People who live in or near roads with high traffic are more likely to develop dementia than their peers who live further away.
In a new study published in the journal The Lancet, researchers have found that those who live closest to high-traffic roads have up 12 percent increased risk of getting diagnosed with the neurological disease.
Proximity To High-Traffic Roads And Risk For Dementia
Researchers tracked about 6.6 million people in Canada for more than a decade. Of the participants, 243,611 developed dementia over the study period between 2001 and 2012.
When the researchers mapped the proximity of the participants to major roadways based on postal codes, they found that those who lived within 50 meters of busy roads had 7 percent increased likelihood of developing dementia compared with those who live more than 300 meters away from high-traffic roadways.
The increased risk for dementia was 4 percent higher for those who lived between 50 and 100 meters from major traffic and 2 percent higher for those who lived within 101 to 200 meters. The elevated risk fades away for those who live more than 200 meters from high-traffic roads.
"The associations were robust to sensitivity analyses and seemed stronger among urban residents, especially those who lived in major cities and who never moved," the researchers wrote in their study, which was published on Jan. 4.
Dementia And Alzheimer's Disease
Dementia is attributed to loss of brain cells, which affects a person's memory, behavior, thinking and ability to perform everyday activities. Alzheimer's disease accounts for 60 to 80 percent of all dementia cases.
Figures from the World Health Organization show that the number is people with dementia in 2015 is about 47.5 million and the number is expected rise as societies age and in the absence of an effective treatment.
While studies have suggested of lifestyle practices that can help reduce risks of developing the illness such as getting adequate sleep, eating heart-friendly diet and doing brain exercises, no treatment that can reverse or stop the progression of the condition for those who already have it is currently available. Some drug treatments, however, can improve the symptoms of the condition.
Air Pollutants, Cardiovascular Diseases And Neurological Problems
Earlier studies have shown that air pollutants can get into the bloodstream and cause inflammation associated with cardiovascular diseases and other conditions such as diabetes.
The new study suggests that air pollutants may also get into the brain through the bloodstream which can cause neurological problems, said study author Ray Copes from Public Health Ontario, and colleagues.
Experts said that the study provides another important reason why it is important to clean up the air in the cities.
Emission from coal plants and industrial plants are known to contribute to air pollution. Vehicle emissions are also among the primary contributors of air pollution in urban areas.
Copes advised those who live in cities to consider walking along side streets, go for cycle routes along quieter roads and jogging in parks. He added that air pollution should be considered in urban planning and designing buildings to reduce exposure to harmful pollutants.