Traffic noise can increase the risk of dementia

There are situations that upset and cause many citizens to lose their balance: listening to loud horns when they are trapped in a traffic jam, stunned by the noise of trains and buses in an urban station, the screeching of the metro in every time you enter and exit the station, and even hear a sharp braking which can be heard from a fifth floor to the street.

Today, a study of two million adults, conducted over more than a decade, concluded that people living in areas subject to transport noise are faced with an increased risk of dementia, especially Alzheimer’s disease. The results were published in the magazine British Medical Journal (BMJ).

The researchers analyzed the relationship between long-term exposure to city traffic and rail noise and the possibility of developing a certain type of dementia between two million adults over 60 living in Denmark between 2004 and 2017. After excluding influencing factors related to residents and their neighborhoods, the study concluded that at least 1,216 of the 8,475 cases of dementia recorded in Denmark in 2017 could be attributed to transport noise. According to the report, “the diagnosis in approximately 963 patients was attributed to traffic noise and in 253 patients to railway noise”.

“In this large national cohort study, we found that noise from urban and rail transport is associated with an increased risk of dementia from all causes and subtypes of dementia, especially Alzheimer’s disease“, Determined the researchers, who found a model of higher risk with higher noise exposure. “If these results are confirmed in future studies, they could have a significant effect on estimating the burden of disease and health care costs attributed to transportation noise,” they said.

Why can noise affect mental health? Scientists who participated in the study assured that the release of stress hormones and sleep disturbances, which lead to heart disease, and changes in the immune system, are linked to the onset of dementia.

The study was observational and had a series of limitations, such as the lack of information on the sound insulation in private houses, which can affect noise exposure. However, its strengths included the large number of participants, the long follow-up period and the high-quality assessment of noise exposure.

Dementia is one of the biggest health problems in the world

Overall, it is estimated that around 130 million people will be living with the disease by 2050. Experts increasingly believe that environmental factors can play a role in the development of dementia. World Health Organization stated that “Noise pollution is not only an environmental nuisance but also a threat to public health.” The challenge is to reduce noise through transit programs, encourage walking or cycling, and design building codes.

Several dementia physicians, who were not involved in the study, gave their opinions on the report’s findings, Professor of Cognitive Neurology at Newcastle University, Timothy Griffiths, said it was “a large and impressive epidemiological study that has raised the question of why noise exposure is relevant for dementia.” Ivan Koychev, dementia expert and senior clinical researcher at the University of Oxford, said: “The results are reinforced by authors measuring and monitoring levels of traffic pollution, which has recently been found to be associated with dementia and other diseases ”.

Among the main conclusions of the report, it was suggested that it is possible reduce the burden of dementia by tackling traffic noise and the noise pollution it generates. “Expanding our knowledge of the harmful effects of noise on health is essential for prioritizing and implementing effective public health policies and strategies focused on the prevention and control of diseases, including dementia, ”the researchers concluded. .

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