Research indicates that air pollution from vehicles is associated with more serious types of dementia and may be a major contributor to the development of the disease in individuals who are not genetically susceptible to it.

A study conducted in Atlanta, Georgia discovered a correlation between increased exposure to air pollution from traffic-related fine particulate matter and higher levels of amyloid plaques in the brain, which have been linked to Alzheimer’s disease.

The results, which may cause concern for residents of towns and cities, especially those living close to busy roads, contribute to the negative effects already associated with pollution from road traffic. These effects can range from climate change to respiratory illnesses.

A group of scientists from Emory University in Atlanta aimed to examine the impact of PM2.5, a type of fine particulate matter, on the human brain.

This substance is made up of particles that are smaller than 2.5 microns in size, which is approximately one hundredth the width of a human hair. It is present in the air and can enter living tissue, even crossing the protective barrier of the brain. In the metro-Atlanta region and other urban areas worldwide, PM2.5 levels from traffic are a significant contributor to overall air pollution.

The scientists at Emory University studied the brain samples of 224 individuals in Atlanta, where 90% had been diagnosed with a type of dementia. These individuals had previously agreed to donate their brains for medical research upon their passing. The researchers also analyzed the levels of PM2.5 pollution from traffic near the participants’ homes in the years before their deaths.

3).

The typical level of exposure in the year prior to death was 1.32 micrograms per cubic meter.³) and 1.35 µg/m³

During the three years prior to passing away.

According to the study’s lead author, Anke Huels, an assistant professor at Emory University in Atlanta, individuals who donated and resided in regions with elevated levels of air pollution from traffic, specifically PM2.5 exposure, displayed increased levels of Alzheimer’s disease pathology in their brain.

Specifically, we examined a measure utilized to assess amyloid plaques in the brain from autopsy samples. Our findings revealed a correlation between individuals residing in regions with elevated air pollution and increased levels of both amyloid plaques in the brain.

3 increase in PM2.5 exposure had a 10% higher level of amyloid plaques.

The team discovered that individuals who were exposed to high levels of PM2.5 had a direct correlation to increased levels of amyloid plaques in their brains. They observed that for every 1 µg/m3 increase in PM2.5 exposure, there was a corresponding 10% increase in the level of amyloid plaques.³

Individuals with increased exposure to PM2.5 in the year preceding their death had a nearly two-fold higher probability of having elevated levels of amyloid plaques in their brains. Similarly, those with greater exposure in the three years prior to their death had an 87% increased likelihood of having elevated plaque levels.

Huels and her team examined the impact of the primary gene variation linked to Alzheimer’s disease, ApoE4, on the connection between air pollution and signs of Alzheimer’s in the brain.

According to Huels, our research discovered a stronger connection between air pollution and the severity of Alzheimer’s disease in individuals who do not have the ApoE4 allele, indicating that environmental factors such as air pollution may play a role in the development of Alzheimer’s disease in individuals who do not have a strong genetic predisposition.

The results were released in the February 21, 2024 online edition of Neurology®, the medical publication of the American Academy of Neurology.

Source: theguardian.com