New findings suggests that pollution may trigger harmful brain changes that increase the risk of developing the disease.
One of the most common dementia types
Lewy body dementia affects more than one million people in the United States and occurs in two forms: dementia with Lewy bodies and Parkinson’s disease dementia.
Both arise when the protein alpha-synuclein builds up and destroys brain cells.
Air pollution as a catalyst
Researchers discovered that fine particulate matter (PM2.5) can alter alpha-synuclein into a new, more harmful strain, closely resembling the one found in patients with Lewy body dementia.
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Alarming results from mouse studies
When mice were exposed to PM2.5, their alpha-synuclein changed in ways that drive disease processes similar to Parkinson’s dementia.
Signs of brain shrinkage and cognitive decline
After ten months of exposure, mice showed brain shrinkage, abnormal protein changes, and clear signs of memory and behavioral decline.
Protection without alpha-synuclein
Mice lacking the alpha-synuclein gene showed no brain damage despite exposure to air pollution.
This highlights that the protein is the key driver, while pollution acts as a trigger.
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Effects beyond the brain
Exposed mice also developed signs of Lewy body disease in the lungs and gut, supporting the theory that the illness may spread through multiple entry points in the body.
Humanized mice confirm the pattern
Researchers created mice with human-like mutations that make them prone to alpha-synuclein buildup with age.
These mice also developed cognitive problems after exposure to pollution.
Parallels between mice and humans
By comparing gene expression in mouse brains with human patients, scientists found strong similarities in a brain region responsible for emotion and cognition, reinforcing the pollution-dementia link.
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Large-scale data supports the connection
An analysis of 56 million U.S. hospital records revealed that higher exposure to PM2.5 was linked to a significantly increased risk of hospitalization for Lewy body dementia.
Greater risk than Parkinson’s without dementia
The study found a stronger connection between pollution and dementia-related diseases than with Parkinson’s without dementia, suggesting that air pollution particularly accelerates dementia progression.
Unanswered questions about pollutants
It is still unclear which substances in PM2.5 are responsible.
Since samples from China, the U.S., and Europe showed the same results, researchers believe a common component plays a critical role.
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Public health and prevention implications
The discovery could pave the way for targeted treatments, but it also highlights the urgent need to take air pollution seriously as a public health issue to reduce dementia risk.
This article is based on information from National Geographic.
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