Cancer risk among professional inshore divers in Norway.

BACKGROUND Professional divers are exposed to physiological effects of increased ambient pressure and may be exposed to hazards like carcinogens in polluted breathing gas and water. Consequences in terms of adverse health effects and mortality have been debated for many years. AIM The aim of this study was to compare the risk of cancer in Norwegian professional divers to that of the general population. MATERIALS AND METHODS All professional divers born 1950-1990 and registered by compulsory notification in The Norwegian Labour Inspection Authority's registry of divers were included and grouped according to the type of diving certificate. By August 2010, 5,526 male divers were identified. The rest of the male population born in the same period (1,591,243) was used as referents. The Cancer Registry of Norway, based on compulsory notification of all diagnosed malignancies, was linked to the Diver Registry. RESULTS A higher risk of cancer, OR 1.54 (CI 1.21-1.96), was observed among fully certified divers compared to the referents. No excess risk was observed for professional divers with limited certificate. CONCLUSIONS Norwegian fully certified divers had higher risk of cancer compared to the Norwegian male population. Based on small numbers, the higher risks among divers within subgroups of cancer sites should be interpreted with care.