Per the research, people with higher exposure to traffic-related fine particulate matter were ‘more likely’ to have high amounts of amyloid plaques in their brains that are associated with Alzheimer’s.

Air pollution is a health hazard. Breathing polluted air can not only affect your lungs, it can also damage the rest of the organs, including the brain and the heart. Citing research carried out in Atlanta, Georgia and published in the online issue of ‘Neurology‘, a Guardian report stated that air pollution from traffic is linked to some of the ‘more severe forms of dementia’, and could be a ‘significant cause’ of the condition in people who are not even genetically predisposed to it. Dementia refers to a group of degenerative mental diseases in which there is loss of cognitive function that goes beyond normal ageing. Symptoms include confusion, mood-swings, long-term memory loss and a gradual loss of bodily functions. Alzheimer’s is the most common form of dementia, caused due to plaque deposition in the brain’s neurons, which affects its functioning.

Traffic-Related Fine Particulate Matter

Per the research, people with higher exposure to traffic-related fine particulate matter were ‘more likely’ to have high amounts of amyloid plaques in their brains that are, as mentioned earlier, associated with Alzheimer’s. This is alarming, especially for people living in big global cities where pollution levels are high. According to the Guardian report, team of researchers from Atlanta’s Emory University wanted to investigate the impact on the brain when it is exposed to the type of fine particulate matter known as PM2.5, which comprises particles of ‘less than 2.5 microns in diameter’, or ‘about a hundredth the thickness of a human hair’. When suspended in the air, it is known to penetrate deep into the tissue, including crossing the ‘blood-brain barrier’.

The findings stated that traffic-related PM2.5 concentrations are a ‘major source of ambient pollution in the metro-Atlanta area’, and also in urban centres across the planet.

How The Research Was Conducted

Brain tissues of 224 people from Atlanta were examined, 90 per cent of whom had a diagnosis of some form of dementia. They had also agreed to donate their brains to science. Researchers also analysed the traffic-related PM2.5 pollution exposure at the subjects’ homes in the years leading up to their deaths.

Anke Huels, assistant professor at Emory University in Atlanta and lead author on the study was quoted as saying: “We found that donors who lived in areas with high concentrations of traffic-related air pollution exposure, in particular PM2.5 exposure, had higher levels of Alzheimer’s disease neuropathology in their brain. In particular, we looked at a score that is used to evaluate amyloid plaques in the brain, in autopsy samples…” It was shown that donors who live in areas with higher levels of air pollution had higher levels of amyloid plaques in their brain.

Gene Variant Associated With Alzheimer’s Disease

Researchers also investigated whether ApoE4 — the main gene variant associated with Alzheimer’s disease — had any influence on the ‘relationship between air pollution and signs of Alzheimer’s’. “We found that the association between air pollution and severity of Alzheimer’s disease was stronger among those who did not carry an ApoE4 allele, those who did not have that strong genetic risk for Alzheimer disease. Which kind of suggests that environmental exposures like air pollution may explain some of the Alzheimer’s risk in people whose risk cannot be explained by genetic risk factor,” Huels was quoted as saying.