Does the association between musculoskeletal pain and sickness absence due to musculoskeletal diagnoses depend on biomechanical working conditions?

AIM: To investigate single-site and multi-site musculoskeletal pain as predictors of future sickness absence due to musculoskeletal disorders (MSD) among blue-collar employees in food industry, and to study to what extent this relationship depends on physical loading at work.
METHODS: Survey responses of 901 employees on working conditions and musculoskeletal pain during the past week were linked to their future sickness absence records obtained from the personnel register of a food industry company. Negative binomial regression models were computed to determine associations of pain in one and in multi-site with the number of sickness absence days due to MSD during a four-year follow-up. Analyses were made in the whole cohort and stratified by the occurrence of repetitive movements and awkward postures (low/high).
RESULTS: Multi-site pain occurred among 59 % in the total cohort and predicted sickness absence with a rate ratio of 1.48 [95 % confidence interval (CI) 1.21-1.80], adjusted for age, gender, biomechanical and psychosocial working conditions, body mass index and physical exercise. Similar associations were seen in the sub-cohorts with a low occurrence of repetitive movements (RR 2.18, CI 1.69-2.80) and awkward postures (RR 1.78, CI 1.39-2.28), but not in the sub-cohorts with a high occurrence of these exposure. Single-site pain was not predictive of sickness absence.
CONCLUSIONS: A very high level of sickness absence in biomechanically strenuous work was found. Multi-site pain predicted sickness absence due to MSD among the employees with low exposure, but not among those with high exposure.