Alzheimer's & Dementia · Mar 2026

The sex-specific association between long-term PM2.5 exposure and incident dementia in community-dwelling older adults in Australia

By Zhou A, Zhou Z, Yu W et al.

INTRODUCTION: Air pollution is linked to dementia, but evidence from low-exposure settings is limited. We examined sex-specific associations between long-term exposure to fine particulate matter ≤2.5 µm in diameter (PM2.5) and dementia risk in older adults living in Australia. METHODS: In 16,145 dementia-free Aspirin in Reducing Events in the Elderly (ASPREE) participants (≥70 years; median follow-up 10.3 years), Cox models assessed associations between 1-year mean PM2.5 (continuous and guideline-based categories) and incident dementia, adjusting for demographic, lifestyle, environmental, and genetic factors. Subgroup analyses by sex, apolipoprotein E genotype (APOE), and age were conducted. RESULTS: Overall associations were null, but with a trend for increased risk at exposures >10 versus ≤5 µg/m³. In subgroup analyses, positive associations were observed among females, with larger effect estimates at exposure >10 µg/m³, whereas associations remained null among males. No differences were observed across APOE genotypes or age groups. DISCUSSION: Findings suggest a threshold of >10 µg/m³ and heightened susceptibility in females. Further research in low-exposure settings is warranted.

doi.org/10.1002/alz.71256Open accessPubMed 41778877Populations