A new study funded by Health Canada suggests people who live close to a highway or major road could have a higher risk of developing dementia.

The study, published by U.K medical journal The Lancet, investigated the association between residential proximity to major roadways and the incidence of dementia, Parkinson’s disease and multiple sclerosis.

Researchers found that Ontario residents who lived within 50 metres of heavy traffic roadways had a 7% increased likelihood of developing dementia, compared to those who live more than 300 metres away. They did not, however, find any link to Parkinson’s disease or multiple sclerosis.

The study looked at health records for more than six million Ontario residents, aged 20 to 85, who have lived in the province for at least five years and are Canadian-born.

According to researchers, air pollution from vehicles may be a factor in the development of the neurological diseases.