Occupational factors related to shoulder pain and disability

Objectives--To determine, in a population based study, the influence of occupational factors on the occurrence of shoulder pain and disability. Methods--A random sample of patients was selected from the register of a general practice in the Greater Manchester area of the United Kingdom. Information was collected by a posted questionnaire with specific enquiries about symptoms in the shoulder region and related disability. A lifetime occupational history was obtained including physical exposures, working conditions, and psychosocial aspects of each workplace. Analysis has been conducted as a case-control study, comparing occupational exposures at the time of onset of symptoms in those with shoulder pain and disability with corresponding occupational exposures in those without shoulder pain and disability. Results--An increased risk of shoulder pain and disability in men was associated with carrying weights on one shoulder (relative risk (RR) 5.5, 95% confidence interval (95% CI) 1.8 to 17), whereas those who reported working with hands above shoulder level, using wrists or arms in a repetitive way, or stretching down to reach below knee level had about twice the risk of shoulder pain and disability. Men working frequently in very cold or damp conditions had a fourfold and sixfold risk respectively of shoulder pain and disability. Reporting of shoulder pain and disability was also more common among men and women who reported that their work caused a lot of stress (RR 1.9, 95% CI 0.9 to 4.1) or was very monotonous (RR 2.7, 95% CI 1.3 to 5.4). The relations between physical exposures, working conditions, and psychosocial factors were independent. Conclusions--This population based study has shown that physical activities carried out at work, the physical conditions under which the work is conducted, psychosocial aspects of work, or the working environment are all independently related to the occurrence of shoulder symptoms and disability, emphasising the multifactorial nature of this condition.