Cancer Mortality in Workers Exposed to Phenoxy Herbicides, Chlorophenols, and Dioxins

Authors

Manolis Kogevinas, Unit of Environmental Cancer Epidemiology, International Agency for Research on Cancer, Lyon, France
Heiko Becher, Division of Epidemiology, German Cancer Research Center, Heidelberg, Germany
Trevor Benn, Epidemiology and Medical Statistics Unit, Health and Safety Executive, Bootle, England, United Kingdom
Pier Alberto Bertazzi, Institute of Occupational Health, University of Milan, Milan, Italy
Paolo Boffetta, Unit of Environmental Cancer Epidemiology, International Agency for Research on Cancer, Lyon, France.
H. Bas Bueno-de-no-de-, Department of Chronic Disease and Environmental Epidemiology, National Institute of Public Health and the Environment, Bilthoven, The Netherlands
David Coggon, Medical Research Council Environmental Epidemiology Unit, Southampton, England, United Kingdom
Didier Colin, Unit of Environmental Cancer Epidemiology, International Agency for Research on Cancer, Lyon, France
Dieter Flesch-Janys, Medical Center for Chemical Workers' Health, Hamburg, Germany
Marilyn Fingerhut, Industrywide Studies Branch, National Institute of Occupational Safety and Health, Cincinnati, Ohio, United States
Lois Green, Health Services Department, Ontario Hydro, Toronto, Ontario, Canada
Timo Kauppinen, Department of Epidemiology and Biostatistics, Finnish Institute of Occupational Health, Helsinki, Finland
Margareta Littorin, Department of Occupational and Environmental Medicine, Lund University, Lund, Sweden
Elsebeth Lynge, Danish Cancer Society, Copenhagen, Denmark
John D. Mathews, Menzies School of Health Research, Casuarina NT, Australia
Manfred Neuberger, Department of Preventive Medicine, University of Vienna, Vienna, Austria
Neil Pearce, Department of Medicine, Wellington School of Medicine, Wellington, New Zealand
Rodolfo Saracci, Unit of Environmental Cancer Epidemiology, International Agency for Research on Cancer, Lyon, France.

Date of this Version

1997

Comments

Published in American Journal of Epidemiology, Volume 145, Number 12, June 15, 1997.

Abstract

The authors examined cancer mortality in a historical cohort study of 21,863 male and female workers in 36 cohorts exposed to phenoxy herbicides, chlorophenols, and dioxins in 12 countries. Subjects in this updated and expanded multinational study coordinated by the International Agency for Research on Cancer were followed from 1939 to 1992. Exposure was reconstructed using job records, company exposure questionnaires, and serum and adipose tissue dbxin levels. Among workers exposed to phenoxy herbicides contaminated with 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) or higher chlorinated dioxins, mortality from soft-tissue sarcoma (6 deaths; standardized mortality ratio (SMR) = 2.03, 95% confidence interval (CI) 0.75-4.43) was higher than expected from national mortality rates. Mortality from all malignant neoplasms (710 deaths; SMR = 1.12, 95% CI 1.04-1.21), non- Hodgkin's lymphoma (24 deaths; SMR = 1.39,95% CI 0.89-2.06), and lung cancer (225 deaths; SMR = 1.12,95% CI 0.98-1.28) was slightly elevated. Risks for all neoplasms, for sarcomas, and for lymphomas increased with time since first exposure. In workers exposed to phenoxy herbicides with minimal or no contamination by TCDD and higher chlorinated dioxins, mortality from all neoplasms (398 deaths; SMR = 0.96, 95% CI 0.87-1.06), non- Hodgkin's lymphoma (9 deaths; SMR = 1.00), and lung cancer (148 deaths; SMR = 1.03) was similar to that expected, and mortality from soft-tissue sarcoma was slightly elevated (2 deaths; SMR = 1.35). In a Poisson regression analysis, workers exposed to TCDD or higher chlorinated dioxins had an increased risk for all neoplasms (rate ratio = 1.29,95% CI 0.94-1.76) compared with workers from the same cohort exposed to phenoxy herbicides and chlorophenols but with minimal or no exposure to TCDD and higher chlorinated dioxins. These findings indicate that exposure to herbicides contaminated with TCDD and higher chlorinated dioxins may be associated with a small increase in overall cancer risk and in risk for specific cancers.