Groundbreaking new research suggests that people who live near main roads are more likely to have dementia. The discovery has raised questions about how road pollution affects health.
The decade-long Canadian study, published in The Lancet, followed 6.6 million people between 2002 and 2012.
Incredibly, there was a 7% higher risk of developing dementia among people who lived within 50 metres of a main road. The risk was 4% higher when living up to 100 metres from a main road, and 2% higher at up to 200 metres. There was no dementia risk among people who lived more than 200 metres from a main road.
"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," said lead author Dr Hong Chen.
"More research to understand this link is needed, particularly into the effects of different aspects of traffic, such as air pollutants and noise."
So why is there a link?
Why does the risk of dementia get higher the closer you get to a main road?
You can thank traffic pollution. Apparently, long-term exposure to the pollutants nitrogen dioxide and fine particulate matter reduced brain matter. It also caused lower cognitive ability. And thanks to this study, we now know living close to high-traffic areas can cause dementia and other neurodegenerative diseases.
More research is needed before any conclusions can be made. Quoted in the Sydney Morning Herald, Professor Michael Woodward who advises Alzheimer’s Australia said “the study did not prove that traffic pollution caused dementia, and that there might be a knock-on effect of respiratory and cardiovascular problems linked to living in built-up environments. Dementia is already linked to cardiovascular problems.”
