and cultural values, and (3) the physical and psychological characteristics of the individual. The most important of the latter include age, gender, body mass index, personal habits including smoking, comorbidities, and probably some aspects of genetically determined predispositions. In addition, physical activities away from the workplace may also cause musculoskeletal syndromes; the interaction of such factors with physical and psychosocial stresses in the workplace is a further consideration. The task herein is to evaluate the significance of the risk factors that result from work exposure while taking into account the different types of individual and non-work factors. The complexity of the problem is further increased because all of these factors interact and vary over time and from one situation to another. Research is needed to clarify such relationships, but research is complicated by the fact that estimates of incidence in the general population, as contrasted with the working population, are unreliable because the two overlap: more than 80 percent of the adult population is in the workforce.
The panel approached the complex of factors bearing on the risk of musculoskeletal injury in the work setting from a whole-person perspective, that is, from a point of view that does not isolate disorders of the low back and upper extremities from physical and psychosocial factors in the workplace, from the context of the overall texture of the worker's life, including social support systems and physical and psychosocial stresses outside the workplace, or from personal responses to pain and individual coping mechanisms (see Figure ES.1).
The size and complexity of the problem and the diversity of interests and perspectives—including those of medical and public policy professionals, behavioral researchers, ergonomists, large and small businesses, labor, and government agencies—have led to differing interpretations of the evidence regarding the work-relatedness of musculoskeletal disorders of the low back and upper extremities and the impact of interventions. As a result, Congress requested a study by the National Research Council and the Institute of Medicine covering the scientific literature on the causation and prevention of these disorders. The congressional request was presented in the form of seven questions, which are addressed in Appendix A of this report. The funding for the study was provided by the National Institute for Occupational Safety and Health (NIOSH) and by the National Institutes of Health (NIH).
The charge to the panel from NIOSH and NIH was to undertake a series of tasks that would lead to a detailed analysis of the complex set of factors contributing to the occurrence in the workplace of musculoskeletal