Cancer incidence among merchant seafarers: an extended follow-up of a Danish cohort

ObjectivesWhile maritime safety generally has improved dramatically over the last century, modern seafarers are still faced with numerous occupational hazards potentially affecting their risk of chronic diseases such as cancer. The aim of this study is to offer updated information on the incidence of specific cancers among both male and female seafarers.MethodsUsing records from the Danish Seafarer Registry, all seafarers employed on Danish ships during 1986–1999 were identified, resulting in a cohort of 33 084 men and 11 209 women. Information on vital status and cancer was linked to each member of the cohort from the Danish Civil Registration System and the Danish Cancer Registry using the unique Danish personal identification number. SIRs were estimated for specific cancers using national rates.ResultsThe overall incidence of cancer was increased for both male and female seafarers (SIR 1.19, 95% CI 1.15 to 1.23, and SIR 1.14, 95% CI 1.07 to 1.22) compared with the general population. This excess was primarily driven by increases in gastrointestinal, respiratory and genitourinary cancers. In addition, male seafarers working in areas with asbestos exposure showed significantly increased risk of mesothelioma. Finally, the male seafarers had an increased risk of lip cancer.ConclusionsThe majority of cancers among seafarers continue to be lifestyle-related. However, occupational exposure to asbestos and ultraviolet radiation seems to affect the cancer pattern among the male seafarers as well.