Sunday, November 25, 2007

Traffic noise and heart disease linked in study

The Wisconsin Department of Transportation is proposing to build a bigger, noisier North-South I-94 closer to Milwaukee homes. From The Montreal Gazette:

A landmark study that followed 27,000 sawmill workers in British Columbia over a 45-year period shows a direct link between occupational noise measured at 85 decibels or higher, and heart disease.

But scientists have noted similar effects at 65 decibels or lower - levels that are considered safe - from a steady stream of noise at home or at work, like the din of traffic or construction, or the bustle of a busy office. (Emphasis mine)

"Increasing noise exposure means increasing heart attacks - fatal heart attacks. There are consistent (study) results showing this association," the study's lead author, Hugh W. Davies of the University of British Columbia, said at a public health conference held in Montreal.

"We've done little to reduce noise at work. Instead, we give people earplugs." But earplugs aren't effective against heart disease, he said.

"There's no economic pressure to reduce noise in the workplace. And from a safety point of view ... there's the old saying, 'Ears don't bleed.' " Noise can increase the levels of stress hormones like cortisol, adrenaline and noradrenalin in the body, even during sleep.

The greater the exposure to noise, the greater the stress levels that can lead to heart failure, stroke, high blood pressure and immune-system problems.

The noise of modern life could be to blame for thousands of deaths from coronary heart disease, Davies said.

New data from the World Health Organization also show that chronic noise exposure, including to daytime traffic, triggers heart disease.

"The Europeans are way ahead of of us" in dealing with noise as a major public health issue, Davies said.

The European Union issued a directive this year requiring European cities with populations exceeding 250,000 to create digital noise maps depicting areas of highest traffic noise and volume.

Such maps are tools for planners of homes, hospitals and schools, as well as for people seeking to live away from busy intersections, truck stops or flight patterns.

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