Traffic Noise Causes Stroke in Elderly People
According to a research by the Institute of Epidemiology Cancer Society in Copenhagen, Denmark , exposure to noise traffic which is very loud is associated with stroke in people aged 65 years old or more.
The researchers found that for every 10 decibels or more from road noise, a person’s risk of stroke increased by 27 percent. Researchers also found evidence that noise limit for elderly people is about 60 decibels. For those aged less than 65, a significant risk is not founded.
The study involved more than 57,000 people between the age of 50 and 64 who lives near Copenhagen and Aarhus between 1993 and 1997.
According to the study authors, Mette Sorensen, a senior researcher at the Institute of Epidemiology Cancer Society in Copenhagen Denmark, researchers analyzed medical records and location of their home during the period.
Researchers then measured the exposure of traffic noise. When starting the study, 35 percent of participants have been exposed to noise levels greater than 60 decibels, and the majority (72 percent) lived in the same address during the study. The researchers estimated that the lowest level of exposure to noise is 40 decibels and the highest to 82 decibels. The result shows that 1,881 people had a stroke.
While this is the first study linking traffic noise and stroke, they were not surprised with the results. “Most previous studies have found the traffic noise are associated with other cardiovascular disease,” said Sorensen.
The study authors noted that their study occurred in urban areas and do not represent all of Denmark. He said that further research is needed to confirm these findings.
Sorensen estimates that 600 new cases of stroke each year in his country can be linked with road traffic noise. The 5.5 million population of Denmark had 12,400 new cases of stroke each year. Sorensen believes stress could be a factor why people are attacked by stroke.
“Exposure to traffic noise is believed to provoke the stress response and interfere with sleep, which may increase the risk of strokes, through mechanisms including increased levels of stress hormones, increased heart rate and blood pressure and impaired immune systems,” said Sorensen. Other risk factors for stroke may also influence such as air pollution, aircraft noise, smoking, diet, alcohol and caffeine consumption.