Cancer incidence in Thyborøn-Harboøre, Denmark: a cohort study from an industrially contaminated site

Abstract

In a fishing community Thyborøn-Harboøre on the Danish West coast, a chemical factory polluted air, sea, and ground with > 100 xenobiotic compounds. We investigated cancer incidence in the community. A historical cohort was identified from the Central Population Register and followed for cancer incidence in the Danish Cancer Register including inhabitants from 1968–1970 at height of pollution, and newcomers in 1990–2006 after pollution control. Two fishing communities without pollution, Holmsland and Hanstholm, were referent cohorts. We calculated rate ratios (RR) and 95% confidence intervals (CI). In 1968–1970, 4914 persons lived in Thyborøn-Harboøre, and 9537 persons in Holmsland-Hanstholm. Thyborøn-Harboøre had a statistically significant excess cancer incidence compared with Holmsland-Hanstholm; RR 1.20 (95% CI 1.11–1.29) deriving from kidney and bladder cancer; stomach and lung cancer in men, and colorectal cancer in women. In 1990–2006, 2933 persons came to live in Thyborøn-Harboøre. Their cancer incidence was the same as for newcomers to Holmsland-Hanstholm; RR 1.07 (95% CI 0.88–1.30). Persons in Thyborøn-Harboøre at height of chemical pollution had a cancer risk 20% above persons living in non-polluted fishing communities with a pattern unlikely to be attributable to life style. The study suggested that chemical pollution may have affected cancer risk.