In a new study from the University of Southern Denmark, researchers found exposure to noise from traffic on roads and railways over a long period is associated with a higher risk of developing dementia, especially Alzheimer’s disease.
They estimated that as many as 1,216 out of the 8,475 cases of dementia registered in Denmark in 2017 could be attributed to these noise exposures, indicating a great potential for dementia prevention through a reduction in traffic-related noise.
Worldwide, the number of people with dementia is expected to exceed 130 million by 2050, making it a costly and growing global health crisis.
Besides well-established risk factors, such as heart diseases and unhealthy lifestyles, environmental exposures may also play a role in the development of dementia.
Transportation noise is considered the second-worst environmental risk factor for public health in Europe after air pollution.
Around a fifth of the European population is exposed to transportation noise above the recommended level of 55 dB (decibels).
In the study, the team examined the association between long-term residential exposure to road traffic and railway noise and risk of dementia among two million adults aged over 60 and living in Denmark between 2004 and 2017.
They found 103,500 new cases of dementia during a 8.5-year period. A 10-year average exposure to road traffic and railway noise at the most and least exposed sides of buildings was linked to a higher risk of all-cause dementia.
These associations showed a general pattern of higher risk with higher noise exposure but with a leveling off or even small declines in risk at higher noise levels.
Further analysis showed both road traffic and railway noise were linked to a higher risk of Alzheimer’s disease—up to 27% higher for exposure to road traffic noise of 55 dB and up to 24% higher for exposure to railway noise of 50 dB compared with less than 40 dB.
However, only road traffic noise was associated with an increased risk of vascular dementia, and not railway noise.
Possible explanations for the effect of noise on health include the release of stress hormones and sleep disturbance, leading to a type of coronary artery disease, changes in the immune system and inflammation—all of which are seen as early events in the onset of dementia and Alzheimer’s disease.
The team says expanding the 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.
If you care about dementia, please read studies about 40% of dementia cases could be prevented by avoiding 12 things throughout life and findings of this gut problem may double your dementia risk.
For more information about dementia and your health, please see recent studies about common heartburn drugs may increase dementia risk and results showing that this vitamin deficiency may lead to alcohol-related dementia.
The study is published in The BMJ. One author of the study is Manuella Lech Cantuaria.
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