Air pollution 'significant contributor to dementia'

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A man walks in the Sanlitun shopping district on a polluted day, in Beijing, China, November 6, 2021. —Reuters
A man walks in the Sanlitun shopping district on a polluted day, in Beijing, China, November 6, 2021. —Reuters

Air pollution, particularly from traffic-related fine particulate matter, has been identified as a potentially major factor contributing to severe forms of dementia, according to recent research conducted in Atlanta, Georgia, The Guardian reported. 

The study suggests that exposure to traffic-related air pollution may be a significant cause of dementia, even among individuals not genetically predisposed to the condition.

The research, led by a team from Emory University in Atlanta, focused on the effects of fine particulate matter known as PM2.5, which consists of particles less than 2.5 microns in diameter. 

This type of pollution, prevalent near busy roads, has been linked to the presence of amyloid plaques in the brain, a characteristic associated with Alzheimer's disease. 

The study examined brain tissue from 224 individuals, 90% of whom had a dementia diagnosis, with a particular emphasis on those living in areas with high concentrations of traffic-related air pollution.

The results revealed a positive correlation between exposure to high levels of PM2.5 and the presence of amyloid plaques in the brains of the subjects. 

Individuals with increased PM2.5 exposure were nearly twice as likely to have higher levels of plaques in the year before death, while those with elevated exposure in the three years prior were 87% more likely to exhibit higher plaque levels. 

Importantly, the study also found that the association between air pollution and Alzheimer's severity was stronger in individuals without the ApoE4 gene variant, suggesting that environmental factors, such as air pollution, may play a role in Alzheimer's risk, especially in those without a strong genetic predisposition.

The findings, shedding light on the potential health risks posed by air pollution, were published in the 21 February 2024 online issue of Neurology®, the medical journal of the American Academy of Neurology.