Living near major roads or highways is linked to an increased risk of neurological disorders, according to a new study by UBC researchers.
According to the study published last week in the journal Environmental Health — which looked at the effects of proximity to traffic or green space, and noise and air pollution — people living less than 50 metres from a major road, or less than 150 metres from a highway, have a higher chance of developing dementia, Parkinson’s disease, Alzheimer’s and multiple sclerosis (MS).
This increased risk is likely due to exposure to more air pollution, such as fine particulate matter and nitrogen dioxide.
“For the first time, we have a confirmed link between air pollution and traffic proximity with a higher risk of dementia, Parkinson’s, Alzheimer’s and MS at the population level,” said Weiran Yuchi, the study’s lead author and UBC PhD candidate.
According to the researchers, little is known about the risk factors associated with neurological disorders, which are increasingly recognized as one of the leading causes of death and disability worldwide.
The researchers looked at 678,000 Metro Vancouver adults between the ages of 45 and 84, who all lived in the region from 1994 to 1998, and then followed up with those adults from 1999 to 2003.
Using postal codes, the researchers determined how close these people lived to major traffic routes, and their exposure to air pollution, noise and green spaces.
During the follow-up period, researchers identified 13,170 cases of non-Alzheimer’s dementia, 4,201 cases of Parkinson’s disease, 1,277 cases of Alzheimer’s and 658 cases of MS.
Living near a highway or a major road was specifically linked to a 14 per cent increased risk of non-Alzheimer’s dementia and a seven per cent increased risk of Parkinson’s disease.
While road proximity was also associated with a risk factor for Alzheimer’s and MS, the research team was unable to identify a percentage for that risk, and are now examining data from across the country.
Conversely, the study also found that living within 100 metres of green spaces, such as parks, has “protective effects” against developing those neurological disorders.
“For people exposed to a higher level of green space, they are more likely to be physically active and may also have more social interactions,” said Michael Brauer, the study’s senior author and UBC professor.
“There may even be benefits from just the visual aspects of vegetation.”
The study highlights the importance of incorporating greenery and parks in city planning, particularly for residential neighbourhoods, according to researchers.