In a new study, researchers found that living near major roads or highways is linked to a higher incidence of dementia, Parkinson’s disease, Alzheimer’s disease and multiple sclerosis (MS).
They analyzed data for 678,000 adults in Metro Vancouver and found that living less than 50 meters from a major road or less than 150 meters from a highway is linked to a higher risk of developing dementia, Parkinson’s, Alzheimer’s and MS—likely due to increased exposure to air pollution.
The researchers also found that living near green spaces, like parks, has protective effects against developing these neurological disorders.
The study for the first time has 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.
The research was conducted by a team from the University of British Columbia.
Neurological disorders—a term that describes a range of disorders, including Alzheimer’s disease and other dementias, Parkinson’s disease, multiple sclerosis, and motor neuron diseases—are increasingly recognized as one of the leading causes of death and disability worldwide.
Little is known about the risk factors linked to neurological disorders, the majority of which are incurable and typically worsen over time.
For the study, researchers analyzed data for 678,000 adults between the ages of 45 and 84 who lived in Metro Vancouver from 1994 to 1998 and during a follow-up period from 1999 to 2003.
They estimated individual exposures to road proximity, air pollution, noise and greenness at each person’s residence using postal code data.
During the follow-up period, the researchers identified 13,170 cases of non-Alzheimer’s dementia, 4,201 cases of Parkinson’s disease, 1,277 cases of Alzheimer’s disease and 658 cases of MS.
For non-Alzheimer’s dementia and Parkinson’s disease specifically, living near major roads or a highway was associated with 14% and 7% increased risk of both conditions, respectively.
Due to relatively low numbers of Alzheimer’s and MS cases in Metro Vancouver compared to non-Alzheimer’s dementia and Parkinson’s disease, the researchers did not identify associations between air pollution and increased risk of these two disorders.
However, they are now analyzing Canada-wide data and are hopeful the larger dataset will provide more information on the effects of air pollution on Alzheimer’s disease and MS.
The team also found that green spaces appear to have some protective effects in reducing the risk of developing one or more of these disorders.
They say more research is needed, but the 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.
The lead author of the study is Weiran Yuchi, a Ph.D. candidate in the UBC School of population and public health.
The study is published in the journal Environmental Health.
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