Last week, two scientific studies were published in the scientific journal The Lancet on the health effects of living near busy roads. One of these studies establishes a direct link between the traffic-related exposure to air pollution and an increased risk of dementia.

Dementia, Parkinson’s disease and multiple sclerosis

Researchers examined the incidence of dementia, Parkinson’s disease and multiple sclerosis in a population of 6.6 million individuals in Ontario, Canada, in the age groups of 20-50 (4.4 million individuals) and 55-85 years (2.2 million individuals). Based on the zip code of the home address, researchers determined the distance at which individuals lived from a busy road. Medical records were studied to identify individuals who developed a disease.

Between 2001 and 2012, a total of 243,611 individuals were diagnosed with dementia, 31,577 with Parkinson’s disease, and 9,247 with multiple sclerosis. No correlation was found between living near a busy road and Parkinson’s disease or multiple sclerosis. In contrast, dementia was significantly more prevalent in individuals living closer to a busy road.

Increased risk of dementia

The incidence of dementia was 7 percent higher in the population living within a distance of 50 meters from a busy road, 4 percent at a distance of 50 to 100 meters, and 2 percent between 100 and 200 meters. This correlation was even stronger in urban areas, and for individuals living within a distance of 50 meters from a busy road throughout their life (up to 12% increased incidence of dementia). Within the population living 200 to 300 meters from a busy road, no effect was observed.

In recent years, an increasing number of scientific publications have been published in which direct or indirect proof is presented for negative effects of air pollution on the nervous system. Traffic-related air pollutants, such as fine and ultrafine particles, nitrogen oxides (NOx), and carbon monoxide (CO) are proven risk factors for the development of neurodegenerative diseases, neuro-inflammation, developmental and cognitive disorders.