Pollution, traffic are damaging the brain

Those living next to major roads at risk of dementia

Prolonged exposure to high levels of air pollution, usually during commute on heavily-congested roads or living close to major roads, affects the white matter within the human brain and could lead to early onset of dementia or ageing of the brain, medical experts have revealed.

Dr Hari Kishan B., a senior general physician from the city, said many studies had found a link between pollution and dementia. “Increasing levels of pollution and continued exposure to noise and contaminants increases risk of dementia,” he said.

Exposure to 2 mcg (micrograms) per cubic metre of fine-particulate matter has been associated with a 0.32 per cent reduction of brain volume. While this may not seem substantial, experts say it amounts to the equivalent of one additional year of brain ageing. Individuals exposed to 4 mcg per cubic metre of fine-particulate matter therefore, would experience two years of accelerated brain ageing.

Dr Muralidhar Reddy, a consultant neurologist, says: “Constant and prolonged exposure to air pollution results in loss of brain volume, which is usually seen in the elderly. But various lab studies on animals have shown that air pollution contributes to substantial loss in the white matter within brains. This matter is actually an insulator for transmitting signals from the brain to various parts of the body. Its loss leads to cognitive and behavioural problems in humans.”

Air pollution also exposes people to something called reactive oxygen species (ROS), which during times of environmental stress (when there are high levels of particulate matter in the air) increases dramatically and can cause significant damage to the brain. Reactive oxygen cumulatively leads to ‘oxidative stress’, which contributes to cognitive impairment and even strokes.

However, little is being done to curb air and noise pollution in India’s cities despite repeated warnings from pollution control boards, experts and the medical fraternity nationwide.

Individuals can take precautions such as wearing masks, avoiding high traffic areas if they can during daily commute.