Living in areas with poor air quality could make Alzheimer’s disease progress faster, according to new research from the Perelman School of Medicine at the University of Pennsylvania.
The study is the first to link air pollution directly with the buildup of amyloid plaques and tau tangles the toxic proteins that define Alzheimer’s disease using post-mortem brain tissue.
Both plaques and tangles are considered hallmarks of Alzheimer’s disease. While amyloid plaques disrupt communication between cells, tau tangles cripple the function within cells. Together, they progressively destroy brain networks, leading to memory loss, confusion, difficulty with language and other symptoms of dementia.
Researchers examined more than 600 brain donations from Penn Medicine’s Brain Bank. They compared medical records with satellite and air monitoring data to calculate each person’s exposure to PM2.5, in the year before death.
They found that for every 1 µg/m³ increase in PM2.5, the risk of worse Alzheimer’s pathology rose by 19%. People who had lived in areas with higher pollution not only had more extensive amyloid and tau buildup, but also showed faster cognitive and functional decline. Symptoms included memory loss, impaired judgment, difficulties with speech and trouble managing personal care.
Edward Lee, MD, PhD, co-director of Penn’s Institute on Aging said: ‘This study shows that air pollution doesn’t just increase the risk of dementia—it actually makes Alzheimer’s disease worse. 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.’
While earlier studies had linked pollution with a higher risk of dementia – we reported on this research last week – these findings show a direct connection between PM2.5 exposure and brain pathology. The findings also suggest that much of the impact of pollution on cognition is mediated by these biological changes.
With dementia already affecting more than 55 million people worldwide, researchers say the findings underscore the need to view air quality as a public health issue. Cleaner air could help not only prevent Alzheimer’s in the first place but also slow its progression.
Lee added: ‘In the United States, air pollution is at the lowest levels in decades, but even just a year living in an area with high levels of pollution can have a big impact on a person’s risk for developing Alzheimer’s disease. It underscores the value of environmental justice efforts that focus on reducing air pollution to improve public health.’
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