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Noisy workplace doubles heart risk

Working in a persistently noisy environment doubles risk of heart disease

Louise Prime

Thursday, 07 October 2010

People who usually work where noise is so loud that they have to raise their voice to be heard have at least double the risk of serious heart disease, research from the US has shown. The increase in risk is particularly strong for men aged less than 50 who smoke, say the study authors in this week’s online Occupational and Environmental Medicine.

They examined data from the US National Health and Nutrition Examination Survey (NHANES), which followed more than 6000 adults from 1999 to 2004. Participants in NHANES had been interviewed about their lifestyle, occupational health, medical examinations and blood tests. The researchers divided them into those who endured persistent loud noise at work, to the extent that it was difficult to talk at normal volume – for at least three months – and those who did not.

More than a fifth (21%) of people in the study said that they had endured noisy conditions at work for an average of nearly 9 months. Most of these were men younger than 50, who on average both smoked and weighed more than participants who had a quieter workplace.

The authors said: “After adjustment for various covariates … there were clear exposure–response relationships for the observed associations.”

People with chronic noise exposure were 2-3 times more likely to have angina pectoris, myocardial infarction, CHD and isolated diastolic hypertension as people with quiet workplaces. The risk of angina, coronary heart disease or heart attack rose to 3-4 times greater for workers under 50.

Workers exposed to persistent noise did not have significantly increased levels of cardiovascular biomarkers including blood lipids and circulating inflammatory mediators. They were, however, twice as likely to have isolated diastolic hypertension as those who weren’t working in noisy environments.

The authors suggest that enduring persistent loud noise could be as strong an external stressor as sudden strong emotion or physical exertion, the effect of which is to prompt various chemical messengers to constrict blood flow through the coronary arteries.

They conclude: “This study suggests that excess noise exposure in the workplace is an important occupational health issue and deserves special attention.”

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