Health survey of former workers in a Norwegian coke plant: Part 2. Cancer incidence and cause specific mortality.

Abstract

OBJECTIVES: A Norwegian coke plant that operated from 1964 to 1988 was investigated to ascertain whether the male workers in this plant had increased morbidities of cancer or increased mortality from specific causes, particularly associated with specific exposures at the coke plant. METHODS: Personal data on all the employees of the plant were obtained from the plant's archives. With additional data from the Norwegian Bureau of Statistics we identified 888 male former workers at the plant. Causes of death were obtained from the Norwegian Bureau of Statistics, and cancer diagnoses from the Norwegian Cancer Registry. The results were compared with national averages adjusted for age. Specific exposures were estimated with records of actual measurements done at the plant and interviews with former workers at the plant. RESULTS: A significant excess of stomach cancer (standardised incidence ratio (SIR) 2.22, 95% confidence interval (95% CI) 1.01 to 4.21) was found. Mortality from ischaemic heart disease and sudden death was positively associated with work in areas which entailed peak exposures to CO. When considering work in such areas the past 3 years before death, the association was significant (p = 0.01). The last result is based on only two deaths. CONCLUSIONS: Considering the short follow up time and the small size of the cohort the results should be interpreted with a certain caution. The positive results would justify a re-examination of the cohort at a later date.