"Chronic noise burden is associated with the risk of [heart attack]," German doctors write in the European Heart Journal.
They're talking about a steady stream of noise at home or at work, such as the din of traffic, the clatter of construction, or the hustle and bustle of a big, busy office.
Offices and cities needn't be silent, but turning the volume down a bit might help hearts, researcher Stefan Willich, MD, and colleagues write.
How does noise raise heart attack risk? It could be a consequence of noise-related stress, Willich's team notes.
Willich directs the Institute for Social Medicine, Epidemiology, and Health Economics at Berlin's Charite University Medical Centre.
Heart Attack Study
Willich's study covered 4,115 heart attack survivors from 32 major hospitals in Berlin from 1998 to 2001. Most patients were men in their mid-50s.
Patients rated their daily noise exposure in recent years before their heart attacks. They also rated their annoyance at that noise.
The researchers used traffic maps, charting where each patient lived. They also checked workplace noise levels.
For comparison, patients from the same hospitals who hadn't had heart attacks were also included.
Noisy Setting, Greater Heart Attack Risk
Chronic noise was linked to a "mildly to moderately" increased heart attack risk, write the researchers.
Annoyance from noise was less important than the noise itself, the study shows.
Two slight differences were seen between men and women. Women's heart attack risk was more affected by annoyance from environmental noises. Those included city sounds but not workplace noises.
However, men's heart attack risk was more strongly linked to annoyance from workplace noises.
"One possible explanation is that women in our study may have spent more time at home when compared with men," the researchers write. They call for more studies of how noise affects men's and women's heart attack risk.
Familiar Risk Factors
Noise certainly wasn't the only heart danger seen in the patients.
The usual suspects -- such as smoking, diabetes, high blood pressure, and high levels of blood fats -- also raised the risk of heart attack.
Combining those risk factors could be a bad mix, Willich writes. For instance, someone who smokes while on deadline in a noisy office could have a higher heart attack risk, the researchers note.
They add that the findings may not extend to people who die of heart attacks, rural patients, and people older than 70. Those groups weren't included in the study.
How Noise Hurts The Heart
Willich's study doesn't prove that noise caused any of the patients' heart attacks.
Patients weren't exposed to noise to see how their hearts fared. Instead, the researchers noted patterns in heart attacks and noise exposure.
A certain threshold -- about 60 decibels of street noise -- was important, the researchers report. Beyond that threshold, higher noise levels didn't worsen heart attack risk.
In Europe, workers exposed to 85 or more decibels of noise are supposed to wear ear protection (such as during construction). That policy might protect ears, but not hearts, write Willich and colleagues.
Sources: Willich, S. European Heart Journal, Nov. 24, 2005; online edition. News release, MW Communications.
By Miranda Hitti
Reviewed by Louise Chang, MD
© 2005, WebMD Inc. All rights reserved