People who live near busy roads laden with heavy traffic face a higher risk of developing dementia than those living farther away, according to researchers in Canada.

A study published in The Lancet medical journal found that people who lived within 50 meters (55 yards) of high-traffic roads had a 7.0 percent higher chance of developing dementia compared to those who lived more than 300 meters away from busy roadways.

"Air pollutants can get into the bloodstream and lead to inflammation, which is linked with cardiovascular disease and possibly other conditions such as diabetes. This study suggests air pollutants that can get into the brain via the bloodstream can lead to neurological problems," said Ray Copes, an environmental and occupational health expert at Public Health Ontario (PHO) who conducted the study with colleagues from Canada's Institute for Clinical Evaluative Sciences.