PM2.5 Exposure Linked to Increased Dementia Severity

MONDAY, Sept. 22, 2025 (HealthDay News) — Exposure to fine particulate matter air pollution (PM_2.5) is associated with increased dementia severity as well as Alzheimer disease neuropathologic change (ADNC), according to a study published online Sept. 8 in JAMA Neurology.

Boram Kim, M.D., from the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, and colleagues used data associated with autopsy cases collected from 1999 to 2022 at the Center for Neurodegenerative Disease Research Brain Bank at the University of Pennsylvania to examine associations between PM_2.5 exposure, dementia severity, and dementia-associated neuropathologic change. Data were included for 602 autopsy cases with common forms of dementia and/or movement disorders and older controls.

The researchers found that the odds of more severe ADNC were increased in association with higher PM_2.5 exposure prior to death (odds ratio, 1.19; 95 percent confidence interval, 1.11 to 1.28). In a subset of 287 cases with Clinical Dementia Rating Sum of Boxes (CDR-SB) assessment records, greater cognitive and functional impairment was seen in association with higher PM_2.5 exposure prior to CDR-SB assessment (β = 0.48). ADNC mediated 63 percent of the association between higher PM_2.5 exposure and greater cognitive and functional impairment (β = 0.30).

“This study shows that air pollution doesn”t just increase the risk of dementia — it actually makes Alzheimer disease worse,” coauthor Edward B. Lee, M.D., Ph.D., also from the Perelman School of Medicine, said in a statement. “As researchers continue to search for new treatments, it”s important to uncover all of the factors that contribute to the disease, including the influence of the environment in which they live.”

Several authors disclosed ties to the biopharmaceutical industry.

Abstract/Full Text (subscription or payment may be required)