Regular exposure to air pollution, including emissions from vehicles, may increase the risk of dementia, according to a new analysis published in The Lancet Planetary Health journal recently.
The study reviewed data from 51 existing scientific studies involving over 29 million people and found a strong link between air pollutants and the development of dementia, particularly vascular dementia.
The researchers found that for every 10 micrograms per cubic metre of PM2.5 in the air, the relative risk of developing dementia increased by 17 percent.
PM2.5 refers to fine particulate matter, including soot, which is often released from car exhaust and the burning of wood. The analysis also revealed that for every 1 microgram per cubic metre of soot, the risk of dementia increased by 13 percent.
Dementia, including Alzheimer’s disease, currently affects an estimated 57.4 million people globally. This number is expected to rise sharply, reaching 152.8 million by the year 2050.
The researchers believe that air pollution may contribute to dementia by causing inflammation in the brain and oxidative stress, which can damage cells, proteins, and DNA, leading to cognitive decline.
Most of the studies included in the meta-analysis came from high-income countries. Out of the 34 papers analysed in detail, 15 were from North America, 10 from Europe, seven from Asia, and two from Australia.
The analysis found a statistically significant connection between air pollutants such as PM2.5, nitrogen dioxide (NO2), and soot and the occurrence of dementia.
The impact of these pollutants was found to be particularly strong in cases of vascular dementia, a condition caused by reduced blood flow to the brain.
The researchers have emphasised the need for action across multiple sectors, including health care, urban planning, and environmental regulation, to address the growing burden of dementia linked to air pollution.
