Road traffic and railway noise is associated with an increased risk of dementia, a study suggests
Researchers in Denmark monitored almost two million adults aged 60 or older living in the country between 2004 and 2017.
The study, published in the BMJ, found that over an average of eight-and-a-half years, 31,219 participants received a diagnosis of Alzheimer's disease, 8664 a diagnosis of vascular dementia, and 2192 a diagnosis of Parkinson's disease-related dementia.
The researchers estimated exposures to road traffic and railway noise at the most and least exposed facades of buildings for all residential addresses in Denmark, and said they had at least 10 years of address history for all the participants.
They calculated the population-attributable risk for road traffic and railway noise and concluded that of the 8475 new cases of dementia registered in the country in 2017, "the diagnosis in an estimated 963 patients was attributed to road traffic noise and in 253 patients to railway noise".
While the researchers said their work was a large population study with a long follow-up period, they acknowledged its limitations included a lack of information on lifestyle factors, which are recognised risks for dementia.
But they said their models did include several socioeconomic variables associated with lifestyle.
Confirmation by future studies could help reveal the impact transport noise has on disease and healthcare costs, they said.
More research was "essential for setting priorities and implementing effective policies and public health strategies focused on the prevention and control of diseases, including dementia".
Dr Rosa Sancho, head of research at Alzheimer's Research UK, said the research did not give the cause of the increased dementia risk but added to evidence linking exposure to noise pollution and dementia.
"While this is a large observational study using detailed estimates of residential noise levels, it only considers road and rail noise and doesn't evaluate established lifestyle risk factors for dementia, which could have also attributed to the increased risk of dementia," Sancho said.
She said current evidence suggested the best ways to support brain health were still staying active, eating a healthy diet, not smoking, and keeping weight, cholesterol and blood pressure in check.
Australian Associated Press
