Risk factors for work-related musculoskeletal disorders in an aluminum smelter

A cross-sectional study of selected jobs in an aluminum smelter was conducted to assess the prevalence of work-related musculoskeletal disorders (WMDs), and to estimate their association with physical and psychosocial characteristics of the jobs. A structured interview and physical exam were used to assess the musculoskeletal health status of the participants, and a self-administered questionnaire was used to assess the psychosocial factors. Observational job analysis was conducted to evaluate 37 potential physical risk factors. Complete data were available for 104 subjects. The prevalence of WMDs on interview and physical exam were 0.8%, 14.9%, 11.6%, 14.9%, and 17.4% for the neck, shoulder, elbow/forearm, hand/wrist, and low back regions, respectively. Unconditional multiple logistic regression was used to model the relationship between physical and psychosocial factors and health status. Years of forearm twisting were found to be a significant predictor for hand/wrist disorders on interview (OR = 17, 95% CI = 2.9-106); for elbow/forearm disorders on physical exam and interview (OR = 37, 95% CI = 3.0-470); and for shoulder disorders on interview (OR = 92, 95% CI = 7.3-infinity) and on interview and physical exam (OR = 46, 95% CI = 3.8-550). Low decision latitude was also found to be significant for the shoulder on interview (OR = 4.5, 95% CI = 1.3-16). High job satisfaction (OR = 5.9, 95% CI = 1.4-25) and low social support (OR = 5.3, 95% CI = 1.3-22) were associated with low back pain report on interview; only high job satisfaction (OR = 5.3, 95% CI = 1.1-26) was associated with low back pain on both interview and physical exam.