Long-term impact of PM2.5 exposure on frailty, chronic diseases, and multimorbidity among middle-aged and older adults: insights from a national population-based longitudinal study.

Particulate Matter 2.5 (PM_2.5) is a significant risk factor for frailty and chronic diseases. Studies on the associations between PM_2.5 and frailty, chronic diseases, and multimorbidity are scarce, especially from large cohort studies. We aimed to explore the potential association between PM_2.5 exposure and the risk of frailty, chronic diseases, and multimorbidity. We collected data from a national cohort (CHARLS) with a follow-up period of 11–18 years, totaling 13,366 participants. We obtained PM_2.5 concentration data from the Atmospheric Composition Analysis Group at Dalhousie University. PM_2.5 exposure is based on the average annual concentration in the prefecture-level city where residents live. We define frailty as the comprehensive manifestation of declining various body functions, characterized by a frailty index of 0.25 or greater, and multimorbidity as the presence of at least two or more chronic conditions. Cox proportional hazards regression was used to estimate the hazard ratio (HR) with its 95% confidence interval (95%CI). A 10-μg/m³ increase for PM_2.5 was significantly associated with an increased risk of frailty (HR = 1.289, 95%CI = 1.257–1.322, P < 0.001). A 10-μg/m³ increase for PM_2.5 was significantly associated with the elevated risk for most chronic diseases. Compared to those with no morbidity or only single morbidity, a 10-μg/m³ increase for PM_2.5 was significantly associated with the elevated risk for multimorbidity (HR = 1.220, 95%CI = 1.181–1.260, P < 0.001). Ambient PM_2.5 exposure is a significant risk factor for frailty, chronic diseases, and multimorbidity, and some measures need to be taken to reduce PM_2.5 concentration and prevent frailty and chronic diseases. [ABSTRACT FROM AUTHOR]