Long-Term Exposure to PM10 and in vivo Alzheimer's Disease Pathologies

Background: Previous studies indicated an association between Alzheimer's disease (AD) dementia and air particulate matter (PM) with aerodynamic diameter <10 mu m (PM10), as well as smaller PM. Limited information, however, is available for the neuropathological links underlying such association. Objective: This study aimed to investigate the relationship between long-term PM10 exposure and in vivo pathologies of AD using multimodal neuroimaging. Methods: The study population consisted of 309 older adults without dementia (191 cognitively normal and 118 mild cognitive impairment individuals), who lived in Republic of Korea. Participants underwent comprehensive clinical assessments, C-11-Pittsburg compound B (PiB) positron emission tomography (PET), and magnetic resonance imaging scans. A subset of 78 participants also underwent F-18-AV-1451 tau PET evaluation. The mean concentration of PM with aerodynamic diameter <10 mu m over the past 5 years (PM10(mean)) collected from air pollution surveillance stations were matched to each participant's residence. Results: In this non-demented study population, of which 62% were cognitively normal and 38% were in mild cognitive impairment state, exposure to the highest tertile of PM10(mean) was associated with increased risk of amyloid-beta (A beta) positivity (odds ratio 2.19, 95% confidence interval 1.13 to 4.26) even after controlling all potential confounders. In contrast, there was no significant associations between PM10(mean )exposure and tau accumulation. AD signature cortical thickness and white matter hyperintensity volume were also not associated with PM10(mean) exposure. Conclusion: The findings suggest that long-term exposure to PM10 may contribute to pathological A beta deposition.