Study Links Alzheimer’s Disease Risk to Long-Term Exposure to Particulate Air Pollution

   

      A study published in PLOS Medicine links Alzheimer's disease with long-term exposure to particulate pollution. The study is large, involving 27.8 million Americans. Alzheimer’s affects 57 million people globally, including 7.2 million in the U.S. over age 65. There is no known cure for it. Thus, prevention is emphasized. The study suggests that improving air quality, especially fine particulate pollution, can aid in that prevention. Environmental health researcher Yanling Deng of Emory University, Georgia, and her colleagues, examined data on more than 27.8 million U.S. Medicare recipients aged 65 years and older from 2000 to 2018.

“The data is clear enough to suggest that we need to treat air quality as a brain‑health issue, not just a lung‑health issue,” said professor Bryce Vissel of the University of New South Wales (UNSW), who was not involved in the present study, in a statement.

     The study suggests that direct effects on the brain are the main mechanism rather than common chronic conditions such as hypertension, stroke, or depression, which have also been linked to Alzheimer’s and are thought to be indirect causes compared to fine particulate pollution (PM 2.5), which is now thought to be a direct cause.    

“Dementia risk is not just about personal choices. It is also about the air we breathe and the environments we live in over decades,” added epidemiologist professor Susanne Röhr, also of UNSW, who was also not involved in the present study.

     According to Masashi Kitazawa, professor of Environmental & Occupational Health at UC Irvine:

"Remarkably, results from this study predict a possibly direct toxic mechanism of (particulate matter) to (Alzheimer's disease)," said Kitazawa, who was not involved in the study.

     Other scientists and medical professionals cautioned that correlation does not imply causation.

      The study suggested that those who have had a stroke are more likely to be affected.

"Our findings suggest that individuals with a history of stroke may be particularly vulnerable to the harmful effects of air pollution on brain health, highlighting an important intersection between environmental and vascular risk factors," the authors added.

     It is not yet clear why this is the case.

"It could be related to a previously damaged brain − from stroke − being weaker in fighting off toxins," suggested Ahmad, who is also an assistant professor at the University of Maryland School of Medicine.

     The bottom line is that fine particulate pollution contributes to Alzheimer’s both indirectly and directly, although there are certainly other factors as well.

     The researchers suggest that the direct link between Alzheimer’s disease and particulate matter likely involves the mechanisms of neuroinflammation, oxidative stress, and vascular injury.

 

 

References:

 

Study of 27.8M Americans may have revealed direct Alzheimer's cause. Maria Azzurra Volpe. Newsweek. February 17, 2026. Study of 27.8M Americans may have revealed direct Alzheimer's cause

The role of comorbidities in the associations between air pollution and Alzheimer’s disease: A national cohort study in the American Medicare population. Yanling Deng , Yang Liu, Hua Hao, Ke Xu, Qiao Zhu, Haomin Li, Tszshan Ma, and Kyle Steenland. PLOS Medicine. February 17, 2026. The role of comorbidities in the associations between air pollution and Alzheimer’s disease: A national cohort study in the American Medicare population | PLOS Medicine

Air pollution may directly increase Alzheimer's risk, study finds. Sara Moniuszko, USA TODAY. February 18, 2026. Air pollution may directly increase Alzheimer's risk, study finds

Air pollution may directly contribute to Alzheimer’s disease: Cohort study finds people with stroke may be extra susceptible to air pollution’s impact on the brain. Eureka Alert. Press Release. February 17, 2026. Air pollution may directly contribute to Alzheimer’s disease | EurekAlert!