Higher dementia risks linked to prolonged air pollution exposure
Image credit: reuters
People that suffer from heart conditions and live in areas with even minimal air pollution are at increased risk of dementia, a study suggests.
The number of people living with dementia is projected to triple in the next 30 years and no curative treatment has been identified thus far.
Recent studies have linked both cardiovascular disease and air pollution to the development of dementia, but findings on the air pollution link have been scarce and inconsistent.
A research team at Karolinska Institutet, Sweden, examined the air pollution in a study that assessed almost 3,000 adults with an average age of 74 and living in the Kungsholmen district in central Stockholm.
They were followed for up to 11 years and of the people studied, 364 developed dementia. The annual average level of particulate matter 2.5 microns or less in width (PM2.5) are considered low compared to international standards.
“Interestingly, we were able to establish harmful effects on human health at levels below current air pollution standards,” said first author Giulia Grande.
“Our findings suggest air pollution does play a role in the development of dementia and mainly through the intermediate step of cardiovascular disease and especially stroke.”
For the last five years of exposure, the risk of dementia increased by more than 50 per cent per interquartile range (IQR) difference in mean PM2.5 levels and by 14 per cent per IQR in nitrogen oxide.
Earlier exposures seemed less important. Heart failure and ischemic heart disease both enhanced the dementia risk and stroke explained almost 50 per cent of air pollution-related dementia cases, according to the researchers.
“Air pollution is an established risk factor for cardiovascular health and because CVD accelerates cognitive decline, we believe exposure to air pollution might negatively affect cognition indirectly,” Grande said.
“In our study, virtually all of the association of air pollution with dementia seemed to be through the presence or the development of CVD, adding more reason to reduce emissions and optimise treatment of concurrent CVD and related risk factors, particularly for people living in the most polluted areas of our cities.”
Earlier this month researchers presented an artificial intelligence system that can predict air pollution levels hours in advance.
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