Historical cohort study of 10 109 men in the North American vinyl chlorideindustry, 1942-72: update of cancer mortality to 31 December 1995

Objectives-To update and assess mortality from neoplasms to 31 December 199 5 among 10 109 men employed in a job exposed to vinyl chloride for at least 1 year between 1942 and 1972 at any of 37 North American factories. Previo us analyses indicated associations between employment in vinyl production a nd increased mortality risk from cancers of the liver and biliary tract, du e to increased mortality from angiosarcoma of the liver, and brain cancer. Methods-Standardised mortality ratio (SMR) analyses, overall and stratified by several work related variables, were conducted with United States and s tate reference rates. Cox's proportional hazards models and stratified log rank tests were used to further assess occupational factors. Results-895 of 3191 deaths (28%) were from malignant neoplasms, 505 since t he previous update to the end of 1982. Mortality from all causes showed a d eficit (SMR 83, 95% confidence interval (95% CI) 80 to 86), whereas mortali ty from all cancers combined was similar to state referent rates. Mortality from cancers of the liver and biliary tract was clearly increased (SMR 359 , 95% CI 284 to 446). Modest excesses of brain cancer (SMR 142, 95% CI 100 to 197) and cancer of connective and soft tissue (SMR 270, 95% CI 139 to 47 2) were found. Stratified SMR and Cox's proportional hazard analyses suppor ted associations with age at first exposure, duration of exposure, and year of first exposure for cancers of the liver and soft tissues, but not the b rain. Conclusions-Excess mortality risk from cancer of the liver and biliary trac t, largely due to angiosarcoma, continues. Risk of mortality from brain can cer has attenuated, but its relation with exposure to vinyl chloride remain s unclear. A potentially work related excess of deaths from cancer of conne ctive and soft tissue was found for the first time, but was based on few ca ncers of assorted histology.