A new research has confirmed a strong link between long-term exposure to air pollution and an increased risk of developing dementia. The study revealed a statistically significant association between dementia and exposure to three key air pollutants: PM2.5 (fine particulate matter), nitrogen dioxide, and soot.
Published in The Lancet Planetary Health, the systematic review analysed 51 studies involving over 29 million participants worldwide who had been exposed to air pollutants for at least one year. Researchers at the Medical Research Council’s epidemiology unit at the University of Cambridge led the study.
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Of the three air pollutants, PM2.5, emitted by vehicle exhausts, power plants, and wood-burning stoves, showed the strongest link. For every 10 micrograms per cubic metre increase in PM2.5 levels, the relative risk of developing dementia rose by 17%. Exposure to soot resulted in a 13% increased risk. Nitrogen dioxide, commonly produced from burning fossil fuels, was also linked to elevated dementia risk.
The biological mechanism behind this link is thought to involve brain inflammation and oxidative stress, a damaging chemical process that can impair cells, proteins, and DNA.
“This study provides further evidence that long-term exposure to outdoor air pollution is a clear risk factor for dementia onset in otherwise healthy adults,” said Dr. Haneen Khreis, the study’s senior author. “Reducing air pollution can offer enormous health, social, climate, and economic benefits.”
While dementia already affects an estimated 57 million people worldwide, that number is expected to rise to 150 million by 2050.
