Clean Air Act mitigate the cognitive deterioration in older adults

Background: Air pollution may accelerate cognitive ageing; it is unclear whether large-scale interventions by Clean Air Act can mitigate the cognitive deterioration. We evaluated the impact of China’s Clean Air Act (CCAA) on changes of cognitive function in older adults. Methods: In this quasi-experimental study, we conducted a difference-in-differences analysis based on Chinese Longitudinal Healthy Longevity Survey during 2014 and 2018. Intervention group came from where the government set a strict target of reducing air pollution, whereas control group lived in areas without reduction target. Global cognitive functions were measured using the Mini-Mental State Examination (MMSE). Findings: We found the intervention group with implementing Clean Air Act had a significantly smaller decline in MMSE score compared to the control group. Interquartile increases in PM2.5 and SO2 concentrations were significantly associated with a faster decline of MMSE score by 1.78 and 0.92 points, respectively. Interpretation: Implementing stringent clean air policies, especially in low- and middle-income countries may mitigate the risk of cognitive aging in older people. Funding Information: This work was supported by the National Key R&D Program of China (2018YFC2000400, 2017YFC1311100), National Natural Sciences Foundation of China (81903392, 81941021), China Postdoctoral Science Foundation funded project (2019M650359), the U.S. National Institute on Aging, National Institutes of Health (P01AG031719), the Duke/Duke-NUS Collaboration Pilot Project, and PKU-Baidu Fund. Declaration of Interests: The authors declare that they have no competing interests. Ethics Approval Statement: We used data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), a prospective cohort study on the determinants of healthy aging and longevity among older population (≥ 60 years) in China. CLHLS was approved by the Biomedical Ethics Committee, Peking University (IRB00001052–13074). All participants provided written informed consent prior to participation.