Researchers from the University of Toronto and Public Health Ontario have found those residing in close proximity to noise and fumes from traffic are 12 per cent more likely to be diagnosed with the degenerative brain disease.
Individuals living within 50 metres of a busy road are at the most risk, as results found one in nine cases of dementia in this category is caused by traffic exposure.
Almost seven million people living in the Canadian province of Ontario were tracked for over a decade up until 2012. Findings discovered people living within 50 metres of a major street were seven per cent more likely to be diagnosed than those 300 metres away, while residents between 50 and 100 metres were four per cent more at risk, followed by a two per cent risk for those between 101 and 200 metres away.
Furthermore, those who lived within 50 metres throughout the whole duration of the research were 12 per cent more likely to develop dementia than those over 300 metres away. People at over 200 metres from a major road had no increased risks, and there were no links to other health issues like Parkinson’s.
While dementia has always been linked to genetics, this study is the largest to date to suggest environmental factors have a big impact on the illness. Scientists believe issues such as air pollution and noise can cause brain shrinkage, due to nitrogen dioxide and sooty particles from engines affecting the brain.
“With our widespread exposure to traffic and the greater tendency for people to live in cities these days, this has serious public health implications,” said study leader Dr. Hong Chen.
“Increasing population growth and urbanisation has placed many people close to heavy traffic, and with widespread exposure to traffic and growing rates of dementia, even a modest effect from near-road exposure could pose a large public health burden.”
Results were published in the Lancet medical journal.
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