New study shows that living near traffic may increase risk of dementia


The causes of dementia remain somewhat mysterious, making prevention and cure elusive. However,  scientists are making progress. A new study indicates that living near traffic is a causal factor of dementia.

It is generally accepted by scientists that when bacteria penetrate the thinning blood barrier in the brains of older people, the brain fights back by surrounding the bacteria with protein capsules called beta-amyloids. The bacteria are killed, but the protein capsules remain and are surrounded by tau proteins and diverse debris. The result is brain nerve cell death and inflammation. Alzheimer’s Disease, the most prevalent form of dementia, begins.

Scientists are targeting the protein and tau deposits that accompany onset in hopes of finding a cure. Yet, the authors of the World Alzheimer’s Report of 2016 maintain there is an emerging consensus among scientists that there are “potentially modifiable” lifestyle factors that may prevent dementia.  These factors include not smoking, not using alcohol immoderately, eating a nutritious diet, exercising,  and keeping hypertension at bay.

Now, a new modifiable lifestyle factor has been introduced to prevent dementia. A recent study published in The Lancet shows that living near a busy road contributes to the development of dementia. The study tracked seven million Canadian residents for more than ten years.


Risk of dementia declined with distance from traffic

This is not good news for urban dwellers and people whose homes are not far from major highways. The study found that people who live within about 165 feet (about 50 meters) of a major road are more prone to develop dementia than those who live further from traffic.

The risk was directly related to distance or proximity to a significant thoroughfare. The risk declined as distance increased. People who lived within 165 feet ran a seven percent higher risk of developing dementia than those living farther away. The risk dwindled to 1% for those who lived over 600 feet from a major road and reduced to virtually nothing for those living 1,000 feet away.

Because dementia is a growing global concern, any lifestyle changes that may prevent it are extremely important. The World Alzheimer’s Report 2016 says about 47 million people have dementia in the world today. The report notes that this number is greater than the entire population of Spain. By 2050, the authors warn, the number is projected to exceed 130 million. Beyond the sheer number of persons afflicted with dementia, the costs are also staggering. Presently, the disease costs more than $800 billion annually and is expected to exceed $1 trillion by 2018.


Preventive measures are crucial for dementia

Even at these costs, nearly half of dementia patients live without a diagnosis and proper care. The costs of providing dementia patients the care they deserve and need would undoubtedly be much higher than the staggering amount it costs today if all dementia sufferers were properly diagnosed.

Even though wealthy countries can now provide medical services comprehensively, the number of people who will be flooding the system may very well cause bottlenecks and lack of care. In middle-income countries, it is a different story. Medical services to dementia patients tend to be concentrated in city hospitals. Poorer countries have less developed healthcare delivery systems for dementia patients. The disease takes its greatest toll there.

Thus, potentially modifiable lifestyle factors are important in fighting dementia. Family members of aging loved ones who live in urban areas or near major highways might want to rethink their locations. With dementia, that ounce of prevention may well be worth a pound of cure, especially because a cure remains elusive.



Chen, H., Kwong, J., Copes, R., Tu, K., Villeneuve, P. J., van Donkelaar, A., Hystad, P., Martin, R. V., Murray, B. J., Jessiman, B., Wilton, A. S., Kopp, A., Burnett, R. T. (January 4, 2017). Living near major roads and the incidence of dementia, Parkinson’s disease, and multiple sclerosis: a population-based cohort study. The Lancet. DOI: Available online at Accessed January 24, 2017.

Prince, M., Comas-Herrera, A., Knapp, M., Guerchet, M., Karagiannidou, M. (September 2016). World Alzheimer Report 2016. Alzheimer’s Disease International. Available online at Accessed January 24, 2017.

The Lancet. (January 5, 2017). Living Close to Major Roads Linked to Small Increase in Dementia Risk. Available online at: Accessed January 24, 2017.

Travers, C., Martin-Khan, M., Lie, D. (2009). Barriers and enablers of health promotion, prevention and early intervention in primary care: Evidence to inform the Australian national dementia strategy. Australas J Ageing 28: 51–7. Available online at Accessed January 24, 2017.