EXPOSURE TO DIOXIN AND NONNEOPLASTIC MORTALITY IN THE EXPANDED IARC INTERNATIONAL COHORT STUDY OF PHENOXY HERBICIDE AND CHLOROPHENOL PRODUCTION WORKERS AND SPRAYERS

The authors studied noncancer mortality among phenoxyacid herbicide an d chlorophenol production workers and sprayers included in an internat ional study comprising 36 cohorts from 12 countries followed from 1939 to 1992. Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin or higher ch lorinated dioxins (TCDD/HCD) was discerned from job records and compan y questionnaires with validation by biologic and environmental measure s. Standard mortality ratio analyses suggested a moderate healthy work er effect for all circulatory diseases, especially ischemic heart dise ase, among both those exposed and those not exposed to TCDD/HCD. In Po isson regression analyses, exposure to TCDD/HCD was not associated wit h increased mortality from cerebrovascular disease. However, an increa sed risk for circulatory disease, especially ischemic heart disease (r ate ratio [RR] 1.67, 95% confidence interval [CI] 1.23-2.26) and possi bly diabetes (RR 2.25, 95% CI 0.53-9.50), was present among TCDD/HCD-e xposed workers. Risks tended to be higher 10 to 19 years after first e xposure and for those exposed for a duration of 10 to 19 years. Mortal ity from suicide was comparable to that for the general population for all workers exposed to herbicides or chlorophenols and was associated with short latency and duration of exposure. More refined investigati ons of the ischemic heart disease and TCDD/HCD exposure association ar e warranted.