An ongoing debate in Washington grew even more contentious recently when the Occupational Safety and Health Administration instituted rules to reduce musculoskeletal disorders (MSDs) in the workplace. Proponents argue that workers need protection from job-related disorders of the lower back and shoulders, arms, and hands. But opponents - including some industry leaders and policy makers - point out that implementation will be costly. Moreover, critics have questioned whether sufficient scientific evidence supports the regulations, which officially took effect in January.

When a committee of the National Research Council and Institute of Medicine recently released a report on MSDs, it quickly became grist for both sides of the debate, even though the report - a rigorous two-year review of the scientific evidence - did not examine the regulations. But science rarely gives an all-or-nothing picture, and the danger in polarizing scientific work is that policy makers will miss the complexities of the issue. The nation simply cannot afford to do that, especially since these disorders affect about 1 million workers annually and cost between $45 billion and $54 billion in compensation expenditures, lost wages, and decreased productivity.

To be sure, there are many complexities surrounding MSDs. Nevertheless, the scientific evidence plainly indicates that particular jobs and working conditions - such as heavy lifting, repetitive and forceful motions, and stressful work environments - are risk factors for these disorders, although the relationship between them is complicated. Other factors like age, gender, lifestyle, and various psychosocial stresses also appear to play a role.

Clearly, some workers have a higher risk of contracting MSDs than others. Among men, those who work as construction laborers, carpenters, and operators of industrial truck or tractor equipment are at the highest risk. For women, the highest-risk jobs are in nursing or nursing support, and in domestic or commercial cleaning and janitorial work. Many of these jobs require workers to manually lift materials, frequently bend and twist their bodies, or experience whole-body vibration from motor vehicles - all risk factors for developing MSDs.

MSDs also affect workers in many other industries - from agriculture, manufacturing, and mining to finance, the service sector, and transportation. A rapid work pace, monotonous work, low job satisfaction, little decision-making power, and high levels of job stress also may play a role in back disorders. Such psychosocial factors stem from organizational and social aspects of work, and they can affect how employees view themselves in relation to the workplace. For disorders that affect the shoulders, arms, wrists, and hands, important risk factors are repetition, force, and vibration, as are highly demanding and stressful environments.

The big question that many employers and employees want answered is whether the pain and symptoms of these disorders can be prevented. The answer - based on the scientific literature - is "yes," but there is no one-size-fits-all program that every business can adopt or that applies to every worker. Successful programs can be found in a variety of job settings, and they take into account procedures, equipment, and characteristics specific to the organization. Examples include offering exercise programs for employees, providing ergonomically designed office equipment, or retooling procedures to reduce repetition. But for these efforts to be successful, they must be tailored to the individual workplace, and a high level of commitment is needed from both employers and employees.

Some think that as work changes in the future and the nation moves toward a service-based economy, the risk factors for MSDs will diminish. But even so, manual labor will remain important - particularly in light of the additional large distribution centers required for rapid movement of the many products demanded through e-commerce. Furthermore, the work force itself is changing. More women and older workers are entering the labor market, a trend that may call for modifications of some work demands that might increase the risks of MSDs among these groups.

Science may not have the answers that some businesses, employers, or policy makers want to hear, but the time has come to listen to what is known about MSDs and to use that knowledge to make wise decisions in the years to come.