VANCOUVER, British Columbia, Oct. 6 (UPI) -- A study of more than 6,000 U.S. workers found a persistently noisy workplace more than doubled serious heart disease risk, Canadian researchers say.

Study leader Wenqi Gan of the University of British Columbia used data from employees ages 20 and older who were part of the U.S. National Health and Nutrition Examination Survey from 1999 to 2004. The researchers had data involving household interviews on lifestyle and occupational health, medical examinations and blood tests.


The researchers compared two groups of workers -- one employed where they heard persistent loud noise to the extent that it was difficult to talk at normal volume for at least three months, and a second group that worked in quieter places.

Twenty-one percent of workers said they put up with a noisy workplace for an average of almost nine consecutive months. Most were men with an average age of 40, tended to weigh more and smoke more -- both risk factors for heart disease -- than those who work in quieter places.

The study, published online in Occupational and Environmental Medicine, finds workers in the noisy workplaces were between two to three times more likely to have serious heart problems compared to their peers in quiet workplaces.

The blood tests of the workers who worked in nosier places, did not indicate particularly high levels of cholesterol or inflammatory proteins -- both risk factors for heart disease -- but diastolic blood pressure, was higher than normal, a condition known as isolated diastolic hypertension, an independent predictor of serious heart problems.