Living close to heavy traffic puts people at higher risk of dementia, according to a major new study.
Research published in medical journal The Lancet, found that people who live long-term in major cities within 50 metres of a major road were 12% more likely to be diagnosed with dementia.
Ray Copes from Public Health Ontario, Canada, a co-author of the paper, said air pollution should be factored into urban planning and building design to reduce exposure. He said: ‘The real implications are not for individual choice, but at the societal and policy level.’
The researchers said the link between traffic and dementia seemed stronger among urban residents, especially those who lived in major cities. Overall, the risk of dementia rose by 7% for people within 50 metres of a busy road, by 4% for people between 50-100 metres and by 2% between 101-200 metres, compared with people living more than 300 metres away.
It is not clear whether the increased risk results from traffic noise or pollution or whether pollution directly harms the brain. The increased risk could be a knock-on effect of respiratory and/or cardiac problems caused by traffic fumes or due to less healthy urban lifestyles.
Caroline Russell, Green Party member of the London Assembly, said: ‘Air pollution in London is a public health catastrophe that no one can avoid.’
She asked: ‘How many people in London live within 50 metres of a busy road? I urge the Mayor to expand his ultra low emission zone and speed up his bus fleet clean up to bring our exposure to air pollution down.’
The study measured the incidence of dementia and multiple sclerosis among 2.2 million people over eleven years, with another study looking at Parkinson's disease. Researchers found no link between traffic and Parkinson's disease or multiple sclerosis.