According to a new study, people most exposed to fine particles from air pollution are more at risk of developing dementia than those least affected.
- Air pollution is responsible for around 7 million deaths on average per year, according to a WHO study. Including 48,000 in France. Exhaust gases related to road traffic are the primary cause of fine and ultrafine particle emissions.
- The impact of air pollution on health is even greater in children, whose nervous system is still developing, and therefore more sensitive and vulnerable to stale air than that of adults.
- In France, it is estimated that 1.2 million people suffer from Alzheimer’s disease and other forms of dementia.
Each year, around 48,000 people die prematurely from the consequences of air pollution, according to Santé Publique France. Breathing air stale by pollutants does not only affect the respiratory capacities or the good cardiovascular function. It would also be directly harmful to the health of our brain by increasing the risk of cognitive decline (dementia, Alzheimer’s disease, etc.), according to a recent study published in the American medical journal Neurology.
The risk of dementia increases with exposure to fine particles
Researchers at the University of Western Ontario, Canada, relied on a meta-analysis compiling the 17 available studies on the link between dementia and air pollution. A total of 91 million people, all aged at least 40, were examined, and 5.5 million of them, or 6%, developed dementia during the years of follow-up. After adjusting the participants’ data according to external factors (age, smoking, education, etc.), the scientists then compared the levels of exposure of each to the fine particles : PM2.5, airborne particles less than 2.5 microns in diameter capable of penetrating deep into the lungs and bloodstream.
Result: people who did not develop dementia were also those who were least exposed to air pollutants, for example by living far from road traffic areas, the first responsible for fine particle emissions. In detail, the study reveals that the risk of dementia increased by 3% for each increase of one microgram per cubic meter of exposure to PM2.5, knowing that the recommendations of the World Health Organization (WHO) set an annual safe threshold at 5 µg/m3 (compared to 12 µg/m3 by the American authorities).
90% of the population is overexposed to air pollution
“Although our meta-analysis does not prove that air pollution causes dementia, it does show an association […] 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 less polluted areas, and advocating for a reduction of road pollution in residential areas”said neuroscientist Ehsan Abolhasani, lead author of the study, in a communicated.
While a recent WHO report showed that more than 90% of the world’s population lives in areas with air pollution levels above guidelines, the researcher concludes by making the case for action at the policy level . “Our results provide more evidence for enforcing air quality regulations and accelerating the transition from fossil fuels to sustainable energy.”
