A recent meta-analysis suggests that breathing in air pollution from traffic, specifically a type called PM2.5, may be linked to a higher risk of developing dementia. P
M2.5 refers to very tiny particles—less than 2.5 microns in diameter—that are suspended in the air and often come from car exhaust and burning fossil fuels.
These particles are so small they can go deep into our lungs and even enter our bloodstream.
This research, published in Neurology® on October 26, 2022, reviewed all available studies on air pollution and dementia. It included data from 17 studies and more than 91 million people aged over 40. Among them, around 5.5 million people (6%) were diagnosed with dementia during the study period.
One of the key findings was that people who did not develop dementia were exposed to lower average levels of PM2.5 than those who did. After adjusting for other risk factors such as age, gender, smoking, and education, researchers found that for every increase of just 1 microgram per cubic meter (µg/m3) of PM2.5 in the air, the risk of dementia rose by 3%.
While this study does not prove that air pollution directly causes dementia, it shows a strong link. Most of the world’s population—more than 90%—lives in areas where air pollution levels exceed safe limits recommended by the World Health Organization.
Lead researcher Dr. Ehsan Abolhasani of Western University in Canada emphasized that as the population ages and dementia becomes more common, identifying preventable risks like air pollution becomes increasingly important. The results support stronger air quality regulations and efforts to reduce fossil fuel emissions.
Although the study focused mainly on PM2.5, it also looked at other pollutants like nitrogen dioxide, nitrogen oxides, and ozone. However, these other pollutants did not show a clear connection to dementia risk when studied on their own.
One limitation of the meta-analysis is that there aren’t yet many studies on this exact topic, so more research is needed to better understand how air pollution affects brain health. Still, these findings can help guide people and policymakers to take action—like promoting clean energy, reducing traffic emissions, and choosing to live in areas with cleaner air.
Reducing air pollution not only benefits our lungs and heart but may also protect our brains in the long run.
If you care about dementia, please read studies about Early heart rhythm problem linked to higher dementia risk and findings of Green leafy vegetables may help reduce Alzheimer’s risk.
For more about dementia, please read studies about Research shows an important cause of frontotemporal dementia and findings of New way to detect Lewy body disease early, a leading cause of dementia.
The study is published in Neurology.
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