A case-referent study of cancer mortality among sulfate mill workers in Sweden.

OBJECTIVES To investigate whether workers in Swedish sulfate mills have an increased risk of death from certain malignancies that have previously been linked to the pulping process. METHODS Subjects of the study (n=2480) were men aged 40-75 at death during 1960-89 in the parishes surrounding four sulfate mills. Exposure assessment was based on information from the personnel files in the mills- 35% of the subjects were recognised there, and work categories were created. RESULTS Among all sulfate mill workers, the odds ratio (OR) (90% confidence interval (90% CI)) for death from lung cancer was 1.6 (1.1 to 2.3), pleural mesotheliomas 9.5 (1.9 to 48), brain tumours 2.6 (1.2 to 5.3), and liver or biliary tract cancer 2.3 (1.0 to 5.2). There was an increased mortality from leukaemia among workers in the soda recovery plant (5.9 (2.6 to 13)) and bleaching plant and digester house (2.8 (1.0 to 7.5)). CONCLUSIONS Sulfate mill workers were at increased risk of dying from lung cancer and pleural mesotheliomas, probably due to exposure to asbestos. Increased risks of brain tumours and cancers of the liver or biliary tract were also found but the aetiology is not obvious.