Study links noisy environment to heart attacks

NEW YORK - Living or working in noisy surroundings may raise a person's risk of heart attack, a new study suggests.

Researchers in Germany found that urban middle-aged adults who lived near high-traffic roads were 46 per cent more likely to have a heart attack than those who lived in more peaceful neighbourhoods.

Similarly, men whose jobs exposed them to high noise levels were one-third more likely to have a heart attack than their peers in quieter workplaces.

The reason for these associations is not completely clear, but the stress of dealing with chronic noise may be involved, according to the researchers, led by Dr Stefan Willich of Charite University Medical Centre in Berlin.

Several studies have suggested that long-term exposure to traffic noise or loud workplaces such as factory floors may contribute to high blood pressure and heart attack risk.

To the body, loud noise acts as a "warning," and the normal stress response involves hormonal changes and a spike in blood pressure and heart rate.

Researchers suspect that over time, chronic noise exposure may damage the cardiovascular system.

In the present study, published in the European Heart Journal, the researchers considered the actual sound levels of neighbourhoods and workplaces, and study participants' perceptions of the noise.

They found that women who said they were "annoyed" by traffic noise around their homes were at greater heart attack risk than women who were unfazed. But men's annoyance levels, at home or work, were unrelated to heart attack risk.

By objective measures - based on official traffic-noise data for Berlin - men and women who lived off noisy roads had an elevated heart attack risk. Objective measures of workplace noise were related to heart attack risk only among men.

The gender differences, according to Willich's team, may reflect the fact that men are more likely to work in particularly noisy industries, while women may be more likely to be home during the day - and annoyed by surrounding traffic.

The study included 4115 people, mostly in their 50s, who had been treated for a heart attack in a Berlin hospital. They were compared with a control group of adults the same age without a heart attack history.

Even with heart risk factors considered - such as smoking, obesity and family history of heart attack - people with greater noise exposure had a higher risk of attack.

Whether protective gear for the ears, worn to prevent hearing damage, may also lower heart risks is unclear.

But the findings, say the researchers, point to a need to study the question.

- REUTERS