The Narwhal proximity to major road neurological disease Vancouver Lion's Gate Bridge

Living close to major roads leads to higher risk of Parkinson’s and dementia: UBC study

New research analyzing more than 650,000 individuals in Vancouver found proximity to sources of air pollution can affect neurological health — but green space has protective effects

The results of a UBC study published in the peer-reviewed medical journal Environmental Health in January 2020 suggest air pollution and living close to major roads is connected to a higher risk of Parkinson’s disease and dementia.

“We wanted to understand who develops these neurologic diseases and who does not,” Dr. Michael Brauer, professor in the University of British Columbia’s School of Population and Public Health and one of the study’s authors, told The Narwhal. 

“We wanted to know, if you live close to a major road, were you more likely to develop a disease than somebody who did not live close to a major road?”

The study analyzed data for 678,000 individuals ages 45 to 84 living in Metro Vancouver between 1994 and 2003. As well as administrative health data, each individual’s proximity to a major road, exposure to air pollution, exposure to traffic noise and proximity to green space was analyzed based on their postal codes.

Why consider the population’s neurological health?

This study focused on four neurological disorders: Parkinson’s disease, multiple sclerosis (MS), Alzheimer’s disease and non-Alzheimer’s dementia. All of them are progressive diseases, meaning symptoms will gradually worsen over time.

Neurological diseases, including the four studied, are one of the leading causes of disability in Canada. None of the four disorders have a known cure and cost Canada’s health care system billions.

Brauer said that little is known about why some individuals develop these disorders and others don’t — particularly beyond aging, a known risk factor. Understanding the role the environment and urban design play could result in preventative measures being taken, and in turn, savings in health spending.

A connection to fine particulate matter

Medical data like physician codes, hospitalization data, medical billing data and prescription drug information was analyzed to determine if individuals who did not have neurological disorders between 1994 and 1998 then developed Parkinson’s disease, MS, Alzheimer’s disease or dementia in the years between 1999 and 2003.

Results showed that living less than 50 metres from a major road or less than 150 metres from a highway was associated with a 14 per cent increased risk for non-Alzheimer’s dementia and a seven per cent increased risk for Parkinson’s disease. 

Brauer notes that the number of Alzheimer’s disease and MS cases was low, meaning a relationship between road proximity, air pollution and these neurologic disorders can’t be made.

The hypothesis is that the increased risk for cognitive disorders based on road proximity has to do, at least in part, with a connection to fine particulate matter, nitrogen dioxide and nitric oxide in the air.

Lynn Canyon Park Andy Li

A tree in Vancouver’s 617-acre Lynn Canyon Park. The UBC study found proximity to green spaces has protected effects for neurological health. Photo: Andy Li

‘Green spaces protect you against its effects’

However, the results found proximity to green spaces — street trees and parks — has protective effects, even if there is still air pollution and if the individual lived near a major road.

“Even though people were [neurologically] affected by air pollution, they were less affected if where they lived was greener,” Brauer said.  

Brauer said the findings show we should be thinking about incorporating greenery and parks into residential neighbourhoods, as well as relying less on motor vehicles and separating motor vehicles from where people are spending time, to benefit Canadians’ neurological health.

However, more research still needs to be done. Next, Brauer and his team plan to expand this study beyond Metro Vancouver.

“[Analyzing] a larger population will also allow us to look at more combinations of noise, air pollution, road proximity and green space,” Brauer said. “And perhaps [we can] untangle a little bit more about what’s going on with regard to the aging population’s neurological health.” 

Like a kid in a candy store
When those boxes of heavily redacted documents start to pile in, reporters at The Narwhal waste no time in looking for kernels of news that matter the most. Just ask our Prairies reporter Drew Anderson, who gleefully scanned through freedom of information files like a kid in a candy store, leading to pretty damning revelations in Alberta. Long story short: the government wasn’t being forthright when it claimed its pause on new renewable energy projects wasn’t political. Just like that, our small team was again leading the charge on a pretty big story

In an oil-rich province like Alberta, that kind of reporting is crucial. But look at our investigative work on TC Energy’s Coastal GasLink pipeline to the west, or our Greenbelt reporting out in Ontario. They all highlight one thing: those with power over our shared natural world don’t want you to know how — or why — they call the shots. And we try to disrupt that.

Our journalism is powered by people just like you. We never take corporate ad dollars, or put this public-interest information behind a paywall. Will you join the pod of Narwhals that make a difference by helping us uncover some of the most important stories of our time?
Like a kid in a candy store
When those boxes of heavily redacted documents start to pile in, reporters at The Narwhal waste no time in looking for kernels of news that matter the most. Just ask our Prairies reporter Drew Anderson, who gleefully scanned through freedom of information files like a kid in a candy store, leading to pretty damning revelations in Alberta. Long story short: the government wasn’t being forthright when it claimed its pause on new renewable energy projects wasn’t political. Just like that, our small team was again leading the charge on a pretty big story

In an oil-rich province like Alberta, that kind of reporting is crucial. But look at our investigative work on TC Energy’s Coastal GasLink pipeline to the west, or our Greenbelt reporting out in Ontario. They all highlight one thing: those with power over our shared natural world don’t want you to know how — or why — they call the shots. And we try to disrupt that.

Our journalism is powered by people just like you. We never take corporate ad dollars, or put this public-interest information behind a paywall. Will you join the pod of Narwhals that make a difference by helping us uncover some of the most important stories of our time?

See similar stories

Feds propose to protect critical spotted owl habitat 1,000 times the size of Stanley Park

Twenty-one years after the spotted owl was listed as endangered under Canada’s Species at Risk Act, on Thursday the federal government released a proposed recovery...

Continue reading

Recent Posts

Our newsletter subscribers are the first to find out when we break a big story. Sign up for free →
An illustration, in yellow, of a computer, with an open envelope inside it with letter reading 'Breaking news.'
Our newsletter subscribers are the first to find out when we break a major investigation. Want in? Sign up for free to get the inside scoop on The Narwhal’s reporting on the natural world.
Hey, are you on our list?
An illustration, in yellow, of a computer, with an open envelope inside it with letter reading 'Breaking news.'
Our newsletter subscribers are the first to find out when we break a major investigation. Want in? Sign up for free to get the inside scoop on The Narwhal’s reporting on the natural world.
Hey, are you on our list?
An illustration, in yellow, of a computer, with an open envelope inside it with letter reading 'Breaking news.'