Differential associations of PM_2.5 and particulate manganese with blood-based amyloid and tau biomarkers in cognitively unimpaired older adults.

Authors

Jiyoon Yeom, Hyunji Park, Heeseon Jang, Young Noh, Sang-Baek Koh, Jung Il Lee, Ho Hyun Kim, Sun-Young Kim, Changsoo Kim, Jaelim Cho

Published in

Environmental pollution (Barking, Essex : 1987). Pages 129304. Oct 07, 2026. Epub Oct 07, 2026.

Abstract

There are mixed findings on the associations of particulate matter (PM) with amyloid beta (Aβ) and phosphorylated tau (pTau) proteins, key pathologies of Alzheimer's disease (AD). The associations of airborne manganese (Mn) with AD biomarkers remain underexplored. We investigated the associations of PM with diameters ≤10 μm (PM₁₀) and ≤2.5 μm (PM_2.5) and their Mn constituents (Mn₁₀, Mn_2.5) with AD biomarkers. We included 340 cognitively unimpaired adults. Air pollution exposure was assessed using PM sampling and spatial modeling. Plasma Aβ40, Aβ42, pTau-181, and their ratios were measured using highly sensitive assays. Associations between air pollution exposure and the AD biomarkers were evaluated using single- and two-pollutant linear regression models per interquartile-range increase, with stratified analyses assessing potential effect modification. PM_2.5 was inversely associated with the Aβ42/Aβ40 ratio (β = -0.002, 95% CI = -0.004, -0.001, p = 0.001). Mn_2.5 was positively associated with pTau-181 (β = 0.387, 95% CI = 0.084, 0.691, p = 0.013) and the pTau-181/Aβ42 ratio (β = 0.057, 95% CI = 0.005, 0.108, p = 0.032). In the two-pollutant model, PM_2.5 remained inversely associated with the Aβ42/Aβ40 ratio (β = -0.002, 95% CI = -0.003, -0.001, p = 0.008), and Mn_2.5 remained positively associated with pTau-181 (β = 0.400, 95% CI = 0.073, 0.727, p = 0.017). Neither PM₁₀ nor Mn₁₀ exposure showed significant associations with any biomarker. The positive association between PM_2.5 and the pTau-181/Aβ42 ratio appeared stronger in APOE-ε4 carriers (β = 0.109, 95% CI = 0.016, 0.201, p = 0.022) than in non-carriers (β = 0.007, 95% CI = -0.046, 0.060, p = 0.804) (p for interaction = 0.054). PM_2.5 exposure was associated with the amyloid biomarker, whereas Mn_2.5 exposure was nominally associated with the tau biomarker. These findings suggest differential associations of PM_2.5 and its Mn constituent with amyloid- and tau-related biomarkers.

PMID:
42843548
Bibliographic data and abstract were imported from PubMed on 08 Oct 2026.

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