Incidence of shoulder pain in repetitive work.

AIMS To determine the predictiveness of personal and occupational factors for the onset of shoulder pain in occupations requiring repetitive work. METHODS A sample of 598 workers in five activity sectors completed a self administered questionnaire in 1993-94 and again three years later. Both questionnaires included questions about shoulder pain. The associations between various factors at baseline and subsequent shoulder pain were studied among subjects free from shoulder pain at baseline. RESULTS The incidence of shoulder pain was associated with several independent risk factors: depressive symptoms, low level of job control, and biomechanical constraints. After adjustment for other risk factors, the presence of depressive symptoms predicted occurrence of shoulder pain. A low level of job control was also associated with the onset of shoulder pain in both sexes. For men, repetitive use of a tool was a strong predictor, while the two most important biomechanical risk factors for women were use of vibrating tools and working with arms above shoulder level. CONCLUSION This study used a longitudinal approach to examine different sets of risk factors for shoulder pain simultaneously. The results confirm the role of several biomechanical constraints. Psychological symptoms and a low level of job control also play a role.