On 24 July, an international team of researchers published an article on air pollution and dementia risk in The Lancet Planetary Health journal. Researchers conducted a systematic review of primary observational studies of adults in MEDLINE, Embase, Cochrane Library, CINAHL, Global Health, PsycINFO, Scopus, and Web of Science Core Collection for studies published until October 2023. After application of the in- and exclusion criteria they conducted a meta-analysis of 32 observational studies including over 24 million participants. They extracted harmonised effect estimates for pollutants when reported by three or more independent studies. Risk of bias was mostly low and the overall certainty of the evidence was assessed as moderate. The study confirms a significant association between long-term exposure to certain air pollutants and increased risk of dementia.
A strong link was found for fine particulate matter (PM2.5), with a pooled hazard ratio of 1.08 per 5μg/m³ increase in exposure. Associations were also found for nitrogen dioxide (HR 1.03 per 10μg/m³) and black carbon (HR 1.13 per 1μg/m³). No significant association was found for PM10, nitrogen oxides or annual ozone. The authors conclude that reducing exposure to air pollution could lower dementia incidence and that stricter air quality standards would likely benefit public health and reduce societal costs. The article has been published open access and can be read here: https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(25)00118-4/fulltext
