Women twice as likely as men to develop some musculoskeletal disorders

Women are at least twice as likely as men to develop some musculoskeletal disorders of the upper body.

That’s the finding of scientists at Ohio State University who re-analyzed data from 56 previous studies on the subject.

Musculoskeletal pain is an extremely common problem. In this age of fitness promotion, many people develop musculoskeletal disorders related to overuse of weak or improperly stretched muscles, tendons or ligaments. Strenuous daily vocational activities, such as lifting, bending, or prolonged typing, can cause musculoskeletal pain through constant stress on the musculoskeletal system.

As the population ages, more and more individuals complain of pain related to osteoarthritis, contracture, and degenerative disc disease. All of these disorders may interfere with a person's normal vocational and recreational activities.

This new work, though it did not yield specific incidence rates for different disorders, gives researchers a critical baseline for comparing gender differences in the prevalence of disorders of the neck, shoulders, arms, and hands.

Until now, some researchers suspected that women only appear to have a higher incidence of these disorders because they are more likely than men to admit that they are in pain and get treatment. Others thought the gender difference was due to a greater exposure to certain risk factors for women.

Delia Treaster, a former doctoral student at Ohio State, conducted this research with Deborah Burr, assistant professor of epidemiology and biometrics. They performed a statistical analysis of previous studies to remove factors that could have skewed the results either way. They described their findings in a recent issue of the journal Ergonomics.

When they accounted for factors such as a person’s age, occupation, and whether the person reported their disorder themselves or whether it was clinically diagnosed, they were surprised to find that the gender difference still remained.

“Any way you slice the data, women have a significantly higher prevalence –- anywhere from two to ten, even eleven times higher than men -- for many of these disorders,” Treaster said. “The question now is, why? Is it biomechanical, physiological, psychological, or what? Most likely, it is due to a combination of factors.”

Burr cautioned women to be aware that they could develop these disorders, especially as they grow older. “Women should talk to their doctors about it, and doctors should look out for it,” she said.

Musculoskeletal disorders (MSDs) affect the muscles, tendons, ligaments, and joints. One 1998 study found that 15 percent of the American working population suffered one or more MSDs, and that this rate could increase to 18 percent within the next 30 years.

Researchers believe that doing highly repetitive or physically stressful work can cause MSDs. There can be psychological and social factors as well. William Marras, a professor of industrial, welding, and systems engineering and director of the Biodynamics Laboratory at Ohio State, had previously linked high performance pressure and job dissatisfaction to low back pain, the most common MSD.

This latest study focused on upper-body disorders other than back pain, the highest-profile of which is carpal tunnel syndrome (CTS). For sufferers of CTS, a nerve in the wrist becomes irritated, causing pain and numbness in the hands.

As the Ohio State scientists reviewed studies from 13 countries, they found much data concerning CTS in the United States, while most European studies focused on shoulder and neck disorders.

“Now the pendulum is swinging the other way -- neck and shoulder pain is becoming a hot issue here, and European scientists are becoming interested in carpal tunnel,” Treaster said.

MSDs can be difficult to diagnose, she added. Doctors can perform clinical tests for CTS, but for neck and shoulder disorders “all you have to go on is whether someone is in pain, and pain is so subjective.”

The conventional wisdom is that men do physically demanding work such as heavy lifting that makes them more susceptible to back problems, while women do the fine, repetitive work that can lead to neck, shoulder, and wrist problems. But this new study showed that women were more likely than men to develop MSDs even when they have the same job.

To Treaster, the study underscores the need to prevent MSDs from happening in the first place. One way to do that is through better workplace design, equipment selection, and work practices.

“This is yet another gender difference that will have to be taken into account,” she said.

Treaster is a professional ergonomist currently helping the United States Post Office implement the ergonomics in its distribution centers. Burr has no immediate plans to continue this research, though she says she might like to further analyze the data and compute more detailed incidence rates for individual disorders.

http://www.osu.edu/