Surveillance program of neck and upper limb musculoskeletal disorders: assessment over a 4 year period in a large company.

OBJECTIVE: A company-wide surveillance program for musculoskeletal disorders (MSDs) based on the assessment of health and risk factors was implemented between 1996 and 2000 in a large shoe factory. The study aimed to compare the results of the surveillance program in 1996 and 1997 with the occurrence of MSDs in 2000.

METHODS: A health and ergonomic assessment of workstations was performed for 253 workers in 1996. Of these, 166 were examined again in both 1997 and 2000. A set of criteria was used to predict whether or not a job category could be predicted to have a potentially high risk of MSDs in 1996 and 1997 and the results were compared with the incidence rate of MSDs in the job category in 2000.

RESULTS: The criteria based on prevalence data in 1996 were unable to detect the job categories characterized by the occurrence of MSDs in 2000. The criterion based on an incidence rate >1% in 1997 was sensitive and specific. The agreement between the ranking of the job categories according to incidence rate of MSDs in 1997 and 2000 was good (rho=0.57, P=0.11). Agreement of the prediction based on ergonomic exposure was lower than that based on incidence data.

CONCLUSION: The efficacy of the surveillance program to predict on a collective basis the job categories in which numerous cases of MSDs occurred in 2000 depended on the decision criteria used. The criteria based on the incidence of MSDs were more reliable to predict the risk of MSDs than those based on prevalence data or on exposure assessment. Because exposure assessment plays a greater role in determining the priorities for ergonomic intervention, surveillance of health and exposure must nevertheless be combined to predict the risk of MSDs in the plant in the short and middle terms.