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According to a new large -scale study, breathing regularly polluted air could increase the risk of dementia over time.
Analysis, published in the revue The Lancet Planetary Healthis the largest study to date to confirm the link between air pollution and brain health, even if questions remain regarding the real mechanism and the period during which individuals are most at risk.
About 57 million people worldwide are suffering from dementia, which occurs when connections of nerve cells in the brain are lost or damaged.
Scientists have identified Some risk factorswhose air pollution, but so far, they did not know what pollutants presented the most risks.
“A serious and growing threat to the health of our brain”
For this new analysis, researchers from the University of Cambridge, in the United Kingdom, have examined the data of 51 reports relating to nearly 30 million people, mainly in high-income countries.
They found close ties between the risks of dementia and Exposure to fine particles Coming from sources such as car emissions, power plants and dust, as well as nitrogen dioxide from fuel combustion and soot from cars exhaust gases and wood combustion.
These pollutants seem to have narrower links with vascular dementia – which is caused by a decrease in blood circulation in the brain – with Alzheimer’s disease, the most common form of dementia, but these differences may not be significant.
“Air pollution is not only an environmental problem, it is a serious and growing threat to the health of our brain”said in a press release Dr Isode Radford, principal responsible for research policy on Alzheimer’s disease in the United Kingdom.
Scientists still do not know if air pollution is really behind dementia, but they think that pollution can cause inflammation and oxidative stress – which can damage cells and DNA – in the brain, two phenomena that have been associated with the appearance and progression of dementia.
“The organization has no effective defense against ultrafine particle cocktails that we produce outside, especially because of traffic, and inside, for example by heating our homes using stoves”explains Barbara Maher, professor of environmental magnetism at the University of Lancaster, in the United Kingdom, who did not participate in the study.
“There remains a lot to do to tackle this invisible threat”
However, the analysis presents certain limits. It is notoriously difficult to know exactly what pollutants an individual is exposed over time, how these pollutants interact with each other and how they affect human health.
This study, like many others, estimated the exposure of people to air pollution based on the address of their home. It is not known either at what period of life this exhibition is most important, but researchers think that it could extend over several years, even several decades.
“A better approach [de la recherche] is cruelly necessary “said in a press release from Dr. Tom Russ, specialist in dementia and researcher in old age psychiatry at the University of Edinburgh.
“This article studies better than previous work The link between air pollution and dementia, but we still need better research to clarify how and why air pollution can be bad for the brain”adds Tom Russ, who did not participate in the study.
Scientists and dementia combat associations call on governments to adopt more strict air quality rules and to take other measures to reduce the exposure of the population to air pollution.
“There is still a lot to do to tackle this invisible threat”says Isode Radford.
