Associations of PM2.5 and its major chemical components with cognitive function: A nationwide prospective cohort study among middle-aged and older adults in China.

ObjectiveThis study aimed to investigate the associations between fine particulate matter and its major chemical components and cognitive function among middle-aged and older adults in China.MethodsWe conducted a nationwide prospective cohort study using data from the China Health and Retirement Longitudinal Study (2011-2018). Cognitive function was repeatedly assessed through standardized tests of memory and mental status. Annual average concentrations of fine particulate matter and its five major components (sulfate, nitrate, ammonium, black carbon, and organic matter) were estimated at the city level. Fixed-effects models and restricted cubic spline analyses were used to evaluate associations, and random forest models were used to rank the relative importance of components.ResultsHigher exposure to fine particulate matter and several of its major components was significantly associated with lower cognitive scores. Among these components, sulfate exhibited the strongest adverse association with cognitive function. The findings were consistent across multiple sensitivity analyses, including those restricted to provincial capitals and those adjusting for potential confounders.ConclusionsExposure to fine particulate matter and its chemical components may contribute to cognitive impairment among middle-aged and older adults in China. Sulfate appears to be particularly detrimental. These results highlight the need for targeted air pollution control policies that address specific fine particulate matter components to mitigate the burden of cognitive impairment.