Thursday, 24 November 2005

Noise increases the risk of having a heart attack

Too much noise, such as the sound of passing traffic, can increase the risk of heart attack in men by 50 per cent and in women by up to threefold. That’s according to a team of German researchers who interviewed 4,115 hospital inpatients, about half of whom were recovering from a recent heart attack; the remainder served as controls.

Stefan Willich and colleagues interviewed the patients about their experiences of noise at home and at work, and used a Berlin ‘noise map’, and work-place assessments to corroborate the participants’ statements.

In men, both higher noise at home and at work were associated with increased risk of having a heart attack, whereas for women only noise at home was a factor, possibly because the female participants tended to spend more time at home. In women only, risk of heart attack was also independently related to the annoyance caused by noise, rather than just noise levels per se. Other known risk factors such as smoking and diabetes were controlled for throughout these analyses.

The researchers said “Sound pressure levels and/or annoyance by noise may enhance psychological stress and anger and lead to impaired physiological factors such as increasing catecholamine levels associated with increased blood pressure and plasma lipids [known risk factors for heart attack]”.

The researchers also noted that the risk of heart attack did not rise proportionately with noise levels, rather there seemed to be a cut off so that participants who experienced noise levels above 60 decibels (the level typical in a busy office) were exposed to increased risk of heart attack relative to participants who only experienced noise below 60 decibels.

Current European Union regulations are that workplace noise should not be higher than 85 decibels. On this the researchers said “The results emphasize the need to reassess the importance, in general, and the adequate thresholds, in particular, of wearing ear protection at work places. The currently used threshold of 85 decibels may protect sufficiently from hearing damage but not from cardiovascular risk”.
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Willich, S.N., Wegscheider, Stallman, M. & Keil, T. (2005). Noise burden and the risk of myocardial infarction. European Heart Journal, In Press, DOI: 10.1093/eurheartj/ehi658.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

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