Air pollution increases the risk of frailty: China Health and Retirement Longitudinal Study (CHARLS)

The longitudinal association between multiple air pollutants and frailty risk remains unexplored, and it is unclear which factors may modify this relationship. Using data from 10,584 Chinese adults aged 45 years and older in the 2011-2020 waves of the China Health and Retirement Longitudinal Study (CHARLS), we investigated whether exposure to PM₁, PM_2.5, PM₁₀, O₃, and NO₂ affects frailty over a median follow-up of seven years. Air pollutant data were obtained from the China High Air Pollutants (CHAP) dataset, and frailty was assessed using a 44-item Frailty Index (FI ≥ 0.25). Time-varying Cox proportional hazards models, adjusted for demographic, socioeconomic, and behavioral factors, indicated that each 10 μg/m³ increase in PM₁, PM_2.5, PM₁₀, and NO₂ corresponded to a 7.8 %, 4.2 %, 3.8 %, and 12.9 % higher risk of frailty, respectively, while O₃ showed no significant association. Individuals who were sufficiently active appeared less affected by pollution, whereas those with no formal education were more vulnerable. Implementing future policies and interventions to reduce air pollution can potentially decrease the risk of frailty and promote healthy ageing.