The long arm of childhood: The association between early-life indoor air pollution exposure and cognitive performance in later life

A large number of poor people all over the world rely on solid fuels, such as coal and wood, for cooking, directly bringing exposure to indoor air pollution. This exposure has been linked to decreased cognitive performance in later life. However, relatively little is known about the long-term effects of early-life indoor air pollution exposure and how this association varies in different population groups and its mechanisms. This study used nationally representative data of 7,161 adults aged 45 or older in China. Causal forest approach was applied to capture the complex nonlinear relationships and estimate the average treatment effect of early-life indoor air pollution exposure on later-life cognitive performance. Additionally, we estimated heterogeneous associations across subgroups. The results demonstrated that, after allowing for covariates, early-life indoor air pollution exposure was associated with poorer later-life cognitive performance (-1.11; 95% CI [-1.15, -1.07]). Biological and socioeconomic pathways, but not psychological pathway, mediated the negative association. For specific domains of cognitive performance, we found this exposure both significantly associated with worsen performance of episodic memory and mental intactness. The heterogenous analysis further revealed that men, individuals with a history of smoking, and those with a history of alcohol consumption were more vulnerable to the long-term detrimental effects of early-life indoor air pollution exposure on cognitive performance. Our findings suggest a need to improve access to clean energy, such as electricity and gas, which may prevent cognitive impairments from the upstream. • The first study linking early-life indoor air pollution exposure to later-life cognition. • Early-life indoor air pollution was associated with poorer cognitive performance. • BMI, ADL limitations, education and income mediated the association. • The associations were heterogeneous across gender, individuals with a history of smoking and alcohol consumption. • We used nationally representative data of adults aged 45 or older.