Cancer in seamen with special reference to chemical health hazards

Abstract

Age-standardized cumulative cancer incidence ratios (SIRs) for different cancer sites and different categories of Swedish seamen 1971-1987 were calculated from data in the Swedish Cancer-Environment Register. All economically active Swedish men were used as reference group. The SIRs were increased for cancer sites related to alcohol and tobacco consumption, especially among catering personnel. The incidence of lung cancer among engine officers and ratings was more than twice as high as expected. This could only partly be explained by smoking habits. Exposure to asbestos and/or polycyclic aromatic hydrocarbons (PAH) may have contributed to the increased risk. There were 4 cases of pleural cancer among engine officers vs. 0.46 expected, indicating exposure to asbestos.In a cohort of men conscripted for compulsory military training in Sweden 1969-1970, those who became seamen had significantly increased relative risks for death of violent causes, early retirement, and for psychiatric diagnoses related and not related to alcohol and drug abuse. These outcomes seem partly due to selection, since 14 of 16 risk indicators at conscription 1969-1970 were more prevalent among seamen, but the results suggest that conditions intrinsic to seafaring also contributes to the high relative risks.In a nested case-referent study, seamen exposed to cargo vapours containing benzene and other hydrocarbons on chemical and product tankers had increased relative risks for non-Hodgkin's lymphoma and all lymphatic and haematopoietic malignancies combined, when compared to all Swedish seamen. There was also a positive dose-response relationship.Biomarkers of exposure, genotoxic and other biological effects of benzene and other hydrocarbons were investigated in three cross-sectional studies. Acute effects were reported by 85% of the deck crew exposed to cargo vapours, but no chronic health effects, or other biological effect could be linked to occupational exposure. Single-strand breaks in DNA in lymphocytes and 8-hydroxydeoxyguanosine (8OHdG) in urine increased over shift in workers exposed to benzene (about 0.3 mg/m3) from gasoline when compared with controls. There was a exposure-effect relationship for 8OHdG. Engine room personnel had increased urinary levels of 1-hydroxypyrene (1OHP), a biomarker for exposure to PAH, mainly due to skin exposure to PAH from oils.These studies show that seamen have an increased risk of cancer and other diseases, due to occupational exposures and lifestyle factors.