Hospital contacts for injuries and musculoskeletal diseases among seafarers and fishermen with focus on carpal tunnel syndrome and rotator cuff syndrome- A population-based cohort study Running title: Musculoskeletal diseases among seamen and fishermen Words

Background: Only a few studies have addressed seamen’s health although they have dangerous working conditions. We studied musculoskeletal diseases among fishermen and seafarers with focus on carpal tunnel syndrome and rotator cuff syndrome. Methods: Cohorts of all male Danish seafarers 1986-1998 and fishermen 1964-1998. We calculated standardised incidence ratios (SIR) and compared SIRs for two employment time periods, 1994 and 1999, using rates for the entire Danish workforce as a reference. Results: Among fishermen, we found high SIRs for knee arthrosis, thoraco-lumbar disc disorders, shoulder diseases and injuries. The SIR was augmented for injuries between the two time periods. Statistically significant SIRs above 200 were seen for both rotator cuff syndrome and carpal tunnel syndrome. The SIRs for injuries, burns and carpal tunnel syndrome were high for nonofficers, whereas officers had low SIRs. A sub-analysis revealed that the highest risk for carpal tunnel syndrome was found among male non-officers working as deck crew, SIR 233 (95% CI: 166-317) based on 40 cases (data not shown). Conclusions: Both fishermen and non-officers have increased SIRs for injuries and fishermen also for musculoskeletal diseases. Our findings suggest an association between the incidence of rotator cuff syndrome and carpal tunnel syndrome and work within fishery. Whether these diseases are caused by physically demanding repetitive work, by injuries or lifestyle related diseases among fishermen needs to be explored in studies with more detailed exposure data and better control of confounding.