Researchers in Denmark have identified prolonged exposure to traffic noise on the streets as a higher risk factor for developing dementia in a person. An article by scientists was published in The BMJ magazine.
Scientists from the universities of Copenhagen, Aarhus and southern Denmark have evaluated the noise from street and rail traffic on the facades of every house in the country. The researchers also identified more than 103,000 Danes over the age of 60 who were diagnosed with dementia between 2004 and 2017.
Exposure to street noise for ten years was found to be associated with an increased risk of developing dementia of all kinds. Of the 8,475 dementia cases reported in Denmark in 2017, 1,216 were associated with street noise. Of these, 963 cases were associated with road traffic and 253 with rail traffic.
Noise from road traffic with a capacity of more than 55 decibels increased the risk of developing Alzheimer’s disease by 27 percent and that of 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 was correlated with an increase in noise power, although it decreased slightly when it reached the highest levels.
According to the researchers, such a relationship can be explained by increased release of stress hormones and sleep disturbances that lead to coronary heart disease.