WORK-RELATED MUSCULOSKELETAL DISORDERS AND ERGONOMIC STRESSORS IN THESOUTH-AFRICAN WORKFORCE

Objectives-The main objective of this study was to investigate exposur e-response relations between adverse musculoskeletal outcomes and ergo nomic exposure variables. Methods-A cross sectional analytical study w as conducted in 11 factories from seven sectors of manufacturing indus try in South Africa. Exposure to workplace ergonomic stressors was ass essed in factory floor jobs (n = 46) with a simple low technology obse rvational model. Repetition, force, static posture, dynamic movement, and other job exposures were measured. Data of adverse musculoskeletal outcome and data on potential confounders and effect modifiers were o btained from subjects (n = 401) randomly sampled from each job categor y with a questionnaire given by interviewers. Results-High prevalences of regional musculoskeletal pain were found with substantial variabil ity between industries. Sex was the only individual risk factor (after adjustment for potential confounders and effect modifiers) that was s ignificantly associated with regional pain. Ergonomic exposures in the workplace were significantly associated with musculoskeletal pain of the neck and shoulders odds ratio (OR) 5.38 (95% confidence interval ( 95% CI) 1.16 to 25.0) for repetition, and OR 3.91 (95% CI 1.11 to 13.7 ) for seated compared with standing work; pain of the wrists and hands OR 10.2 (95% CI 1.39 to 75.6) for high summed score of dynamic postur es of the wrist). Conclusions-This study indicates good predictive abi lity to reduce ergonomic stress with the exposure model, simple survei llance methods, and educational programmes in the workplace. Further s tudy on sampling strategies and refinement of dimensions of ergonomic stressors are needed.