People who live close to busy roads are at a higher risk for contracting dementia, new research suggests. In fact, as many as 11% of dementia cases in people who live within 50 meters of a major thoroughfare can be blamed on traffic.
The researchers tracked nearly two million people in Canada for 11 years, and came to the conclusion that air pollution or noisy traffic could be adding to the degeneration of the brain’s function, the BBC reports.
The study focused on people in Ontario from 2001 and 2012, when there were 243,611 cases of dementia diagnosed at the time. The risk for this degenerative condition was highest in those living closest to main highways.
According to the researchers, compared to those living 300 meters away from a major road, the risk was 7% higher within 50 meters, 4% higher between 50-100 meters, 2% higher between 101-200 meters. Their analysis adjusted their analysis to account for other risk factors such as poverty, education levels, obesity and smoking.
However, the direct causes of dementia are still yet to be fully understood.
Dr. Hong Chen from Public Health Ontario, one of the authors, said,
Increasing population growth and urbanisation have 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.
He added that more research is necessary to understand the link between dementia and traffic, especially on air and noise pollutants.
The study’s data adds to the list of reasons people should avoid polluted air in cities. The World Health Organization reports that up to three million people die annually due to outdoor air pollution – this increases the risk of stroke, lung cancer, heart disease and respiratory illnesses.
It is still unclear, however, if dementia will be added to that list.
The study was published in the Lancet.