Long term exposure to noisy traffic could lead to dementia

Exposure to noisy traffic over a long period could cause dementia, according to new research.

The study, published in the BMJ by researchers from Denmark, found that around one in eight cases of dementia in the country could be linked to "noise exposures" from roads and railways.

Currently more than 55 million people live with dementia worldwide, and there are nearly 10 million new cases every year. The number of people with dementia is expected to exceed 130 million by 2050.

In Australia, dementia is the second leading cause of death, but the leading cause of death for women.

In 2021, there are an estimated 472,000 Australians living with dementia and by 2058 that figure is expected to reach 1.1 million people.

The Danish researchers looked at the association between long term residential exposure to road traffic and railway noise and risk of dementia among two million adults aged over 60 between 2004 and 2017.

Over that period they found 103,500 new cases of dementia. They also found that a 10-year average exposure to road traffic and railway noise was associated with a higher risk of all-cause dementia.

The researchers estimate that as many as 1,216 out of the 8,475 cases of dementia registered in Denmark in 2017 were likely to have been caused by exposure to noise.

Transportation noise is considered the second worst environmental risk factor for public health in Europe after air pollution.

The researchers hypothesise that prolonged exposure to noise results in the release of stress hormones and sleep disturbance which lead to coronary artery disease and changes in the immune system and inflammation – all of which are seen as early events in the onset of dementia and Alzheimer’s disease.

“If these findings are confirmed in future studies, they might have a large effect on the estimation of the burden of disease and healthcare costs attributed to transportation noise," the authors wrote.

"Expanding our knowledge on the harmful effects of noise on health is essential for setting priorities and implementing effective policies and public health strategies focused on the prevention and control of diseases, including dementia.”

September 20-26 is Dementia Action Week. You can find out more here.

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