Hospital contacts for injuries and musculoskeletal diseases among seamen and fishermen - A population-based cohort study Running title: Musculoskeletal diseases among seamen and fishermen Words

Background: We studied musculoskeletal diseases (MSD) and injuries among fishermen and seamen with focus on low back disorders, carpal tunnel syndrome (CTS), rotator cuff syndrome and arthrosis. Methods: Cohorts of all male Danish seamen (officers and nonofficers) and fishermen employed 1994 and 1999 with at least six months employment history were linked to the Occupational Hospitalisation Register. We calculated standardised incidence ratios (SIR) for the two time periods, using rates for the entire Danish workforce as a reference. Results: Among fishermen, we found high SIRs for knee arthrosis, thoracolumbar disc disorders, injuries and statistically significant SIRs above 200 were seen for both rotator cuff syndrome and CTS. The SIR was augmented for injuries and reduced for hip arthrosis between the two time periods. The SIRs for injuries and CTS were high for nonofficers. A sub-analysis revealed that the highest risk for CTS was found among male nonofficers working as deck crew, SIR 233 (95% CI: 166-317) based on 40 cases. Among officers, the SIRs for injuries and MSDs were low. Short-term employments were common. None of the SIRs increased with increasing length of employment. Conclusions: Both fishermen and non-officers have high SIRs for injuries and fishermen also for MSD. Only the SIR for injuries among fishermen was augmented between 1994 and 1999. Our findings suggest an association between the incidence of rotator cuff syndrome and CTS and work within fishery. Long-term cumulative effects of employment were not shown for any of the disease outcomes. Other conditions may play a role.