The Utility of Proximity-Based Herbicide Exposure Assessment in Epidemiologic Studies of Vietnam Veterans

Committee on Making Best Use of the Agent Orange Exposure Reconstruction Model

Board on Military and Veterans Health

INSTITUTE OF MEDICINE OF THE NATIONAL ACADEMIES

THE NATIONAL ACADEMIES PRESS

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Committee on Making Best Use of the Agent Orange Exposure Reconstruction Model Board on Military and Veterans Health

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THE NATIONAL ACADEMIES PRESS 500 Fifth Street, N.W. Washington, DC 20001 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 respon- sible 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-2136 (Task Order #7) between the National Academy of Sciences and the Department of Veterans Affairs. Any opinions, findings, conclusions, or recommendations expressed in this publica- tion are those of the author(s) and do not necessarily reflect the view of the organi- zations or agencies that provided support for this project. International Standard Book Number-13: 978-0-309-11449-3 International Standard Book Number-10: 0-309-11449-7 Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624-6242 or (202) 334-3313 (in the Washington metropolitan area); Internet, http://www.nap.edu. For more information about the Institute of Medicine, visit the IOM home page at: www.iom.edu. Copyright 2008 by the National Academy of Sciences. All rights reserved. Printed in the United States of America. The serpent has been a symbol of long life, healing, and knowledge among almost all cultures and religions since the beginning of recorded history. The serpent adopted as a logotype by the Institute of Medicine is a relief carving from ancient Greece, now held by the Staatliche Museen in Berlin. Suggested citation: IOM (Institute of Medicine). 2008. The utility of proximity- based herbicide exposure assessment in epidemiologic studies in Vietnam veterans. Washington, DC: The National Academies Press.

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“Knowing is not enough; we must apply. Willing is not enough; we must do.” —Goethe Advising the Nation. Improving Health.

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The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general wel- fare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineer- ing programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is presi- dent of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Insti- tute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sci- ences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and Dr. Charles M. Vest are chair and vice chair, respectively, of the National Research Council. www.national-academies.org

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COMMITTEE ON MAKING BEST USE OF THE AGENT ORANGE EXPOSURE RECONSTRUCTION MODEL DAVID A. SAVITZ (Chair), Charles W. Bluhdorn Professor of Community and Preventive Medicine, Director, Epidemiology, Biostatistics, and Disease Prevention Institute, Mount Sinai School of Medicine MEHRAN ALAEE, Research Scientist, Aquatic Ecosystem Protection Research Division, Environment Canada FRANCESCA DOMINICI, Professor, Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health GURUMURTHY RAMACHANDRAN, Professor, Division of Environmental Health Sciences, University of Minnesota WILLIAM G. SEIBERT, Chief, Archival Operations Branch, Archival Programs Division, National Personnel Records Center, St. Louis, Missouri LESLIE STAYNER, Professor and Director, Division of Epidemiology and Biostatistics, School of Public Health, University of Illinois at Chicago LANCE A. WALLER, Professor, Department of Biostatistics, Rollins School of Public Health, Emory University MARY H. WARD, Investigator, Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Department of Health and Human Services THOMAS F. WEBSTER, Associate Professor, Department of Environmental Health, Boston University School of Public Health SUSAN WOSKIE, Professor, Department of Work Environment, University of Massachusetts Lowell Project Staff LOIS JOELLENBECK, Senior Program Officer JANE S. DURCH, Senior Program Officer JON Q. SANDERS, Program Associate FREDERICK ERDTMANN, Director, Board on Military and Veterans Health PAMELA RAMEY McCRAY, Administrative Assistant ANDREA COHEN, Financial Associate v

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Reviewers T his 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 (NRC’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 for objectivity, evidence, and respon- siveness 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 review of this report: John C. Bailar III, University of Chicago Jan Beyea, Consulting in the Public Interest Norman Breslow, University of Washington S. Katherine Hammond, School of Public Health, University of California, Berkeley Ilene Kesselman, Lockheed Martin Corporation Eric Reiner, Ontario Ministry of the Environment Peggy Reynolds, Northern California Cancer Center John E. Vena, Arnold School of Public Health, University of South Carolina Michael Yost, School of Public Health and Community Medicine, University of Washington vii

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viii REVIEWERS 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 G. Blazer, Duke University Medical Center, and Chris G. Whipple, ENVIRON. Appointed by the NRC and Institute of Medicine, they were 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 authoring committee and the institution.

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Preface C ommittee reports ultimately reflect the collective wisdom of the indi- viduals who served. I believe that our committee provided the full complement of essential technical skills, gave conscientious effort, and ultimately achieved the needed blend of individual voices to respond in consensus to a complex question. Lois Joellenbeck and Jane Durch kept us focused and ensured progress while carefully avoiding influencing the nature of our conclusions, and they deserve much praise for their skillful leadership. Despite more than 30 years of efforts to evaluate whether herbicide spraying affected the health of veterans who served in Vietnam, controversy continues and will likely never be put to rest. With unresolved scientific issues regarding the health effects of the chemicals of concern, most notably the contaminant TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin), and varying judgments regarding the prevalence and levels of exposure experienced by the troops, the Department of Veterans Affairs (VA) has turned to system- atic reviews of the epidemiologic and toxicologic evidence by Institute of Medicine committees as a way to synthesize the evidence and guide deci- sions on compensation. A growing list of conditions has been deemed to be deserving of compensation, with the presumption that those who served in Vietnam were potentially exposed. Controversy is perhaps inevitable given VA’s need to face the challenge of how to balance scientific evidence with the obligation to care for the veterans. Our committee contended with just one specific piece of this very complex array of issues—the best use of a model to characterize exposure to the troops based on their proximity to herbicide spraying in Vietnam. ix

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x PREFACE However, even with a seemingly focused question, it is not possible (or desirable) to ignore the whole array of issues concerning veterans’ health. We faced a number of such issues, including what it would mean if the more refined research using this model provided results that did not sup- port compensation decisions already made, the value of using this model to study veterans’ health in terms of both the scientific contributions to be made and responsiveness to public concerns, and, even more broadly, the potential for improved but still imperfect research to do more good than harm in this charged context. We had the opportunity to hear from those who developed the model and defended its merits and others who were highly critical of the model’s quality and its potential for making contributions to research. We con- sidered the feasibility of implementing the model in light of the available records on troop locations and movement. We considered the potential contributions of this research tool to learning fundamental information about human health effects of exposure to the herbicides and contaminants of concern, especially TCDD. We ultimately came to agree that, despite unavoidable and substantial uncertainty about the herbicide exposure of Vietnam veterans, there is value in direct studies of the health of these veterans largely because it is their health that is the issue at hand. The incremental improvement in classify- ing herbicide exposure during service in Vietnam that the model appears to offer, and the application of that information to studies of veterans’ health, has value because of its potential to enhance our understanding of the health experience of this population. No one on the committee viewed the model and its proximity-based approach to exposure assessment as the silver bullet to resolve all the scientific, compensation, or political controversies surrounding the health of Vietnam veterans. In fact, our greatest concern was the potential for misinterpretation of studies that use this model—that they would be over- interpreted as establishing some “bottom line” finding that would trump the cumulative evidence from studies of herbicides’ health effects in other populations with higher and better measured exposures. If in fact there were a perfect system for measuring herbicide exposure and health out- comes in those who served in Vietnam, it might provide hope for a true bottom line, but even with future refinements, this model does not hold out that promise. Should our recommendations be followed and a series of studies making use of the model emerge, the evidence they generate will be only one contribution among many relevant approaches to addressing the potential link between herbicide exposure and health among veterans. In fact, we recognize that in allocating resources, investing in research using the exposure assessment model to study veterans’ health is but one among an array of strategies for reducing scientific uncertainty about the health

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xi PREFACE effects of herbicides used in Vietnam and may or may not be the most promising. We deliberated carefully and reached a series of conclusions that should help VA decide how to proceed on this issue. With our enumeration of the strengths and limitations of the approach, there is no need to be distracted by those who focus only on its limitations or only on its merits, when both perspectives are valid to varying degrees. If some people advocate for the use of this model as the definitive solution to all the underlying controversy and problems in this field, then the balanced review we provide should counter their arguments. Similarly, the committee’s review also counters those who would dismiss the approach out of hand due to questions regard- ing the model’s assumptions. We have tried to provide comprehensive and objective information about what is ultimately a policy decision: whether to invest the resources to improve, evaluate, and apply the exposure assessment model in health studies. In light of the questions that remain concerning herbicide exposure and health among Vietnam veterans and the array of evidence that has thus far been brought to bear on that issue, we believe that the application of this model and its potential refinements offers a constructive approach to extending knowledge about the effects of herbicides on the health of these veterans and merits the initial steps recommended in our report. David Savitz Chair

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Acknowledgments M any individuals assisted the committee in its work by providing useful data and presenting information at the committee’s public meetings. We thank the following people for participating in the committee’s public meetings: Mark Brown and Han Kang, Department of Veterans Affairs; Jeanne Mager Stellman, SUNY Downstate Medical Center (formerly at Columbia University); Steven Stellman, Columbia University; Richard Boylan, National Archives and Records Administration; David Garabrant, University of Michigan School of Public Health; John Giesy, University of Saskatchewan; Michael Ginevan, M.E. Ginevan and Associates; Donald Hakenson, U.S. Army and Joint Services Records Research Center; Shannon Middleton, American Legion; John Ross, Infoscientific.com, Inc.; Thomas Sinks, Centers for Disease Control and Prevention; Marie Haring Sweeney, National Institute for Occupational Safety and Health; David Tollerud, University of Louisville; Richard Weidman, Vietnam Veterans of America; and Alvin Young, Environmental Science and Pollution Research (editor). The committee also wishes to thank the following individuals who made information available to the committee and study staff: Drue Barrett, Centers for Disease Control and Prevention; Thomas Boivin, Hatfield Con- sultants; Tim Bullman and Yasmin Cypel, Department of Veterans Affairs; Keith Horsley, Australian Institute of Health and Welfare; and Sang-Wook Yi, Kwandong University, South Korea. In addition, Institute of Medicine (IOM) staff members David Butler, Harriet Crawford, William Page, and Mary Paxton met with the committee and aided the study staff in the col- lection and analysis of background material. xiii

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xiv ACKNOWLEDGMENTS The committee offers special thanks to Jeanne Mager Stellman and Steven Stellman, who participated in the committee’s three public meet- ings and responded to several requests for supplemental information. Our project officer from the Department of Veterans Affairs, Mark Brown, pro- vided valuable guidance on the scope of the study as the committee began its work. Also at the Department of Veterans Affairs, Han Kang responded to several requests for additional information. Thanks go as well to other members of the staff of the Institute of Medicine and the National Academies. As a member of the study staff, Jon Sanders ably ensured that logistical and information needs were met. Also supporting the study were Frederick (Rick) Erdtmann, Director, Board on Military and Veterans Health; Andrea Cohen, Financial Associate; Bronwyn Schrecker Jamrok, Manager, IOM Report Review; and Lara Andersen, Senior Editorial Manager. In addition, Robert Pool provided helpful edito- rial services.

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Contents ACRONYMS AND ABBREVIATIONS xvii SUMMARY 1 1 INTRODUCTION AND BACKGROUND 13 Study Charge and Committee Activities, 14 A Brief History, 15 Issues in Assessing Herbicide Exposure in Vietnam for Epidemiologic Studies, 21 The Committee’s Report, 22 References, 22 2 THE HERBICIDE EXPOSURE ASSESSMENT MODEL 25 The Exposure Opportunity Concept, 26 Components of the Herbicide Exposure Assessment Model, 29 Unit Location Information, 32 References, 33 3 ASSESSMENT OF THE MODEL AND ITS CAPACITY TO PRODUCE USEFUL EXPOSURE METRICS 35 An Exposure Assessment Hierarchy for Vietnam Veterans, 36 Infrastructure of the Stellman Team’s Model, 39 Evaluation of the Infrastructure of the Stellman Team’s Model, 43 The Stellman Team’s Exposure Opportunity Metrics, 45 xv

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xvi CONTENTS Evaluation of the Stellman Team’s Exposure Opportunity Metrics, 46 Potential for Corroboration of Exposure Measures, 53 Testing and Refining the Stellman Team’s Model, 57 Conclusions, 59 Research Opportunities, 60 References, 61 4 DATA FOR EPIDEMIOLOGIC STUDIES OF VIETNAM VETERANS 65 Available Troop Location Data, 65 Obtaining Additional Troop Location Data from Military Records, 68 Sources of Health Outcome Information, 76 Conclusions, 80 References, 81 5 RECOMMENDATIONS REGARDING EPIDEMIOLOGIC STUDIES USING THE EXPOSURE ASSESSMENT MODEL 84 Should Studies Be Done Using the Stellman Team’s Model?, 84 Contributions and Pitfalls of Studies Using the Model, 85 General Considerations for Conducting Studies, 91 Types of Studies for Consideration, 97 Potential Study Populations, 99 Ongoing VA Work to Apply the Exposure Assessment Model, 104 Contribution to the Ongoing IOM Reviews of the Association Between Herbicide Exposure and Health Outcomes, 106 Conclusions, 106 Recommendations, 107 References, 108 APPENDIXES A Agendas for Information-Gathering Meetings 113 B Exposure Measures in Studies of U.S. Vietnam Veterans 119 C Biographical Sketches of Committee Members 136

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Acronyms and Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid 2,4,5-T 2,4,5-trichlorophenoxyacetic acid ALS amyotrophic lateral sclerosis ATSDR Agency for Toxic Substances and Disease Registry BIRLS Beneficiary Identification and Record Locator Subsystem CDC Centers for Disease Control and Prevention CMS Centers for Medicare and Medicaid Services CRUR Center for Research of Unit Records CURR Center for Unit Records Research DAAR Daily Air Activities Report DMF Death Master File DoD U.S. Department of Defense EOI exposure opportunity index EPA Environmental Protection Agency ESG U.S. Army and Joint Services Environmental Support Group FOIA Freedom of Information Act xvii

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xviii ACRONYMS AND ABBREVIATIONS g gram GAO Government Accountability Office (previously General Accounting Office) GIS geographic information system HEA-V Herbicide Exposure Assessment–Vietnam IARC International Agency for Research on Cancer IOM Institute of Medicine JSRRC U.S. Army and Joint Services Records Research Center km kilometer MACV U.S. Military Assistance Command, Vietnam MFUA Medical Follow-up Agency NARA National Archives and Records Administration NAS National Academy of Sciences NCHS National Center for Health Statistics NDI National Death Index ng nanogram NHL non-Hodgkin’s lymphoma NLM National Library of Medicine NPRC National Personnel Records Center NRC National Research Council NTIS National Technical Information Service OMPF Official Military Personnel File OPC Outpatient Clinic File PCDD polychlorinated dibenzodioxin PCDF polychlorinated dibenzofuran pg picogram P.L. Public Law ppm parts per million ppt parts per trillion PTF Patient Treatment File PTSD posttraumatic stress disorder ResDAC Research Data Assistance Center

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xix ACRONYMS AND ABBREVIATIONS SNF skilled nursing facility SSA DMF Social Security Administration’s Death Master File TCDD 2,3,7,8-tetrachlorodibenzo-p-dioxin USMC U.S. Marine Corps Universal Transverse Mercator coordinate system UTM VA U.S. Department of Veterans Affairs

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