Traffic pollution is associated with an increased risk of dementia
A meta-analysis reviewed 17 studies that looked at traffic-related air pollution.
According to a meta-analysis recently published in Neurologymedical journal American Academy of Neurology, higher exposure to a certain type of traffic-related air pollution known as particulate matter may be associated with an increased risk of dementia. The researchers focused on fine particulate matter, or PM2.5, which consists of airborne pollutants less than 2.5 microns in diameter. A meta-analysis examined all available studies on the relationship between air pollution and dementia risk.
“As people continue to live longer, conditions like dementia are becoming more common, so discovering and understanding preventable risk factors is critical to reducing the rise of this disease,” said study author Ehsan Abolhasani, MD, PhD. Western University in London, Canada. “Since a World Health Organization report found that more than 90% of the world’s population lives in areas with higher than recommended levels of air pollution, our results provide more evidence to enforce air quality regulations and accelerate the transition away from fossil fuels. sustainable energies.”
The researchers analyzed 17 studies for the meta-analysis. Participants were at least 40 years old. More than 91 million people participated in all studies. Of them, 5.5 million or 6% developed dementia.
The studies took into account age, gender, smoking, level of education and other variables that may increase or decrease the risk of dementia.
The researchers analyzed air pollution exposure rates for those with and without dementia and found that those without dementia had lower average daily exposure to fine particulate air pollutants. The US Environmental Protection Agency (EPA) considers an average annual exposure of up to 12 µg/m3 to be safe.
The researchers found that the risk of dementia increased by 3% for every microgram per cubic meter (µg/m3) increase in fine particulate matter exposure.
“Although our meta-analysis does not prove that air pollution causes dementia, it only shows an association, we hope these findings empower people to take an active role in reducing their exposure to pollution,” Abolhasani said. “By understanding the risk of dementia from 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 found no significantly increased risk when these other classes of pollutants were considered alone.
A limitation of the meta-analysis was the small number of available studies on this specific topic. Abolhasani said more studies are needed.
Reference: “Air Pollution and Incidence of Dementia: A Systematic Review and Meta-Analysis” by Ehsan Abolhasani, Vladimir Hachinski, Nargess Ghazaleh, Mahmoud Reza Azarpazhooh, Naghmeh Mokhbera, and Janet Martin, October 26, 2022. Neurology.