Retrospective cohort study of two plants in the Swedish rubber industry

A cohort of 13,114 workers employed during 1930-1975 in two Swedish plants producing tires and industrial rubber goods was investigated with regard to cancer mortality and cancer incidence. Separate analyses were performed on the following subgroups of the cohort: mixers/weighers, other production workers, and white-collar employees. For all causes of death no increase of risk was observed in the population as a whole. Mixers/weighers showed however an increased overall standardized mortality ratio. The pattern of causes of death was not changed in the total cohort. An increased risk to die from liver cancer (risk ratio 4.12) and pancreatic cancer (risk ratio 2.70) was, however, observed for the category other production workers. An increased risk of death from tumors of the respiratory organs was also observed for the categories other production workers (risk ratio 1.89) and white-collar employees (risk ratio 2.63). For tumors in the urinary bladder (risk ratio 2.50) and for ischemic heart diseases (risk ratio 1.27) the death risk was elevated for the category other production workers. The cancer morbidity pattern showed an increase in malignant melanomas (risk ratio 2.50) for the category other production workers and for lung cancer (risk ratio 2.09), as well as for tumors in the nervous system (risk ratio 3.18) for white-collar employees.