NATIONAL ACADEMY 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.
The Institute of Medicine was chartered in 1970 by the National Academy of Sciences to enlist distinguished members of the appropriate professions in the examination of policy matters pertaining to the health of the public. In this, the Institute acts under the Academy’s 1863 congressional charter responsibility to be an adviser to the federal government and its own initiative in identifying issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine.
Support for this study was provided by the Department of Veterans Affairs (contract no. V101(93)P-1331).
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COMMITTEE TO REVIEW THE HEALTH EFFECTS IN VIETNAM VETERANS OF EXPOSURE TO HERBICIDES (SECOND BIENNIAL UPDATE)
Michael Aminoff, MD,2 Professor,
Department of Neurology, University of California at San Francisco School of Medicine
Steven Goodman, MD, MHS, PhD, Associate Professor,
Department of Oncology, Division of Biostatistics, Johns Hopkins University School of Medicine
Robert Herrick, PhD, CIH, Lecturer on Industrial Hygiene,
Department of Environmental Health, Harvard School of Public Health
Irva Hertz-Picciotto, PhD, Associate Professor,
Department of Epidemiology, University of North Carolina, Chapel Hill
David Hoel, PhD, Distinguished University Professor,
Medical University of South Carolina
Department of Epidemiology, University of North Carolina, Chapel Hill
Trevor Orchard, MBBCh, MMSc, Professor,
University of Pittsburgh, Rangos Research Center
Howard Ozer, MD, PhD, Professor,
Department of Medicine, MCP Hahnemann University
Kenneth Ramos, PhD,2 Professor,
Department of Physiology and Pharmacology, Texas A&M University College of Veterinary Medicine
Noel Rose, MD, PhD,2 Professor,
Department of Molecular Microbiology and Immunology, Johns Hopkins University School of Hygiene and Public Health
DAVID A. BUTLER, Study Director
SANJAY S. BALIGA, Research Associate
JAMES A. BOWERS, Research/Project Assistant
KATHLEEN R. STRATTON, Director,
Division of Health Promotion and Disease Prevention
DONNA D. DUNCAN, Division Assistant
SHARON GALLOWAY, Financial Associate
JANE DURCH, Senior Program Officer,
Institute of Medicine
CAROL MACZKA, Director of Toxicology and Risk Assessment,
National Research Council
FLORENCE POILLON, Contract Editor
In response to the concerns voiced by Vietnam veterans and their families, Congress called upon the National Academy of Sciences (NAS) to review the scientific evidence on the possible health effects of exposure to Agent Orange and other herbicides (Public Law 102-4, enacted on February 6, 1991). The creation of the first NAS Institute of Medicine (IOM) committee, in 1992, underscored the critical importance of approaching these questions from a non-partisan scientific standpoint. The original Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides realized from the beginning that it could not conduct a credible scientific review without a full understanding of the experiences and perspectives of veterans. Thus, to supplement its standard scientific process, the committee opened several of its meetings to the public in order to allow veterans and other interested individuals to voice their concerns and opinions, to provide personal information about individual exposure to herbicides and associated health effects, and to educate committee members on recent research results and studies still under way. This information provided a meaningful backdrop for the numerous scientific articles that the committee considered.
Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam (abbreviated as VAO in this report) reviewed and evaluated the available scientific evidence regarding the association between exposure to dioxin or other chemical compounds contained in herbicides used in Vietnam and a wide range of health effects. The report provided information for the Secretary of Veterans Affairs to consider as the Department of Veterans Affairs carried out its responsibilities to Vietnam veterans. It also described areas in which the available scientific data were insufficient to determine whether an association exists and provided the committee's recommendations for future research.
Public Law 102-4 also tasked the NAS to conduct biennial updates that would review newly published scientific literature regarding statistical associations between health outcomes and exposure to dioxin and other chemical compounds in these herbicides. The first of these, Veterans and Agent Orange: Update 1996 (Update 1996) was published in March of that year. The focus of this second updated review is on scientific studies published since the release of Update 1996. To conduct the review, the IOM established a committee of 12 members representing a wide range of expertise to take a fresh look at the studies reviewed in VAO and Update 1996 along with the newest scientific evidence. In order to provide a link to the experience and expertise developed by the previous committees, five of the members of the committee responsible for this report were recruited from the committee responsible for Update 1996; two of these individuals also served on the VAO committee. 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 dioxin exposure. Biographical sketches of committee members and staff appear in Appendix C.
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 procedures of the NAS, the committee met in a series of closed sessions and working group meetings in which members could freely examine, characterize, and weigh the strengths and limitations of the evidence. It also convened two open meetings to provide the opportunity for veterans and veterans service organizations, researchers, policymakers, and other interested parties to present their concerns, review their research, and exchange information directly with committee members. The first of these was held in conjunction with the committee's second meeting in June 1997 in Washington, D.C.; the second in Irvine, California, in October, 1997. To solicit broad participation, the committee sent announcements to individuals, organizations, and listserves known to have an interest in this issue. The oral presentations and written statements submitted to the committee are described in detail in Appendix A. In order to address one area of interest identified by the Department of Veterans Affairs, the committee convened a workshop on the combination and reanalysis of existing data on the health effects of herbicide and dioxin exposure. The workshop, which took place in August 1997, brought together experts in these methodologies with researchers who have developed and analyzed datasets evaluating the health of Vietnam veterans and individuals exposed to herbicides or dioxin. The results of this effort will be addressed in a separate report.
In addition to its formal meetings, the committee actively and continuously sought information from, and explained its mission to, a broad array of individuals and organizations with interest or expertise in assessing the effects of expo-
sure to herbicides. The committee also heard from the public through telephone calls, letters, and emails.
This report has been reviewed in draft form by individuals 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 the published report as sound as possible and to ensure that the report meets institutional standards for 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 individuals for their participation in the review of this report: Patricia Buffler, University of California, Berkeley; Graham Colditz, Harvard University; John Doull, University of Kansas; Kristine Gebbie, Columbia University; David Kriebel, University of Massachusetts, Lowell; Gilbert Omenn, University of Michigan; Jonathan Samet, Johns Hopkins University; David Strogatz, University of Albany, SUNY. While the individuals listed above have provided constructive comments and suggestions, it must be emphasized that responsibility for the final content of this report rests entirely with the authoring committee and the institution.
David A. Butler served as the study director for this project and deserves credit for drafting sections of the report. The committee would also like to acknowledge the excellent work of IOM staff members Sanjay Baliga and James Bowers. Carol Maczka of the Academy's National Research Council provided invaluable help on the toxicology chapter of the report. Thanks are also extended to Sharon Galloway, who handled the finances for the project; Florence Poillon and Jane Durch, who provided excellent editorial skills; Susan Fourt, who conducted database searches; Michael Edington, who supervised the report through the editorial and publication phases; and Donna Thompson, who provided administrative support to the project. The knowledge and experience of Michael Stoto and Catharyn Liverman, who served as staff members on the original committee, were helpful in this effort.
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 Drs. Bruce Armstrong (New South Wales Cancer Council, Australia), Michael DeVito (U.S. EPA), Keith Horsley (Commonwealth Department of Veterans' Affairs, Australia), Han Kang (U.S. Department of Veterans Affairs), Stephen Katz (National Institutes of Health, DHHS), Edward McCarthy (Johns Hopkins University), Joel Michalek (Armstrong Laboratory, USAF), and Jerry Rice (International Agency for Research on Cancer).