Reducing pollution and improving air quality reduces people’s risk of developing Alzheimer's disease and other forms of dementia, new studies have shown.
Previous research had suggested a link between exposure to pollution and developing Alzheimer's disease-related brain plaques.
But new research reported at the Alzheimer's Association International Conference in Denver shows a clear link between reduced risk of dementia and reducing pollution.
The study found that reducing exposure to traffic pollutants and fine particles released by burning fuel by 10% of America’s Environmental Protection Agency's (EPA) current standard over 10 years was associated with 14% and 26% reductions in dementia risk in older women.
Other studies showed a 15% reduction in the risk of dementia in French people after a reduction in fine particles released by burning fuel.
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Alzheimer's Association director of scientific programs and outreach Claire Sexton said: "We've known for some time that air pollution is bad for our brains and overall health, including a connection to amyloid buildup in the brain.
"But what's exciting is we're now seeing data showing that improving air quality may actually reduce the risk of dementia.
“These data demonstrate the importance of policies and action by federal and local governments, and businesses, that address reducing air pollutants."
Xinhui Wang, assistant professor of research neurology at University of Southern California, looked at a group of older women (aged 74-92) who did not have dementia at the beginning of the study.
Participants were followed from 2008-2018 and detailed cognitive function tests were done every year to determine whether they developed dementia.
Participants' home addresses were noted and mathematical models were used to estimate the air pollution levels at these locations over time.
For those living in locations with greater reduction in pollutants, their risk of dementia decreased by 14% and 26%. This was similar to the lower level of risk seen in women two to three years younger.
Wang said: "Our findings are important because they strengthen the evidence that high levels of outdoor air pollution in later life harm our brains, and also provide new evidence that by improving air quality we may be able to significantly reduce risk of cognitive decline and dementia.
"The possible benefits found in our studies extended across a variety of cognitive abilities, suggesting a positive impact on multiple underlying brain regions."
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