Aching backs and shoulders taking a toll

Washington -- Treatment for such common musculoskeletal disorders as rotator cuff tears, carpal tunnel syndrome or low back pain can be lengthy and costly -- making prevention the better option, said researchers at a recent conference of the American College of Occupational and Environmental Medicine.

But a review of the best intervention studies to reduce such injury in work settings revealed few winning strategies. For example, there is little evidence that wearing a back belt, typing on an ergonomically correct keyboard or providing health education results in much improvement in the rate of injuries, said presenters at the group's recent meeting, "Research to Practice to Policy," held in Washington, D.C., in early May.

On the other hand, stretching and strength-building exercise programs might help some workers in manufacturing jobs, and wearing the appropriate glasses and having support for the forearms could help computer users, presenters said.

There is no doubt that musculoskeletal disorders are taking a toll on the nation's health. They account for nearly 70 million physician office visits in the United States each year, according to a 2000 report by the National Academies. And they are expensive. Treatment for one rotator cuff case tallied $24,600, said Barbara Silverstein, PhD, MPH, research director for Washington state's Safety and Health Assessment and Research for Prevention program, or SHARP.

What's more, physicians should be prepared to see even more shoulder injuries as damaged rotator cuffs and related shoulder disorders appear to be on the upswing, even as cases of carpal tunnel syndrome decline, conference presenters said.

There is a likelihood that the nation's aging population could be fueling that increase because advancing age, rather than participation in sports, as is commonly thought, is strongly associated with shoulder disorders, said Kurt Hegmann, MD, MPH, research associate professor at the University of Utah. That the frequency climbs with age is true for men and women, he said.

One possible reason for this increase is the substantially lower blood supply that flows into the tendons of older people, Dr. Hegmann said. Studies have found that older tendons had only 41% of the blood supply of younger tendons.

What helps?

While very little is known about additional risk factors beyond the well-recognized workplace hazards faced by those who perform repetitive motions at keyboards or on assembly lines, or by those who do heavy lifting, a few studies have singled out smoking and obesity as factors that increase risk, Dr. Hegmann said.

The link between a population that is getting older and heavier is expected to be more fully explored this fall in a Seattle conference sponsored by Washington state's Dept. of Labor, the University of Washington's School of Public Health and the National Institute for Occupational Safety and Health, Dr. Silverstein said.

Meanwhile, she examined numerous recently published studies on musculoskeletal disorders for insights regarding prevention of those injuries.

So far, the evidence strongly supports the effectiveness of exercise, Dr. Silverstein said.

On the other hand, no positive effects were found in the five studies that examined the effects of health education in the workplace. "I think a lot of us do health education and believe it is going to have a lasting effect on reducing injuries and illnesses," Dr. Silverstein said. But the research shows that education alone isn't enough to prevent musculoskeletal injuries, she said.

"I think we can put the back belt issue to bed," she added, noting that a review of virtually all of the studies turned up no positive evidence that belts supporting the lower back prevent back injuries.

But studies of health care workers found some benefit to exercise and training in reducing low back pain. There also was a lower percentage of insurance claims for low back pain when lifting equipment was used in hospitals. Studies found that "zero-lift" policies at nursing homes and hospitals appear to be effective.

Among computer users, studies on the effectiveness of participatory training found symptom reduction among younger workers but not older ones.

Studies also showed that the use of software that signals when to take a break from the computer did not result in any improvements in injury rates.

There was also no clear evidence that wrist braces and ergonomic keyboards were effective at preventing carpal tunnel syndrome, and there was only limited evidence that ultrasound, oral steroids and yoga were effective therapies. But wearing a splint at night did seem to relieve some pain.

While many of the best studies have yet to be done, Dr. Silverstein warned that workplace changes are occurring too fast to allow physicians and others the luxury of waiting for them to be published. Instead, understand the caveats carried by many of the studies and choose the most appropriate on which to base care, she advised.