A major study in Canada suggests that dementia is more common in people who live near main roads and busy areas than those who live further away.
The new study is bringing attention to the potential impact traffic pollution may have on a population’s health, in particular how it may increase the risk of dementia.
The study tracked 6.6 million people living in Ontario, Canada over the span of ten years ending in 2012.
What the research found was that there was a 7 percent higher risk of developing dementia in people who lived within 50 meters of a main road.
The risk decreased the further away people lived from the main roads; a 4 percent higher risk at 50-100 metres, a 2 percent higher risk at 101-200 metres.
The research concluded that there was no increase in risk of developing dementia in people who lived more than 200 metres away from the main road.
It should be clear that the results of the study only highlights that there is an association between living near a main road and risk of developing dementia – not to suggest that one’s living location can directly cause dementia.
The research, which was published on Thursday in The Lancet, was led by Dr Hong Chen.
Dr Chen said that busy roads could be a source of environmental stressors that may cause Dementia, “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”.
Dr Chen says this research is only the beginning, and that more needs to be done, “more research to understand this link is needed, particularly into the effects of different aspects of traffic, such as air pollutants and noise.”
What the Experts are Saying
Different experts have different theories as to why people closer to main roads have a higher risk of developing dementia.
Some researchers say long-term exposure to two common pollutants, nitrogen dioxide and fine particulate matter may be a cause.
A similar study has been conducted in the past looking at the association between traffic-related air pollution in schools and cognitive development in children, which found that there is reduced brain matter and lower cognition.
However, this new Canadian study is the first study to investigate the connection between living near heavy traffic and the onset of major neurodegenerative diseases.
Air pollution experts have acknowledged the study and believe that it should be further investigated to see if preventative measures can be taken.
They think the correlation that the study has found between main roads and Dementia may be attributed to air pollution, “a crucial global health concern for millions of people”.
Professor Michael Woodward, director of aged care research at Austin Health, suggests that dementia may be more common those near main roads because of factors such as lower socio-economic status, chronic stress and insomnia, which is more frequent in populations living near busy roads.
Dementia is linked to cardiovascular problems, which Professor Woodward believes may be a knock-on effect of respiratory and cardiovascular problems linked to living in built-up environments.
Professor Woodward, much like the Air pollution experts, says that the study should trigger more research as it could provide a new target for a preventative drug treatment. And that this new research should not cause people to move, “people should not be panicking if they live near a busy road.”
Though the research found a correlation between living near busy roads and dementia, the research found no link between living close to major roads and Parkinson’s disease or multiple sclerosis.