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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.
Support for this project was provided by the Food and Drug Administration (FDA) prior to the March 2000 decision by the Supreme Court denying FDA comprehensive authority over tobacco products. The views presented in this report are those of the Institute of Medicine Committee to Assess the Science Base for Tobacco Harm Reduction and are not necessarily those of the funding agencies.
Library of Congress Cataloging-in-Publication Data
Clearing the smoke: assessing the science base for tobacco harm reduction/Kathleen Stratton…[et al.], editors.
ISBN 0-309-07282-4 (alk. paper: case)
1. Smoking—Health aspects. 2. Smoking cessation programs. 3. Tobacco habit—Prevention.
[DNLM: 1. Tobacco Smoke Pollution—prevention & control. 2. Biological Markers. 3. Environmental Exposure—adverse effects. 4. Neoplasms—etiology. 5. Nicotine—pharmacology. 6. Smoke—adverse effects. QV 137 C6225 2001] I. Title: Assessing the science base for tobacco harm reduction. II. Stratton, Kathleen R.
RA645.T62 C56 2001
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COMMITTEE TO ASSESS THE SCIENCE BASE FOR TOBACCO HARM REDUCTION
STUART BONDURANT, M.D. (Chair), Professor,
Department of Medicine, University of North Carolina, Chapel Hill
ROBERT WALLACE, M.D., M.Sc. (Vice-Chair), Professor,
Departments of Epidemiology and Internal Medicine, University of Iowa Colleges of Public Health and Medicine
J.RICHARD CROUT, M.D., President,
GARRET FITZGERALD, M.D., Professor and Chair,
Department of Pharmacology, University of Pennsylvania
ADI GAZDAR, M.D., Professor,
Department of Pathology, University of Texas Southwestern Medical Center
GARY GIOVINO, Ph.D., M.S., Senior Research Scientist,
Roswell Park Cancer Institute
DOROTHY HATSUKAMI, Ph.D., Professor,
Department of Psychiatry and Psychology, University of Minnesota
ROGENE F.HENDERSON, Ph.D., Senior Biochemist/Toxicologist,
Lovelace Respiratory Research Institute
PETER REUTER, Ph.D., Professor,
School of Public Affairs and Department of Criminology, University of Maryland
DAVID J.RILEY, M.D., Professor of Medicine,
Division of Pulmonary and Critical Care Medicine, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School
PETER SHIELDS, M.D., Professor and Chief,
Cancer Genetics and Epidemiology Program, Lombardi Cancer Center, Georgetown University Medical Center
JAMES WILLERSON, M.D., Professor and Chair of Internal Medicine,
University of Texas Medical School
Health Promotion and Disease Prevention Board Liaison
KENNETH E.WARNER, Ph.D., Professor,
Department of Health Management and Policy, School of Public Health, University of Michigan
Neuroscience and Behavioral Health Board Liaison
RICHARD J.BONNIE, L.L.B., John S.Battle Professor of Law, Director,
Institute of Law, Psychiatry, and Public Policy, University of Virginia School of Law
NEAL BENOWITZ, M.D., Professor and Chief of the Division of Clinical Pharmacology,
Departments of Medicine, Biopharmaceutical Sciences, and Psychiatry, University of California, San Francisco
CHRISTOPHER LOFFREDO, Ph.D., M.S., Assistant Professor,
Lombardi Cancer Center, Georgetown University Medical Center
KATHLEEN STRATTON, Ph.D., Study Director
PADMA SHETTY, M.D., Program Officer
ANN W.ST. CLAIRE, Senior Project Assistant
ROSE MARIE MARTINEZ, Sc.D., Director,
Board on Health Promotion and Disease Prevention
TERRY PELLMAR, Ph.D., Director,
Board on Neuroscience and Behavioral Health
Tobacco has been used by humans for at least a millennium, and its harmful effects have been suspected for at least 200 years. In the last 50 years, convincing and generally accepted evidence has established the fact that exposure to tobacco products is the major single cause of early human mortality and morbidity in developed nations and in many developing nations as well.
Even nonsmokers suffer morbidity and excess mortality from the toxic effects of inhalation of sidestream smoke. Both smokers and their nonsmoking associates are more likely to be injured in fires and automobile accidents. The personal and social price we pay for establishing and sustaining nicotine addiction through exposure to tobacco smoke is our greatest controllable health cost and one of our greatest social burdens.
It has been scientifically established that reduced exposure to tobacco smoke by lifelong abstinence and avoidance of smoke eliminates the added risk and harm and that cessation, even after many years of smoking, reduces risk and harm both immediately and in the long term for many tobacco-related conditions.
Several smoking cessation programs, some aimed at individuals and some at communities, have been shown to be modestly effective in assisting smokers to quit smoking. These programs have been shown to be more effective with the added use of nicotine replacement by patches for absorption through the skin, by nicotine-containing chewing gum or sprays for absorption through oral or nasal mucous membranes, or by the administration of psychotropic drugs to reduce the desire for nicotine.
However, with the most intensive application of the most effective known programs for prevention and cessation, approximately 10–15% of the adults in the United States are expected to be regular users of tobacco in 2010, and they will continue to suffer the increased incidence of harmful and lethal consequences. Among this group are many who cannot or will not stop using tobacco, and it is to this group that effective programs and products of harm reduction should be directed.
New tobacco products and nicotine replacement products are being marketed frequently and, along with products now on the market, often have associated direct or implied health claims. Some of the new products differ from traditional products in ways that appear minor, whereas others involve substantial changes in types of tobacco, in additives, or in curing, blending, or processing of the tobacco. New products may also change the composition of the aerosol the consumer inhales compared to cigarette smoke by changing the burning temperature of the tobacco by new methods of combustion, by limiting the release of smoke into the atmosphere, by dilution of the smoke with air, and/or by adding unnatural carriers for smoke particles.
Although many components of tobacco are known to be toxic, little is known of the specific dose-response relations of the individual toxins as they occur in cigarette smoke or of the interactions between the constituents of tobacco smoke. There is little direct evidence that removal of specific substances from tobacco smoke or from tobacco actually reduces risk or harm to human health. In considering the health effects of modified tobacco products it is important to remember that the health consequences of the use of any such product are determined not by the toxic agents removed from the product but by the actual exposure to the toxins that remain. Harm reduction is the net difference in harm between the products as actually used.
There is strong evidence that in the range of exposures involved in smoking, there is a quantitative relationship between the magnitude of exposure and the incidence of cancer, coronary vascular disease, pulmonary disease, and several other tobacco-related illnesses. Rarely if ever is there impartial and thorough assessment of the risk associated with new tobacco products relative to the risk of abstinence or the risk of other tobacco products prior to marketing. Unlike new tobacco products, nicotine replacement products are subject to full disclosure of content, rigorous testing, and the regulation of marketing claims by the of the Food and Drug Administration.
In addition to cigarette smoke, other forms of tobacco such as cigars, chewing tobacco, and snuff are also vectors of nicotine addiction and often have their own sets of serious toxic consequences.
The latent period between beginning exposure to tobacco and the development of most of the major adverse consequences is so long that empirical, direct evidence (assessment of immediate and long-term toxicity of individual tobacco products in humans) that one tobacco product is less harmful than another will rarely be available in time to be a basis for informing users. In the absence of direct evidence, conflicting claims of the degree of harm reduction are likely and informed usage decisions by smokers and nonsmokers will be difficult.
No one knows the dose-response relations, the specific toxins, the pathogenic mechanisms, or the interrelationship between the many components of tobacco smoke with enough precision to make scientifically reliable quantitative judgments about the risk or actual harm reduction associated with use of any tobacco product. Since we do not know which of many toxins may be the cause of specific harmful effects, we can only infer but we cannot know the health effects of the elimination of any one or several tobacco components. Further, we are just beginning to identify and understand the genetic basis and other causes of the differences in susceptibility to toxic effects among groups or individuals that largely determine the response of an individual to a toxin.
Nonetheless, it is reasonable to expect that some of the new products will reduce exposure to tobacco toxins and possibly reduce harm to some users and to others who are exposed to them. It is, therefore, urgent and important that the assessment of exposure to tobacco toxins resulting from the use of modified tobacco products or drugs be based on the best available evidence, made by the most qualified judges, and communicated to policy makers and the public completely and honestly.
There is little direct evidence available to serve as a basis for judgment as to the potential for harm reduction of specific new tobacco and pharmaceutical products. Therefore, any conclusions as to the relative harm of these products must necessarily be inferred from a base of indirect knowledge. The continuing introduction of new tobacco products with implicit or explicit claims of risk or harm reduction makes it important and urgent that the capacity for the best possible scientific assessment of these claims be put in place.
Since even the availability of harm reduction products may deter some from following the healthier course of abstinence or cessation, assessment of health claims should be based on an estimate of the effect of the product on the prevalence of smoking in the population, as well as the effect on the health risk to the individual smoker.
The most reliable scientific interpretation of necessarily incomplete indirect evidence comes when individuals who are experts in the related fields are not biased and are free of conflict of interest form a consensual
judgment. Such a judgment based on evidence of high quality should be a requirement for a conclusion that the use of a product is in fact associated with decreased exposure to toxins and that the decreased exposure is likely to be associated with less harmful outcomes.
Further, since these judgments of risk will necessarily be inferential because they are based on indirect and inconclusive evidence, some form of postmarketing surveillance of each product is important.
The charge to the committee is to address the science base for harm reduction from tobacco. The committee concluded early in its deliberations that the science base for harm reduction will evolve over time. There will inevitably be important interactions between the types of products that are developed and the science base. There will also be interactions between any regulatory process and the science base (the science base will influence regulation, and regulation will focus pertinent science) and, obviously, between regulations and products. For these reasons, the committee realized that the science base for harm reduction can be usefully considered only in the context of some sense of the types of specific products and of the consequences of regulation. Accordingly, portions of this report address both general categories of potential harm reduction products and regulatory considerations.
It is the strong sense of the committee that claims of less harm or risk associated with the use of tobacco products or drugs should be available—but only if four conditions are met: (1) There should be strong and widely available programs designed to avoid initiation and to achieve abstinence; (2) There should be premarketing evidence satisfactory to a group of disinterested experts that—as the product will actually be used by consumers—there is less exposure to toxic agents without coincidental increase in harm to the individual from other smoke components or to the population from encouraging initiation or continuation of smoking, the burden of proof of assertions of harm reduction should rest entirely with those making the assertion; (3) The public should be fully informed of the strength of the claims as assessed by an independent panel of experts; and (4) There should be an effective surveillance system in place to determine short-term behavioral and the long-term health consequences of the use of the new products.
The committee wishes to express its great appreciation to the many individuals, listed in Appendix B, who contributed generously and substantially to its deliberations. Representatives of many health agencies as well as tobacco interests responded thoughtfully and extensively to the committee’s questions.
Dr. Kathleen Stratton contributed perspective, insight, meticulous attention to detail, and essential oversight to the work and report. This
report would not be possible without her substantial and important contributions.
Dr. Padma Shetty assumed responsibility for blocks of the report, and both the full report and many specific parts are testimony to her analytic, organizational, and expressive proficiency. Ann St. Claire organized the arrangements for the work of the committee with great finesse and also made useful contributions to the analytical work of the committee. Every member of the committee is deeply appreciative of the work of Dr. Stratton, Dr. Shetty, and Ms. St. Claire.
The report was reviewed 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 to assist the authors and the Institute of Medicine 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 content of the review comments and the draft manuscript remain confidential to protect the integrity of the deliberative process. The committee wishes to thank the following individuals for their participation in the report review process:
Daniel Azarnoff, D.L.Azarnoff Associates
Alfred Fishman, University of Pennsylvania
Margaret Gilhooley, Seton Hall University
Jack Henningfield, Pinney Associates
Peter Barton Hutt, Covington and Burling
Roger McClellan, Chemical Industry Institute of Toxicology, President Emeritus
Patricia Dolan Mullen, University of Texas
Peter Nowell, University of Pennsylvania
William Parmley, University of California, San Francisco
Thomas Pearson, University of Rochester
Frederica Perera, Columbia University
John Pierce, University of California, San Diego
Stephen Rennard, University of Nebraska
Joseph Rodricks, The Life Sciences Consultancy
Jonathan Samet, Johns Hopkins University
Thomas Schelling, University of Maryland
John Slade, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School
Judith Wilkenfeld, Campaign for Tobacco Free Kids
Gerald Wogan, Massachusetts Institute of Technology
Raymond Woosley, Georgetown University
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 David Challoner, (review monitor) University of Florida and Hugh Tilson, (review coordinator) University of North Carolina. Appointed by the
National Research Council 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.