Exposure to Polychlorinated Dioxins and Furans (PCDD/F) and Mortality in Cohort of Workers From an Herbicide-Producing Plant in Hamburg, Federal Republic of Germany

American Journal of Epidemiology 1995; 142:1165-75

Dieter Flesch-Janys, Jurgen Berger, Petra Gurn, Alfred Manz, Sibylle Nagel, Hiltraud Waltsgott, and James H. Dwyer

Abstract

The relation between mortality (all cause: cancer, cardiovascular diseases, ischemic heart diseases, and exposure to polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) was investigated in a retrospective cohort study. The cohort consisted of 1189 male workers in a chemical plant in Hamburg, Federal Republic of Germany, who had produced phenoxy herbicides, chlorophenols, and other herbicides and insecticides known to be contaminated with 2,3,7,8 - tetrachlorodibenzo-p-dioxin and other, higher chlorinated dioxins and and furans. The authors reported previously on cancer mortality in this cohort for the follow-up period 1952-1989. The current study covers the years 1092-1992 and investigated the relation of PCDD/F exposure to mortality using a quantitative estimate of PCDD/F exposure for the whole cohort derived from blood and adipose tissue in the estimation of relative risks (RRs) using year of birth stratified Cox regression. An unexposed cohort of highest relative risk was observed for the highest 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) decile (RR=2.43, 95% confidence interval (CI) 1.80-3.29). Cancer mortality and mortality due to ischemic heart diseases showed a dose-dependent relation with TCDD and all PCDD/F combined. The highest relative risks for cancer (RR=3.30, 95% CI 2.05-5.31) and ischemic heart diseases (RR=2.48, 95% CI 1.32 to 4.66) were observed in the highest PCDD/F exposure group. The pattern of effects and tests for trend were similar when the lowest exposure group within the chemical worker cohort served as the reference, but the relative risks were smaller and the confidence intervals were larger. Potential confounding exposures complicate the interpretation of the internal comparison. These findings indicate a strong dose-dependent relation between mortality due to cancer or ischemic heart diseases and exposure to polychlorinated dioxins and furans.