Suggested excess of occupational cancers in Norwegian offshore workers: preliminary results from the Cancer Registry Offshore Cohort

Abstract

The aim of this communication was to report the overall incidence of cancer in a cohort of male Norwegian offshore oil workers. The Offshore Cohort was comprised of >25,000 men who were employed at installations in the North Sea in the period 1965-1999, and who responded to a questionnaire that included work history offshore, other occupational experience, education, leisure-time activities, and lifestyle factors. Calculating standardized incidence ratios (SIR), we compared the number of prospective incident cancers diagnosed between 1999 and 2005 with those expected for age-, gender- and period-specific rates in the general Norwegian population. The overall cancer incidence did not differ from that of the reference population [SIR=1.0, 95% -confidence interval (95% CI) 1.0-1.1, N=695]. There were indications of excess risks of acute myeloid leukemia (SIR=2.0, 95% CI 1.0-3.7) and cancer of the pleura (SIR=2.2, 95% CI 0.9-4.6). No data on occupational history was used in these preliminary analyses. The cohort was relatively young and an extended observation period would be important for in-depth analyses. The suggested excess of leukemia and cancer of the pleura may be linked to occupational exposure during employment offshore; this issue needs to be addressed in further studies.