Cross-sectional study of the relationship between repetitive work and the prevalence of upper limb musculoskeletal disorders

Background This study examined the relationship of repetitive work and othe r physical stressors to prevalence of upper limb discomfort, tendinitis, an d carpal tunnel syndrome. Methods Three hundred fifty-two workers from three companies participated. Job exposure levels for repetition and other physical stressors were quanti fied using an observational rating technique. Ergonomic exposures were rate d on a 10-point scale, where 0 corresponded to no stress and 10 corresponde d to maximum stress. Job selection was based on repetition (three categorie s: high, medium, and low) to ensure a wide range of exposures. Physical eva luations on all participating workers were performed by medical professiona ls and included a self-administered questionnaire, physical exam, and limit ed electrodiagnostic testing. Results Repetitiveness of work was found to be significantly associated wit h prevalence of reported discomfort in the wrist, hand or fingers (odds rat io (OR) = 1.17 per unit of repetition; OR = 2.45 for high vs. low repetitio n), tendinitis in the distal upper extremity (OR = 1.23 per unit of repetit ion; OR = 3.23 for high vs. low repetition), and symptoms consistent with c arpal tunnel syndrome (OR = 1.16 per unit of repetition; OR = 2.32 for high vs. low repetition). An association was also found between repetitiveness of work and carpal tunnel syndrome, indicated by the combination of positiv e electrodiagnostic results and symptoms consistent with carpal tunnel synd rome (OR = 1.22 per unit of repetition; OR = 3.11 for high vs, low repetiti on). Conclusions These findings indicate that repetitive work is related to uppe r limb discomfort, tendinitis, and carpal tunnel syndrome in workers. Furth er research with a wider range of exposures is needed to evaluate the effec ts of other physical stresses alone and in combination. Am. J. Ind. Med. 36 :248-259, 1999. (C) 1999 Wiley-Liss, Inc.