Emerging research suggests that air pollution, particularly from traffic-related fine particulate matter, could be a substantial cause of severe forms of dementia, irrespective of genetic predisposition. A study conducted in Atlanta, Georgia, reveals a concerning association between higher exposure to traffic-related air pollution and the presence of amyloid plaques linked to Alzheimer’s disease in the brain.
The investigation, led by researchers from Atlanta’s Emory University, focused on the impact of fine particulate matter known as PM2.5, with particles smaller than 2.5 microns in diameter. These particles, penetrating deep into living tissue, including the brain, have been identified as a significant component of ambient pollution in urban areas worldwide, raising concerns for residents, especially those living near busy roads.
Analyzing brain tissue from 224 individuals, 90% of whom had dementia, the study assessed traffic-related PM2.5 exposure in the years leading up to their deaths. Results showed a clear correlation between high PM2.5 exposure and elevated levels of amyloid plaques in the brain.
Anke Huels, lead author and assistant professor at Emory University, highlighted the findings, stating, “Donors living in areas with high concentrations of traffic-related air pollution, especially PM2.5 exposure, exhibited higher levels of Alzheimer’s disease neuropathology in their brains.” The study revealed that a 1 µg/m3 higher PM2.5 exposure in the year before death nearly doubled the likelihood of elevated amyloid plaques, with an 87% higher likelihood for those with higher exposure in the three years before death.
Interestingly, the research also explored the impact of the ApoE4 gene variant, associated with Alzheimer’s disease. The study found that the link between air pollution and Alzheimer’s severity was more pronounced in individuals without the ApoE4 allele, suggesting that environmental factors like air pollution may contribute to Alzheimer’s risk in those not genetically predisposed.
Published in the online issue of Neurology®, the medical journal of the American Academy of Neurology on February 21, 2024, these findings shed light on the concerning connection between air pollution and dementia, emphasizing the potential risks for individuals living in urban areas, particularly near high-traffic zones.
