A major study has claimed that living near a busy road could significantly increase the risk of developing Alzheimer’s and other forms of dementia.
In research published in The Lancet medical journal, scientist who tracked the progress of more than six million Canadian adults over 11 years found ‘a clear trend’ that incidents of dementia rose the closer people lived to main roads.
The study monitored the progress of every adult aged between 20 and 85 living in Ontario from 2001 to 2012, numbering around 6.6 million people. Over the decade long study 243,000 people went on to develop dementia. The researchers observed that nearly all of the people in the study, 95%, lived within one kilometre of a major road such as a motorway or A road, with half of the people living less than 200 meters away from a major road.
It showed that people living within 50 metres of heavy traffic had a seven per cent higher risk of developing dementia than those whose homes were more than 300 metres away.
The study went on to suggest a connection between dementia and exposure to two common traffic pollutants, nitrogen dioxide and fine particles generated by diesel engines.
Lead scientist Dr Hong Chen, from Public Health Ontario, said: “Our findings show the closer you live to roads with heavy day-to-day traffic, the greater the risk of developing dementia. With our widespread exposure to traffic and the greater tendency for people to live in cities these days, this has serious public health implications.
“Increasing population growth and urbanisation 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.
“More research to understand this link is needed, particularly into the effects of different aspects of traffic, such as air pollutants and noise.”
Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK, was less definite about the research and responded:
“There are 850,000 people in the UK living with dementia, and therefore interest in the risk factors driving the condition is high. This research is interesting in its identification of an association between dementia and major roads, but if any causal link exists between these two factors, it can’t be confirmed by this study.”
“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 here. This study has identified major roads and air pollutants from traffic as possible risk factors for dementia, a finding which will need further investigation before any firm conclusions can be drawn about the relative risks of air pollutants for dementia versus other risks such as smoking, lack of exercise or being overweight.”
“Studies like this are valuable in revealing new factors that could be implicated in Alzheimer’s disease and other dementias, and opening new avenues for further research. Alzheimer’s Research UK is funding research focusing on reducing the risk factors surrounding dementia, and is dedicated to finding a way of preventing or slowing down the progression of this devastating condition.”