New Research Suggests That Frequently Sitting In Traffic And Being Exposed To Smog Is Associated With A Higher Risk Of Amyloid Plaque Accumulation In The Brain, A Key Indicator Of Alzheimer’s Disease Pathology
If you live in or near a major metropolitan area, then you’re no stranger to traffic– whether you’re sitting bumper to bumper while commuting to work or simply trying to get your grocery shopping done.
Air pollution related to traffic is also well-known for its harmful effects on our lungs. But, a recent study published in the American Academy of Neurology has highlighted a concerning potential link between smog and dementia.
Researchers have found that individuals who are more frequently exposed to pollution from traffic may have a higher risk of accumulating amyloid plaques in their brains, a key indicator often associated with Alzheimer’s disease.
While the research stops short of claiming that air pollution directly leads to an increase in amyloid plaques, it does emphasize a notable correlation between the two.
“These results add to the evidence that fine particulate matter from traffic-related air pollution affects the amount of amyloid plaque in the brain,” said Anke Huels, the study’s author.
“More research is needed to investigate the mechanisms behind this link.”
The research team evaluated fine particulate matter– or PM 2.5– which refers to tiny pollutant particles smaller than 2.5 microns across floating in the air. They also analyzed brain tissue from 224 individuals who had consented to donate their brains post-mortem for dementia research. On average, these donors died at 76 years old.
The study honed in on exposure to air pollution related to traffic, leveraging the deceased individuals’ last known home addresses in the Atlanta area to gauge this. Traffic-derived PM2.5 particles are a significant component of air pollution in many cities, including the metropolitan Atlanta area.
The average exposure to these particles was measured at 1.32 micrograms per cubic meter (µg/m^3) in the year before death and 1.35 µg/m^3 over the three years leading up to death.
BullRun – stock.adobe.com – illustrative purposes only
Upon comparing levels of pollution exposure with indicators of Alzheimer’s disease in the brain, such as amyloid plaques and tau tangles, researchers found that individuals who had been more exposed to smog both one and three years before passing away were more likely to have a higher presence of amyloid plaques in their brains.
Individuals exposed to an additional 1 µg/m^3 of PM2.5 in the year leading up to their death were nearly twice as likely to exhibit elevated levels of amyloid plaques. Furthermore, those exposed to higher levels of PM2.5 in the three years prior to passing away were 87% more likely to present with increased plaque accumulation.
The team also made sure to evaluate whether the primary gene variant associated with Alzheimer’s disease (APOE e4) had any impact on the connection between air pollution and Alzheimer’s markers in the brain. This analysis revealed that the most significant link between air pollution and Alzheimer’s indicators was observed in individuals who did not carry the gene variant.
“This suggests that environmental factors such as air pollution could be a contributing factor to Alzheimer’s in patients in which the disease cannot be explained by genetics,” Huels explained.
As for limitations in this study, the researchers relied on the last known addresses of the participants at the time of their death to estimate air pollution exposure, which could lead to inaccuracies in classifying pollution levels. Additionally, the majority of the study’s participants were highly educated and white, indicating that the results might not extend to more diverse or different demographic groups.
To read the study’s complete findings, visit the link here.
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