2.5 and its components on the risk of chronic lung disease in middle-aged and elderly chinese: evidence from a large Chinese population-based cohort.

Background: Epidemiological evidence indicates a close association between particulate matter with an aerodynamic diameter of fewer than 2.5 μm (PM_2.5) and the occurrence and worsening of chronic lung diseases (CLD), particularly in middle-aged and older adults. Previous studies have explored the effects of PM_2.5 and its components on CLD to a limited extent, and the dynamic trajectories of PM_2.5 and its components over time have not been considered in relation to CLD.

Methods: This study used data from the China Health and Retirement Longitudinal Study (CHARLS) from 2011 to 2018 to explore the relationship between long-term exposure to PM_2.5 and its components (sulfate, nitrate, ammonium, organic matter, and black carbon) and CLD based on generalized linear mixed models (GLMM) and group-based trajectory model (GBTM).

Results: Results reveal a significant positive correlation between long-term exposure to PM_2.5 and its component concentrations, as well as the rate of decline in these concentrations, with the incidence of CLD. For each 1 µg/m³ increase in PM_2.5, black carbon, organic matter, sulfate, nitrate, and ammonium, there was an increase in the risk of chronic lung disease of 1.005 (95% CI: 1.002, 1.009), 1.177 (95% CI: 1.100, 1.259), 1.027 (95% CI: 1.012, 1.042), 1.037 (95% CI: 1.018, 1.056), 1.021 (95% CI: 1.006, 1.037), and 1.028 (95% CI: 1.005, 1.052). Multivariate pollutant mixture analyses using Weighted Quantile Sum Regression and Quantile g-computation regression analysis found that among PM_2.5 components, black carbon, sulfate, and organic matter are more related to the risk of CLD.

Conclusion: This prospective cohort study of middle-aged and older adults in China observed that long-term exposure to various PM_2.5 components increases the risk of CLD. Given the significant role of black carbon, organic matter, and sulfate in their combined harmful effects, stringent controls on the emissions of these components could help mitigate the rising prevalence of CLD among China's rapidly aging population.