Pathomechanisms of work-related musculoskeletal disorders: conceptual issues

Work-related musculoskeletal disorders (WRMSDs) by definition are a subset of musculoskeletal disorders (MSDs) that arise out of occupational exposures. While traditional exposure assessment techniques have proved to be successful in identifying ergonomic exposures that are epidemiologically linked to these disorders, some are troubled by the lack of one-to-one correspondence between specific occupational exposure profiles and specific MSDs. In the absence of more sophisticated hypotheses that might explain the occurrence of WRMSDs in a variety of exposure patterns, the aetiologic relationships may (again) be called into question. Another unanswered question is whether specific types of WRMSDs have qualitatively different exposure-response relationships. A clearer understanding of the underlying pathomechanisms associated with specific WRMSDs could help future researchers better determine how and when various occupational exposure profiles become pathogenic. Such knowledge could also be used to design exposure assessment tools to capture exposure information more relevant to the risk of WRMSDs. The main goals of this paper are to summarize several recently described pathomechanisms, most of which have been discussed primarily in clinical and experimental literature that might not be widely read by occupational health scientists. Suggestions are made as to how future research could evaluate whether these phenomena are relevant to the effects of physical exposures and the underlying disease processes of common WRMSDs.