Psychosocial factors and shoulder symptom development among workers

Background Shoulder injuries are a common cause of pain and discomfort. Many work-related factors have been associated with the onset of shoulder symptoms. The psychosocial concepts in the demand-control model have been studied in association with musculoskeletal symptoms but with heterogeneous findings. The purpose of this study was to assess the relationship between the psychosocial concepts of the demand-control model and the incidence of shoulder symptoms in a working population. Methods After following 424 subjects for approximately 1 year, 85 incident cases were identified from self-reported data. Cox proportional hazards modeling was used to assess the associations between shoulder symptoms and demand-control model quadrants. Results Cases were more likely to be female and report other upper extremity symptoms at baseline (P < 0.05). From the hazard models, being in either a passive or high strain job quadrant was associated with the incidence of shoulder symptoms. Hazard ratios were 2.17, 95% CI 1.02-4.66 and 2.19, 95% CI 1.08-4.42, respectively. Conclusions Using self-reporting to determine demand-control quadrants was successful in identifying subjects at risk of developing work-related shoulder symptoms. Research is needed to determine if this relationship holds with clinically diagnosed shoulder and other upper extremity musculoskeletal disorders. This may be part of a simple tool for assessing risk of developing these UEMSDs. Am. J. Ind. Med. 52:57-68, 2009. Caroline K. Smith MPH1 * Barbara A. Silverstein PhD MPH CPE1 Z. Joyce Fan PhD1 Stephen Bao PhD CPE1 Peter W. Johnson PhD2 [1]Safety & Health Assessment and Research for Prevention (SHARP), Washington State Department of Labor & Industries, Olympia, Washington;[2]Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington