Traffic Noise Raises Stroke Risk
As Traffic Noise Rises, So Does Risk of Stroke in Older People, Study Finds
Other Possible Stroke Causes Were Factored Out Before Conclusion Reached continued...
The data on where the study participants lived was linked to a noise calculation program that has been used to map noise levels in a number of locations in Scandinavia for several years. This program takes into account the amount of traffic congestion and speed, the type of road, such as rural or high-speed freeway, types of road surfaces, and the heights of people’s homes compared to the road surfaces.
At the start of the study, 35% of the people were exposed to noise levels greater than 60 decibels, and 72% lived at the same address through the end of the research project. The researchers’ lowest estimate for noise exposure was 40 decibels, and the highest was 82 decibels.
To put this into context, a jackhammer produces about 130 decibels and a jet plane taking off about 120.
Reasons for Link Between Noise and Stroke Are Not Clear
Sorensen says that though the mechanisms that would link noise to stroke remain undetermined, they likely are the same ones that are involved in the link of noise with hypertension and heart attacks.
The noise acts “as a stressor and disturbs sleep, which results in increased blood pressure and heart rate, as well as increased level of stress hormones,” she says. “Taken together, all of these could increase the risk for cardiovascular diseases.”
She says older people have more “fragmented sleep patterns” and are thus more susceptible to sleep disturbances, and that this fact could explain the apparent correlation between road noise and increased stroke risk in this age group.
“This is the first study on the association between transport noise and risk for stroke, as previous studies on transport noise focused mainly on hypertension and ischemic heart disease,” the authors write.
The study is published Jan. 26 in the European Heart Journal.