Increased risk of oesophageal adenocarcinoma among upstream petroleum workers

Abstract

Objectives: To investigate the risk of major cancer types with a particular focus on oesophageal cancer among male upstream petroleum workers offshore potentially exposed to various carcinogenic agents.

Methods: Using the Norwegian Registry of Employers and Employees, we included 24,765 male offshore workers registered from 1981 to 2003 and 283,002 male referents from the general working population matched by age and community of residence. The historical cohort was linked to the Cancer Registry of Norway and the Norwegian Cause of Death Registry.

Results: Male offshore workers had excess risk of oesophageal cancer (rate ratio (RR) = 2.6;95% confidence interval (CI) 1.4–4.8) compared with the general male working population. Only the adenocarcinoma type was significantly increased (RR 2.7;95% CI 1.0–7.0), and the increased risk was mainly ascribed to an increased risk among “upstream operators” (RR 4.3;95% CI 1.3–14.5). “Upstream operators” did not have significant excess of cancer of the respiratory system or colon or mortality from any of the lifestyle-related diseases investigated.

Conclusion: We found a four-fold excess risk of oesophageal adenocarcinoma among male workers assumed to have had the most extensive contact with different phases of crude oil. Due to the small number of cases, and a lack of detailed data on occupational exposure and lifestyle factors found to be associated with esophageal adenocarcinoma, the results must be interpreted with caution. Nevertheless, given the low risk of lifestyle-related cancers and causes of death in this working group, the results add to the observations in other low-powered studies on oesophageal cancer further suggesting that factors related to the petroleum stream or carcinogenic agents used in the production process might be associated with the risk of oesophageal adenocarcinoma.