New research suggests that air pollution could significantly contribute to the progression of Alzheimer’s disease and other forms of dementia. A team from the Perelman School of Medicine at the University of Pennsylvania has published findings indicating that exposure to air contaminants may hasten the accumulation of harmful proteins in the brain, thereby intensifying cognitive decline in affected individuals.
The study, which appeared in JAMA Neurology, focused on how fine particulate matter (PM2.5) correlates with brain alterations associated with dementia and Alzheimer’s, as well as the severity of related symptoms. Over the course of 23 years, researchers examined the brains of 602 individuals posthumously at the Penn Medicine Brain Bank, collecting data from 1999 to 2022. This analysis was conducted between January and June 2025, involving both patients diagnosed with common forms of dementia and movement disorders, as well as older adults without cognitive impairments.
To evaluate the subjects’ exposure to air pollution, researchers analyzed their residential locations before death or prior to their last cognitive assessment. It was determined that those living in areas with higher pollution exhibited more pronounced Alzheimer’s-related changes in their brain tissue.
The correlation was striking: each incremental rise in PM2.5 exposure was linked to a 19% increase in the likelihood of experiencing more severe forms of Alzheimer’s disease. Within a subset of 287 participants who underwent assessments for dementia before passing away, higher levels of PM2.5 exposure were associated with escalated cognitive and functional deterioration. This deterioration included significant memory loss, impaired judgment, and challenges related to personal care and communication abilities.
About 63% of the relationship between air pollution and the severity of dementia was attributable to Alzheimer’s-related brain changes. Dr. Edward Lee, M.D., Ph.D., co-director of Penn’s Institute on Aging, emphasized the implications of these findings in a recent press release. “This study shows that air pollution doesn’t just increase the risk of dementia — it actually makes Alzheimer’s disease worse,” Lee remarked, underscoring the importance of understanding various environmental factors in the quest for new treatments.
Lee noted that while air pollution levels in the U.S. are currently at their lowest in decades, even a single year of living in a high-pollutant environment can significantly elevate one’s risk of developing Alzheimer’s disease.
However, the study is not without its caveats. The subjects primarily represented a demographic profile that was predominantly White and well-educated, hailing from more affluent neighborhoods. Consequently, the findings may not accurately reflect broader experiences with different types of dementia or among diverse populations. Researchers acknowledged that they may have also underestimated pollution’s effects on cerebral blood vessels, a critical area of concern in cognitive decline.
This investigation was backed by funding from esteemed organizations including the National Institutes of Health and the National Institute of Environmental Health Sciences. As the research moves forward, it remains crucial to dissect the interplay between environmental factors and neurodegenerative diseases, guiding future strategies in prevention and treatment both on individual and societal levels.
