Living close to a busy road may be linked to dementia, new research reveals.

Scientists on behalf of Public Health Ontario monitored 6.6 million residents of the Canadian city aged between 20 and 85. Incidences of dementia, multiple sclerosis and Parkinson’s disease were recorded for the eleven years between 2001 to 2012.

Cases of dementia were seven percent higher in those living within 50 meters of a major traffic road, and four percent higher for those 50 to 100 meters away.

The findings of the study were published in British medical journal The Lancet Thursday. The results showed that 243,611 cases of dementia were recorded, and approximately 9,000 and 32,000 cases of multiple sclerosis and Parkinson’s disease respectively. No link between participants living close to busy roads and the latter two diseases was recorded.

Dr. Hong Chen, one of the scientists behind the work, said in a widely reported statement that “increasing population growth and urbanization has 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.”

This is not the first time pollution has been linked to brain disease. Last September, researchers from Lancaster University in the U.K. found microscopic air pollution particles in human brains, which have been associated with causing brain diseases such as Alzheimer’s.

According to the World Health Organization in April 2016, nearly 50 million people worldwide suffer from dementia. CNBC reported last October that one in three seniors in the U.S. dies with either Alzheimer’s or dementia.

But, the latest research does not confirm a causal link between busy roads and dementia, Dr. David Reynolds, chief scientific officer at Alzheimer’s Research UK said in a statement.


“Conditions like dementia have multiple risk factors including age and genetics, and other social factors relating to where people live in cities could also be playing a part,” he explained.