There is growing concern regarding air pollution as a modifiable risk factor for cognitive impairment, dementia, Alzheimer’s disease, and Parkinson’s disease. We conducted an umbrella review to collate the available evidence from systematic reviews and meta-analyses investigating the association between exposure to air pollution and risk of late-life neurodegenerative disorders. A narrative overview and visual summary of the findings from both quantitative and qualitative reviews are presented. A range of air pollutants were assessed in the included meta-analyses; however, only exposure to fine particulate matter (PM_2·5) was significantly associated with increased risk of cognitive impairment and Alzheimer’s disease. Although associations between exposure to air pollution and late-life neurodegenerative disorders are frequently reported at the individual study level, as seen in the qualitative summary of findings, attempts to quantitatively synthesise these findings generally resulted in suggestive support for the strength of the associations. Over- or underestimation of effect size is possible in view of the wide variation in methodologies used across individual studies. Recommendations for improvements in design, analysis, and reporting as summarised in the present review should be considered when planning future studies to increase the consistency, comparability, and utility of their findings.

人们越来越担心空气污染是导致认知障碍、痴呆、阿尔茨海默病和帕金森病的可改变风险因素。我们进行了一项总括审查，以整理来自调查暴露于空气污染与晚年神经退行性疾病风险之间关联的系统审查和荟萃分析的现有证据。提供了定量和定性审查结果的叙述性概述和视觉总结。在纳入的荟萃分析中评估了一系列空气污染物；然而，仅暴露于细颗粒物（PM _2·5) 与认知障碍和阿尔茨海默病的风险增加显着相关。尽管暴露于空气污染与晚年神经退行性疾病之间的关联经常在个体研究层面上报告，如研究结果的定性总结所示，但尝试对这些研究结果进行定量综合通常会为关联强度提供暗示性支持。鉴于各个研究中使用的方法存在很大差异，可能会高估或低估效应量。在规划未来的研究以提高其研究结果的一致性、可比性和实用性时，应考虑本综述中总结的设计、分析和报告改进建议。