Study links air pollution to higher Alzheimer's risk
By: Sara Monluszko
USA Today
..... Exposure to air pollution may directly increase a person's risk for Alzheimer's disease, according to a new study.
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In the study, published February 17 [2026] in the open-access journal PLOS Medicine, researchers found a five-year average exposure to fine particulate air pollution was associated with an increased risk of the brain disorder.
..... The study used data from more than 27.8 million U.S. Medicare recipients 65 years old and older form 2000 to 2018.
..... It looked specially at fine particulate matter called PM 2.5, which Environmental Protection Agency defines as fine particles with diameters generally 2.5 micrometers and smaller that can be inhaled, which can cause serious health problems and even enter the bloodstream.
..... Previous studies have found a connection between air pollution and Alzheimer but typically via other chronic health conditions such as hypertension, stroke and depression, Until these findings, it was unclear whether air pollution causes these chronic conditions, which then lead to dementia, or if air pollution directly affected brain health.
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"We found that long-term exposure to fine particulate air pollution was associated with a higher rise of Alzheimer's disease, largely through direct effects on the brain rather than through common chronic conditions," the authors noted in a news release.
..... The authors also found that the association between air pollution and Alzheimer's risk was slightly stronger in individuals who had experienced a stroke.
..... "Our findings suggest that individuals with a history of stroke may be particularly vulnerable to the harmful effects of air pollution on brain helaht, highlighting an important intersection between environmental and vascular risk factors," the authors said.
..... A 2025 report found up to 7.2 million Americans 65 and older are living with Alzheimer's disease, an increase of about 300,000 cases form the previous year. [2024]
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The authors hope these findings will highlight the need for air quality interventions as part of dementia prevention strategies in aging populations.