Exposure to fine particulate matter constituents increases sarcopenia risk in middle-aged and elderly Chinese adults

BACKGROUND: Growing evidence has underscored the adverse role of air pollutants in the pathogenesis of sarcopenia, while there lacks knowledge over the relationships between PM2.5 constituents and sarcopenia. METHODS: This study included 6666 participants aged 45 years and above from the China Health and Retirement Longitudinal Study in 2011, of which 2538 were followed up until 2015. Average concentrations of PM2.5 and its constituents (sulfate, nitrate, ammonium, organic matter OM, black carbon BC) were retrieved from Tracking Air Pollution in China (TAP) database. In the cross-sectional analyses, we employed multivariate logistic regression, generalized linear model, and restricted cubic spline function to analyze the individual relationships of air pollutants with sarcopenia prevalence and sarcopenia-related index (SI). A lower SI is generally associated with a greater risk of sarcopenia. Quantile-based g-computation model was used to clarify the joint effect of multiple PM2.5 components and their relative weights of contributions. Cox proportional hazard model was established to ascertain the longitudinal impacts of air pollutants on sarcopenia incidence. RESULTS: For each interquartile range increment of PM2.5, sulfate, nitrate, ammonium, OM, and BC, the adjusted ORs for sarcopenia were 1.42 (95% CI, 1,14 to 1.77), 1.42 (95% CI, 1.14 to 1.76), 1.38 (95% CI, 1.09 to 1.75), 1.36 (95% CI, 1.09 to 1.70), 1.35 (95% CI, 1.09 to 1.67), and 1.39 (95% CI, 1.15 to 1.68), respectively. Consistently, we found a negative relationship between air pollutants and SI. Multi-pollutant analyses suggested that sarcopenia risk was linearly associated with exposure mixtures, with sulfate identified as the dominant driver of joint effect. In addition, the findings from concentration-response curves, subgroup analyses, sensitivity analyses, and longitudinal analyses further supported the harm of PM2.5 and its constituents on sarcopenia development. CONCLUSION: Our study demonstrates a positive association of single and joint exposure to PM2.5 and its components with sarcopenia risk, offering additional implications on early screening and management of sarcopenia.