Minneapolis: Researchers suggested that greater exposure to particulate matter, a specific kind of air pollution linked to traffic, may be associated with an increased risk of dementia. Researchers focused their attention on PM2.5, or fine particulate matter, which is made up of airborne pollutants with a diameter of less than 2.5 millimetres. The risk of dementia was examined in the meta-analysis using all relevant studies.
The findings of the study were published in the journal Neurology.
"As people continue to live longer, conditions like dementia are becoming more common, so detecting and understanding preventable risk factors is key to reducing the increase of this disease," said study author Ehsan Abolhasani, MD, MSc, of Western University in London, Canada. "Since a report by the World Health Organization showed that more than 90 per cent of the world population is living in areas with higher than recommended levels of air pollution, our results provide more evidence for enforcing regulations for air quality and accelerating the transition from fossil fuels to sustainable energies."
For the meta-analysis, researchers reviewed 17 studies. Participants were over age 40. Across all the studies there were more than 91 million people. Of those, 5.5 million people, or 6 percent, developed dementia.
The studies adjusted for several factors that affect a person's risk of dementia including age, sex, smoking, and education. Researchers compared rates of air pollution exposure for people both with and without dementia and found that people who did not develop dementia had a lower average daily exposure to fine particulate matter air pollutants than people who did have dementia. The U.S. Environmental Pollution Agency (EPA) considers average yearly exposures up to 12 ug/m3 to be safe.
Researchers found that the risk of dementia increased by 3 per cent for every one microgram per cubic meter (ug/m3) increase of fine particulate matter exposure.
"While our meta-analysis does not prove that air pollution causes dementia, it only shows an association, our hope is these findings empower people to take an active role in reducing their exposure to pollution," Abolhasani said. "By understanding the risk of dementia through exposure to air pollution, people can take steps to reduce their exposure such as using sustainable energy, choosing to live in areas with lower levels of pollution and advocating for reduced traffic pollution in residential areas." They also looked at nitrogen oxides, which form smog, nitrogen dioxide, and ozone exposure, but did not find significantly increased risk when these other classes of pollutants were considered alone. —ANI