VANCOUVER, British Columbia — Numerous studies have found an association between living close to nature and improved mental health. Now, on the opposite end of the spectrum, a recent set of research conducted at the University of British Columbia finds that living near major roads or highways can raise one’s risk of developing various neurological disorders like Alzheimer’s, dementia in general, Parkinson’s, and multiple sclerosis.
Data on over 678,000 adults living in the metropolitan Vancouver area was assessed for the study, and researchers concluded that living less than 164 feet from a major road or living less than 492 feet from a highway is linked to a noticeably higher risk of developing the aforementioned conditions. While the study’s authors can’t say with 100% certainty, air pollution caused by passing cars is almost certainly the cause of these findings.
Meanwhile, the study also found additional evidence that living near some greenery, such as a park, can actively protect against neurological problems.
“For the first time, we have confirmed a link between air pollution and traffic proximity with a higher risk of dementia, Parkinson’s, Alzheimer’s and MS at the population level,” says Weiran Yuchi, the study’s lead author and a PhD candidate in the UBC school of population and public health, in a release. “The good news is that green spaces appear to have some protective effects in reducing the risk of developing one or more of these disorders. More research is needed, but our findings do suggest that urban planning efforts to increase accessibility to green spaces and to reduce motor vehicle traffic would be beneficial for neurological health.”
All of the data used in the analysis came from adults between the ages of 45-84 who had lived in Vancouver from 1994-1998, and then again during a second observation period of 1999-2003. Using local postal codes, researchers estimated each adult’s proximity to nearby roads and subsequent exposure rates to air pollution, noise, and green spaces. Over the course of both follow-up periods, 13,170 cases of non-Alzheimer’s dementia popped up, 4,201 cases of Parkinson’s disease occurred, 1,277 Alzheimer’s diagnoses were noted, as well as 658 cases of MS.
Regarding non-Alzheimer’s dementia and Parkinson’s disease, living near a major road or highway was associated with a 14% increased risk of dementia and 7% increased risk of Parkinson’s. There weren’t enough documented cases of Alzheimer’s or MS for researchers to formulate associations between air pollution levels and one’s risk of developing the two disorders. However, the study’s authors are currently analyzing a much larger Canadian dataset and are hopeful they will be able to come to more concrete conclusions on the impact of air pollution on Alzheimer’s disease and MS.
Green spaces were found to mitigate the negative effect of air pollution on neurological disorder development, researchers say.
“For people who are exposed to a higher level of green space, they are more likely to be physically active and may also have more social interactions,” comments Michael Brauer, the study’s senior author and professor in the UBC school of population and public health. “There may even be benefits from just the visual aspects of vegetation.”
The study is published in Environmental Health.