A new international study, published in The Lancet Planetary Healthstrengthens growing concerns about the effects of air pollution on cognitive health. Led by a team of researchers from the epidemiology unit of Cambridge Universitythis research highlights the link between prolonged exposure to certain pollutants and a significant increase in the risk of dementia.
A pathology in high increase in global
Nearly 60 million people are currently affected by dementiaa figure that could reach 152.8 million by 2050according to projections from a 2022 study. This neurodegenerative syndrome, which gradually alters memory, reasoning and communication capacities, is already the eighth cause of mortality in the world. Faced with this alarming trend, scientists seek to better understand the modifiable risk factors.
Well identified pollutants
The study is based on the cross -analysis of around fifty research carried out in North Americain Europein Asia and in Australia. It highlights three main pollutants associated with an increase in the risk of dementia: fine particles (PM2.5), Nitrogen dioxide (no₂) et to suie.
PM2.5, the diameter of which is less than 2,5 micronsmainly come from thermal vehicles, the combustion of domestic wood and industrial emissions. According to the study, Each increase of 10 micrograms per cubic meter of PM2.5 increases the risk of dementia by 17 %. A concentration already exceeded in several European cities, including Pariswhere the average levels have reached 10,3 µg/m³ in 2023, against a recommendation of 5 µg/m³ established by The World Health Organization (WHO).
Another worrying data: Exposure of a single microgram per cubic meter of soot would be associated with a 13 % increase in the risk of dementia.
Implications beyond the medical field
If the fight against dementia remains a public health issue, the authors of the study insist on the intersectoral dimension of prevention. For Christiaan Bredellone of the main co-authors, Decisions in terms of town planning, transport or environmental regulation policy can contribute as much as care systems to mitigate the impact of pollution on the human brain.
The results of the study therefore argue for A tightening of air quality standardsin the name of better prevention of cognitive diseases. Researchers believe that a reduction in exposure to these pollutants could result in major profits in terms of public health, medical expenses and quality of life.
An alert for global public policies
This research is added to an increasing series of studies highlighting the effects of air pollution on biological functions far beyond the lungs. It also recalls that the sanitary challenges linked to pollution do not only concern respiratory or cardiovascular diseases, but also affect brain functions, including in aging societies.
While several countries are already committed to plans to reduce polluting emissions, this new scientific lighting could speed up reforms. Local and international, the protection of cognitive health could become a central argument to rethink urban development and energy transition.
