Researchers in Denmark have identified long-term exposure to traffic noise on the streets as a factor in a person’s increased risk of developing dementia. An article by scientists was published in the journal The BMJ.
Scientists from the universities of Copenhagen, Aarhus and South Denmark have evaluated the noise from street and rail traffic for the facades of all houses in the country. The researchers further identified more than 103,000 Danes over 60 who were diagnosed with dementia from 2004 to 2017.
It was found that exposure to street noise for ten years was associated with an increased risk of developing dementia of all types. Of the 8,475 cases of dementia reported in Denmark in 2017, 1,216 were associated with street noise. Of these, 963 cases were associated with road traffic and 253 with railway traffic.
The noise from road traffic with a capacity of more than 55 decibels increased the risk of developing Alzheimer’s disease by 27 percent, and from rail traffic by 24 percent. However, the risk of vascular dementia increased only when exposed to traffic noise. At the same time, as the researchers note, the risk of developing dementia in general correlated with an increase in noise power, although it slightly decreased when it reached the highest levels.
According to the researchers, this relationship may be explained by the increased release of stress hormones and sleep disturbances leading to coronary heart disease.