Veterans and Agent Orange
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THE NATIONAL ACADEMIES PRESS
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NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
This study was supported by Contract No. V101(93)P-1637, TO#30 between the National Academy of Sciences and the US Department of Government Affairs. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for this project.
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COMMITTEE TO REVIEW THE HEALTH EFFECTS IN VIETNAM VETERANS OF EXPOSURE TO HERBICIDES (FIFTH BIENNIAL UPDATE)
JOHN J. STEGEMAN, (Chair), Senior Scientist,
Woods Hole Oceanographic Institution, Department of Biology, Woods Hole, Massachusetts
KIROS T. BERHANE, Associate Professor,
Department of Preventive Medicine, University of Southern California, Los Angeles, California
PAUL F. ENGSTROM, Senior Vice President and Medical Director,
Fox Chase Network, Philadelphia, Pennsylvania
RICHARD A. FENSKE, Professor of Environmental and Occupational Health Sciences and Director of the Pacific Northwest Agricultural Safety and Health Center,
University of Washington, Seattle, Washington
JORDAN FIRESTONE, Assistant Professor of Neurology, Clinic Director of Occupational and Environmental Medicine,
University of Washington, Seattle, Washington
THOMAS A. GASIEWICZ, Professor and Chair of Environmental Medicine and Director of the Environmental Health Sciences Center,
University of Rochester, Rochester, New York
CLAUDIA HOPENHAYN, Assistant Professor, College of Public
Health, University of Kentucky, Lexington, Kentucky
LOREN D. KOLLER, Consultant,
Environmental Health and Toxicology, Corvallis, Oregon
NANCY I. KERKVLIET, Professor,
Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, Oregon
JOEL MCCULLOUGH, Medical Director of Environmental Health,
Chicago Department of Health, Chicago, Illinois
DAVID S. STROGATZ, Associate Professor and Chair of Epidemiology,
School of Public Health, State University of New York at Albany, New York
Michelle C. Catlin, Study Director (through October 2004)
Mary Burr Paxton, Study Director (as of November 2004)
Jennifer A. Cohen, Senior Program Associate
Rose Marie Martinez, Director,
Board on Health Promotion and Disease Prevention
David Butler, Senior Program Officer
Sonia J. Cheruvillil, Senior Program Assistant (as of October 2004)
Joseph A. Esparza, Senior Program Assistant (through May 2004)
Peter James, Senior Program Assistant
Kate Kelly, Senior Editor
This report has been reviewed in draft form by persons chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council’s Report Review Committee. The purpose of this independent review is to provide candid and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards of objectivity, evidence, and responsiveness to the study charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following for their review of this report:
Hans Berkel, President and CEO, Cancer Prevention Institute, Dayton, Ohio
Linda S. Birnbaum, Director, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina
Margit L. Bleecker, Director, Center for Occupational and Environmental Neurology, Baltimore, Maryland
Norman Breslow, Professor, Department of Biostatistics, University of Washington, Seattle, Washington
Mark R. Cullen, Professor, Occupational and Environmental Medicine Program, Yale University School of Medicine, New Haven, Connecticut
Chris Gennings, Professor, Department of Biostatistics, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia
Russ B. Hauser, Associate Professor, Occupational Health Program, Harvard School of Public Health, Boston, Massachusetts
Robert F. Herrick, Senior Lecturer on Industrial Hygiene, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts
Howard M. Kipen, Director, Occupational Health Division, Environmental and Occupational Health Sciences Institute, Rutgers University, Piscataway, New Jersey
Stephen H. Safe, Professor, Texas A&M Institute for Biosciences and Technology, College Station, Texas
Herbert H. Schaumburg, Professor, Albert Einstein College of Medicine, Yeshiva University, Bronx, New York
Bailus Walker, Jr., Professor, Howard University Cancer Center, Washington DC
Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the conclusions or recommendations, nor did they see the final draft of the report before its release. The review of this report was overseen by Dan Blazer, Duke University Medical Center, Durham, North Carolina. Appointed by the Institute of Medicine, he was responsible for making certain that an independent examination of this report was carried out in accordance with institutional procedures and that all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the author committee and the institution.
In 1991, because of continuing uncertainty about the long-term health effects on Vietnam veterans who where exposed to herbicides during their service in Vietnam (mixtures of 2,4-dichlorophenoxyacetic acid [2,4-D], 2,4,5-trichlorophenoxyacetic acid [2,4,5-T], and its contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD], picloram, and cacodylic acid), Congress passed Public Law 102-4, the Agent Orange Act of 1991. That legislation directed the Secretary of Veterans Affairs to ask the National Academy of Sciences (NAS) to perform a comprehensive evaluation of scientific and medical information regarding the health effects of exposure to Agent Orange, other herbicides used in Vietnam, and the various chemical components of those herbicides, including TCDD. The resulting report, Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam (VAO) was published by the NAS Institute of Medicine (IOM) in 1994. The Secretary also asked that NAS conduct updates at least every 2 years for 10 years from the date of the first report to review newly available literature and draw conclusions from the overall evidence. PL 107-103, The Veterans Education and Benefits Expansion Act of 2001, extended the updates until 2014.
The first report in the resulting series was Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam (abbreviated as VAO in this report). It evaluated and integrated the scientific evidence regarding statistical associations between health outcomes and exposure to TCDD or other compounds in these herbicides that had accumulated prior to 1994. Public Law 102-4 also required the NAS to conduct biennial updates that would review newly published scientific literature regarding such associations. The first of these, Veterans and Agent Orange: Update 1996 (Update 1996) was published in March of that year. The second, Veterans and Agent Orange: Update 1998 (Update 1998) was pub-
lished in 1999. The third, Veterans and Agent Orange: Update 2000 (Update 2000) was published in 2001. The fourth, Veterans and Agent Orange: Update 2002 (Update 2002) was published in 2003.
The focus of this fifth updated review is on scientific studies published since the release of Update 2002. To conduct the review, the IOM established a committee of 11 members representing a wide range of expertise to take a fresh look at the studies reviewed in VAO, Update 1996, Update 1998, Update 2000, and Update 2002, along with the newest scientific evidence. To provide a link to the experience and expertise developed by the previous committees, seven of the members of the committee responsible for this report were recruited from the committee responsible for Update 2002. All committee members were selected because they are leading experts in their fields, have no conflicts of interest with regard to the matter under study, and have taken no public positions concerning the potential health effects of herbicides in Vietnam veterans or related aspects of herbicide or TCDD exposure. Biographical sketches of committee members and staff appear in Appendix D.
The committee worked on several fronts in conducting this updated review, always with the goal of seeking the most accurate information and advice from the widest possible range of knowledgeable sources. Consistent with NAS procedures, the committee met in a series of closed sessions in which members could freely examine, characterize, and weigh the strengths and limitations of the evidence. It also convened open meetings in May and July 2004 to provide the opportunity for veterans and veterans’ service organizations, researchers, policy-makers, and other interested parties to present their concerns, review their research, and exchange information directly with committee members. The oral presentations and written statements submitted to the committee are listed in Appendix B. The committee thanks the individuals who provided valuable insights into the health problems experienced by Vietnam veterans.
The committee is grateful to Michelle Catlin and Mary Paxton, who skillfully served as study directors for this project. The committee would also like to acknowledge the excellent work of IOM staff members Jennifer Cohen, Joe Esparza, Peter James, Sonia Cheruvillil, and David Butler. Thanks are also extended to Jim Banihashemi and Christie Bell, who handled the finances for the project; Kate Kelly, who provided editorial skills; and William McLeod, who conducted database searches.
The committee also benefited from the assistance of several scientists and researchers who generously lent their time and expertise to help give committee members insight on particular issues, provide copies of newly released research, or answer queries concerning their work. Special thanks are extended to Dr. Joel Michalek (Air Force Research Laboratory, Brooks Air Force Base, Texas) for presenting his most recent data at a public session.
John Stegeman, Chair