Section I
Introduction, Background, and Conclusions



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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction Section I Introduction, Background, and Conclusions

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction This page in the original is blank.

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction 1 Introduction “…tobacco use, particularly among children and adolescents, poses perhaps the single most significant threat to health in the United States.” Justice Sandra Day O’Connor, FDA v. Brown & Williamson Tobacco Corp. et al. 2000. “…as a practical matter, it is important to appreciate that a virtually harmless cigarette smoked by only 1% of the population will have a lesser impact on the reduction of tobacco-related diseases than a somewhat more harmful cigarette smoked by 80% of the total smoking population. Research on the less harmful cigarette should therefore be directed toward developing a cigarette containing the lowest possible amount of harmful elements for all tobacco-related diseases, but one that has sufficient acceptability for the largest segment of smokers.” Ernst Wynder, Banbury Conference of Safer Cigarettes, 1979. “…the use of tobacco, especially cigarette smoking, has been causally linked to several diseases. Such use has been associated with increased deaths from lung cancer and other disease, notably coronary artery disease, chronic bronchitis, and emphysema. These widely reported findings, which have been the cause of much public concern over the past decade have been accepted in many countries by official health agencies, medical associations, and voluntary health organizations.” Smoking and Health, Report of the Advisory Committee to the Surgeon General of the Public Health Service, 1964.

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction Knowledge of the devastating consequences of tobacco use to human health has burgeoned in the 37 years since release of the first U.S. Surgeon General’s report on smoking and health (U.S. Public Health Service, 1964). As scientific evidence has steadily accumulated, policy actions and the political will to reduce this toll have waxed and waned. Tobacco-caused death, illness, personal suffering, and costs are a major scourge of our time. If the toll due to tobacco were instead due to an infectious agent for example, most societies would move vigorously to stem the losses with every resource. Public health, medical, and tobacco control professionals, however, continue their campaign against a major threat to the public health. Numerous products that make implied or explicit claims to reduce the burden of smoking while allowing continued nicotine consumption or smoking are now entering the market. This report is concerned with the evaluation of these products. Nearly one-quarter of adult Americans—an estimated 47 million people—smoke cigarettes (CDC, 2000a). Although this is far lower than the 42% recorded in 1965, the decline in the rates of smoking among adults appears to have leveled off during much of the 1990s (PHS, 2000). A slightly higher percentage of American men (26%) than women (22%) currently smokes (CDC, 2000a). Smoking rates vary greatly among racial and ethnic groups within the United States (CDC, 2000b). American Indians or Alaskan Natives have much higher smoking rates than the national average, and Asians or Pacific Islanders have much lower rates (CDC, 2000a). The prevalence of adolescents in the United States who report current smoking is high. In a recent survey, 12.8% of middle school children and 34.8% of high school students reported some form of tobacco use during the month prior to their being interviewed (CDC, 2000c). The vast majority of smokers begin tobacco use during adolescence (IOM, 1994). The important role of adolescent smoking in lifetime addiction and smoking-caused disease is an important justification for many tobacco control policies in the United States. These high rates of tobacco use continue despite statistics showing that 70% of smokers say they want to quit (CDC, 1994) and 34% of smokers make an attempt to quit each year. However, 2.5% of smokers (or less than 10% of those who try) quit smoking (CDC, 1993b). Approximately half of high school seniors who smoked reported that they expect not to be smoking five years from the time of the survey (1976–1984), but 80% of those who smoked more than a half-pack per day were still smoking at follow-up (CDC, 1994). A recent study of high school students reported that almost three-fourths of those who currently smoked had tried to quit (CDC, 1998).

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction The reasons for great national concern over tobacco use are well known. The harm to human health from tobacco use is well documented and has been for decades. Large-scale epidemiological studies conducted in the 1950s supported the causal relationship between cigarette smoking and lung cancer and other diseases. These studies detailed the dose-response relationship between number of cigarettes smoked and individual risk for lung cancer. The 1964 Surgeon General’s report stated that cigarette smoking was causally associated with lung cancer in men. The evidence for a causal relation in women was suggestive in 1964 but not considered established until 1971. It is now known that smoking also causes cancers of the oral cavity, esophagus, and larynx and is a contributing cause of cancers of the pancreas, bladder, kidney, and cervix. Smokers are at increased risk of lung cancer (a sixteenfold increase), chronic obstructive pulmonary disease (COPD; twelvefold), and a myocardial infarction (twofold) (Fielding et al. 1998). Pregnant women who smoke have twice the risk of nonsmokers of delivering low-birth weight infants. The Surgeon General of the United States has continued to publish reports on smoking and health. Some of the most significant publications are listed in Box 1–1. Cigarette smoking is often called the single leading preventable cause of death in the United States (U.S. DHHS, 2000). Smoking results in more deaths each year in the United States than AIDS, alcohol, cocaine, heroin, homicide, suicide, motor vehicle crashes, and fires combined. Primary causes of death from tobacco are cardiovascular disease (approximately 906,600 deaths between 1990–1994), cancer (approximately 778,700 deaths between 1990–1994), and respiratory disease (approximately 454,800 deaths between 1990–1994) (CDC, 1993a). For 1990, smoking was estimated to be the cause of 20% of deaths from ischemic heart disease, 29% of all cancer deaths, 83% of lung cancer deaths, and 79% of COPD deaths. The average reduction in life expectancy for smokers is 6.6 years (Lew and Garfinkel, 1987). Detailed descriptions of the epidemiology of tobacco health effects can be found in Chapters 12–16 of this report. The prevalence of tobacco use varies greatly outside the United States. A recent study from the World Bank reports that 59% of males in the regions of East Asia, the Pacific, Eastern Europe, and Central Asia smoke (World Bank, 1999). The prevalence of female smoking in these regions ranges from 4 to 26%. Worldwide, tobacco use is the sixth leading cause of lost disability-adjusted life-years, a measurement that combines the effects of morbidity and mortality for comparative purposes between and across health outcomes (Murray and Lopez, 1997). The World Health Organization (WHO) estimates that by 2030, tobacco will kill 10 million people per year worldwide (WHO, 1999), making it the leading cause of

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction BOX 1–1 Select Surgeon General’s Reports Regarding Tobacco 1964 Report concluded that smoking causes cancer and other serious diseases. 1967 Report concluded that “cigarette smoking is the most important of the causes of chronic non-neoplastic bronchiopulmonary diseases in the United States.” The report also identified measures of morbidity associated with smoking. 1969 Report made solid conclusions regarding the relationship between maternal smoking and low infant birthweight. It also identified evidence of increased incidence of prematurity, spontaneous abortion, stillbirth, and neonatal death. 1972 Report associated smoking with cancers of the oral cavity and esophagus. 1973 Report studied immunological effects of tobacco and tobacco smoke, and identified carbon monoxide, nicotine, and tar as the smoke constituents most likely to produce health hazards from smoking. 1977-1978 Report focused on health effects of smoking on women, noting in particular the effects of oral contraceptives and smoking on the cardiovascular system. 1980 Report addressed women and smoking projecting that lung cancer in women will surpass breast cancer as the leading cause of cancer mortality. 1981 Report examined the health consequences of lower-tar and nicotine cigarettes. 1983 Report evaluated health consequences of smoking for cardiovascular disease, declaring cigarette smoking one of the three primary causes of coronary heart disease. 1984 Report examined the health effects of smoking on chronic obstructive lung disease (COLD). Smoking accounted for 80–90% of COLD deaths in the United States. 1986 Report concluded that involuntary smoking is a cause of disease in healthy nonsmokers. 1988 Report stated that nicotine is addicting. 1989 Report reported that cigarette smoking is a major cause of cerebrovascular diseases (stroke). The report addressed the future of nicotine addiction in light of new nicotine delivery systems test marketed in 1988 and associated smoking with cancer of the uterine cervix. 1990 Report presented data on the benefits of smoking cessation for most smoking-attributable diseases. Also, presented association of smoking with bladder and cervical cancers. 1994 Report looked at preventing tobacco use among young people including initiation, cessation, advertising influences, and school-based programing. 1998 Report examined tobacco use among U.S. racial and ethnic minority groups showing that patterns of use vary among these groups. 2000 Report analyzes approaches to reducing tobacco use and the future of tobacco control.

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction avoidable premature death in the developing world, as it is in developed countries today. In recognition of the difficulties of cessation, the WHO Framework Convention on Tobacco Control has been reviewing scientific information on harm reduction as part of its overall strategies. However, despite the morbidity and mortality caused by tobacco and widespread knowledge by adults and adolescents of its adverse health effects, tobacco use continues. The biologically active component in tobacco that is primarily responsible for this is nicotine. Nicotine acts on several organs, including the brain. Nicotine is pleasurable to the user, and it is addictive. Thus, many but not all tobacco users find it very difficult to break their addiction and reduce the risk to their health. The continuing toll of tobacco use has prompted the public health community to consider anew harm reduction approaches for tobacco. Tobacco harm reduction refers simply to the goal of reducing harm to health from tobacco use, including environmental tobacco smoke (ETS). Harm avoidance is achieved by never using tobacco products or having contact with ETS. Harm is minimized by quitting tobacco use and reducing exposure to ETS. For the purposes of this report—and as the term is commonly used in other disciplines—harm reduction refers to minimizing harms and decreasing total morbidity and mortality, without completely eliminating tobacco and nicotine use. This definition acknowledges that a significant proportion of individuals will continue to use tobacco for the foreseeable future. Harm reduction can be accomplished by decreasing the risk of an act (e.g., tobacco use), by decreasing the intensity per user, or by decreasing the prevalence. Chapter 2 includes a detailed discussion of harm reduction in other areas of public health concern and sets forth some general principles relevant to tobacco. A multitude of policy strategies, such as increased taxes, contribute to the goal of harm reduction. However, this report focuses on substituting conventional tobacco use with either newly developed so called less harmful tobacco products or with pharmaceutical preparations used alone or concomitantly with decreased use of conventional tobacco products. The committee uses the terms harm-reducing or risk-reducing. The term “safer cigarette” has often been used historically and colloquially. The committee avoids the term “safer” in particular in order to avoid any impression that such products are safe. They are not. The U.S. cigarette manufacturers have recently publicly echoed the public health community’s assertion that that there is no safe cigarette (Philip Morris USA, 2000; R.J. Reynolds Tobacco Company, 2000). Despite any promised harm reduction, the use of tobacco harm reduction products poses greater risks than no tobacco exposure.

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction HISTORY OF HARM REDUCTION Attempts to reduce the known or suspected risks to health from tobacco use by modifying tobacco or cigarettes predate the first U.S. Surgeon General’s report on smoking and health. One of the first product innovations introduced with the potential and promise of harm reduction was filters. Filters reduce the amount of toxicants that go into the smoke inhaled by a smoker. The sale of filter cigarettes went from 1% of the market in 1952 to more than half of the market by 1960 (U.S. DHHS, 1989). In 1998, 98% of cigarettes sold in the United States contained filters (FTC, 2000). The next major product modification with safety implications was the introduction of “low-yield” cigarettes. These products emit lower tar, carbon monoxide (CO), and nicotine than other products as measured by the Federal Trade Commission (FTC) assay (the “smoking machine”). This is achieved through blending different types of tobacco, ventilation, addition of accelerants, and filtration, as discussed in Chapter 4. The utility, purpose, and inferences made of the FTC assay yields are discussed in Chapters 4 and 11. Consumers believed, and still do, that these products pose less risk to health than other cigarettes. Typical advertising campaigns for low-yield products stressed the softer side of smoking: “For smokers who prefer the lighter taste of a low-tar cigarette” (Kluger, 1997). An advertisement in the mid-1970s for a low-yield product, True, stated, “Considering all I’d heard, I decided to either quit or smoke True. I smoke True” (Pollay and Dewhirst, 2000). The market share of products yielding 15 mg of tar or less (as measured by the FTC assay) increased from 4% in 1970 to more than 50% in 1981. These products commanded approximately 80% of the U.S. cigarette market in 1998 (FTC, 2000). Data on the health impact of low-yield products are conflicting, in part due to a lack of systematic and comprehensive study early in the introduction of these products. Most current assessments of the epidemiological and toxicological data suggest, however, that low-yield products are associated with far less health benefit than predicted based on FTC assay-generated tar, CO, and nicotine levels. The sales-weighted average of tar and nicotine yields of cigarettes in the United States has decreased by approximately half since the 1950s (Health Canada, 1998), without a significant or proportional change in the harm or prevalence of specific smoking-related diseases. Some of this is explained by changes in smoking behavior, known as compensatory smoking. In an effort to maintain adequate exposure to nicotine, smokers who use low-yield products smoke differently (e.g, inhale more deeply) than those who smoke higher-yield products. Thus, exposure to tobacco toxicants from low-yield products is

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction greater by an unknown amount than predicted by FTC assay values. In addition to the disappointing impact of low-yield products on an individual smoker’s health, of concern is the health burden of smokers who might have quit smoking altogether had they not had the opportunity to switch to a product they assumed was less harmful. DEFINITIONS Definitions of tobacco products are important for legal and regulatory purposes. Definitions are important also as the reader considers the harm reduction strategies discussed in this report. The Food and Drug Administration (FDA), as part of its rule-making process in 1995–1996, defined a cigarette as “any product which contains nicotine, is intended to be burned under ordinary conditions of use, and consists of any roll of tobacco wrapped in paper or in any substance not containing tobacco; or any roll of tobacco wrapped in any substance containing tobacco which, because of its appearance, the type of tobacco used in the filler, or its packaging and labeling, is likely to be offered to, or purchased by, consumers as a cigarette” (21 CFR 897.3). The Bureau of Alcohol, Tobacco and Firearms uses a very similar definition of a cigarette for purposes of taxation (27 CFR 290). Some potential harm reduction strategies involve specific modifications of conventional cigarettes, as defined above. The committee struggled with terms for other products, which currently exist or could be developed, that are similar to, but not exactly, what is commonly recognized as a cigarette. When strict adherence to the FDA definition of a cigarette (which seems to require the presence of both nicotine and tobacco and to be dependent on high-temperature burning) is not intended, the committee uses the term “cigarette-like.” These products are basically paper-covered cylinders of approximately 90 mm length that, when lit, heated or burned (usually controlled in a very rigorous manner and at lower temperatures than conventional cigarettes), and puffed, allow smoke or vapors with what is recognized as the flavor of tobacco or cigarettes to be inhaled, leading to the absorption of nicotine into the body. When referring both to modifications of conventional cigarettes and to cigarette-like products, the committee uses “tobacco-related.” When referring specifically to pharmaceutical preparations, it will be noted. There is no evidence currently that use of any product, other than those that lead to cessation, can achieve harm reduction from tobacco. Many tobacco and cigarette-like products have been introduced in the distant and recent past that do, under measurement systems such as the smoking machine, result in decreased emission of some toxicants compared to conventional tobacco products. These products could, therefore,

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction potentially result in reduced exposure to toxicants. The committee uses “potentially,” because whether exposure to tobacco toxicants is reduced depends on the user’s behavior, such as frequency and intensity of use. Reduced exposure, however, does not necessarily assure reduced risk to the user or reduced harm to the population. Therefore, and in order to avoid misinterpretation, the committee will use the generic phrase “potential reduced-exposure products,” or PREPs, when discussing modified tobacco products, cigarette-like products (whether tobacco containing or not), or pharmaceutical products and medical devices (whether nicotine containing or not) developed for their tobacco harm reduction potential. Demonstration of exposure reduction is possible but at this time, demonstration of harm reduction is not. This conclusion is reiterated and supported in subsequent chapters. No tobacco-based PREPs other than conventional low-yield products have been used by enough consumers to assess health impact. The recent or forthcoming expansion of the test market for several new products, which are described in Chapter 4, and public statements by tobacco company executives suggest a new and critical opportunity for assessing harm reduction. The next few years may see an explosion of available tobacco or cigarette-like products that make some claim of harm reduction based on reduced tobacco or smoke content of one or more toxicants. Uncertainty and skepticism remains about the potential health benefits of PREPs. Key to the skepticism, in addition to the lessons learned from low-yield products, is concern that such products will discourage quitting in smokers who might otherwise have stopped using tobacco or will encourage new tobacco use. Evidence to support this concern is limited, however. Historical data suggest that people “switched down” to low-yield products due in part to health concerns, but the studies were not designed to determine whether those smokers would have quit tobacco use altogether had only high-yield products been available. Most PREPs will maintain nicotine addiction and there is little agreement in the tobacco control field that public policy should encourage products that maintain nicotine addiction. Worrisome as harm reduction might be to those who have studied the history and disappointments of low-yield cigarettes, PREPs are currently available and likely are here to stay. NICOTINE There is disagreement among tobacco control experts about the optimal content of nicotine in tobacco products. Whether nicotine addiction is harmful beyond supporting tobacco use and should, therefore, be the target of public health efforts is not a simple question. Nicotine has toxic properties (see Chapter 9), but they are far fewer and less serious than

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction those of other tobacco constituents. Some have proposed that nicotine should be removed from tobacco products in order to prevent addiction (Henningfield et al., 1998), decrease tobacco use, and thereby decrease exposure to the most toxic constituents in tobacco. The marketability of a nonaddicting tobacco product, however, is thought to be low. Nicotine has pleasurable or rewarding effects, in addition to its addictive properties. However, societal views of addictions per se surround the controversy. Retaining nicotine at pleasurable or addictive levels while reducing the more toxic components of tobacco is another general strategy for harm reduction (for a recent review of this issue, see Russell, in Ferrence et al., 2000). The tobacco industry reportedly would support some FDA regulation of cigarette products (Schwartz and Kaufman, 2000). Key to its acceptance is that there be no upper level for nicotine that is set so low as to effectively ban cigarettes (Schwartz and Kaufman, 2000). Experience with NEXT, a cigarette with extremely low nicotine levels that did not succeed in the marketplace, suggests that nicotine is one of the factors crucial to the success of a tobacco product. PHARMACEUTICAL PRODUCTS Modified tobacco and cigarette-like products are not the only potential strategies for harm reduction. Two classes of pharmaceutical products might provide an alternative to the less harmful cigarette for harm reduction. These two classes of drugs are nicotine products, of which there are several such as patch, gum, inhaler, and nasal spray preparations, and nonnicotine products. To date, only one product that does not contain nicotine has been approved by the FDA for tobacco cessation and is on the market—a slow-release bupropion preparation, Zyban. This has been approved by the FDA for short-term (up to six months) use for tobacco cessation and was subject to standard FDA review and approval. Chapter 4 includes a detailed description of such products and the FDA approval process. Early speculation that these products might be used on a long-term or continuing basis to reduce exposure to tobacco toxicants was supported by the observation that some people use them far longer than indicated in the FDA labeling and continue to smoke as well. It is possible that these smokers might decrease their tobacco use to a level that is less harmful than their prior tobacco use. Some smokers might cease using tobacco but use the pharmaceutical products on a long-term basis to help ensure abstinence. Claims by the manufacturers of usefulness for harm reduction short of cessation or for long-term maintenance would require FDA review and approval for either new indications or as new products. To date,

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction no drugs have been approved for use with such harm reduction claims. The health effects of pharmaceuticals used as PREPs include both the effects of the drug itself (both benefits and risks) and of any concomitant tobacco use. REGULATORY ISSUES AND AUTHORITIES This strong federal regulatory authority for nontobacco, pharmaceutical PREPs contrasts with that for conventional tobacco products and, possibly, tobacco-related PREPs. The FDA asserted in 1996 that conventional cigarettes and smokeless tobacco were nicotine delivery devices intended to affect the structure and function of the human body and thus fell under its jurisdiction. On March 21, 2000, the Supreme Court of the United States denied FDA jurisdiction over these products (Legal Information Institute, 2000). The Supreme Court majority opinion stated that it was never congressional intent for FDA to regulate tobacco and that the products did not fall under the Food, Drug, and Cosmetic Act or its amendments. FDA does retain the authority to regulate health claims regarding tobacco products. However, there is no precise definition of the term “health claim.” The Federal Trade Commission has regulatory authority over the advertising and marketing of tobacco products. The purpose of FTC authority, however, is to ensure consumers have opportunities to exercise informed choice. The FTC enforces a variety of federal antitrust and consumer protection laws. They seek to ensure that the nation’s markets function competitively and are vigorous, efficient, and free of undue restrictions. They work to eliminate acts or practices that are unfair or deceptive (FTC, 1999). Thus, the FTC has responsibility under various federal laws to ensure the proper display of health warnings in advertising and on packaging of tobacco products sold in the United States. Further, the agency collects and reports to Congress information concerning cigarette and smokeless tobacco advertising, sales expenditures, and the tar, nicotine, and carbon monoxide content of cigarettes (FTC, 1992). Other federal agencies have jurisdiction over tobacco (e.g., the Bureau of Alcohol, Tobacco, and Firearms and the Department of Agriculture) but not regarding health issues. No agency is responsible for ensuring that any standards are met in the manufacturing and composition of tobacco products. This disparity between strict regulation of nicotine replacement products (and Zyban) compared to tobacco products puts the safest form of nicotine administration at serious marketing disadvantage. The so-called unequal regulatory playing field has led to suggestions to raise regulatory standards for tobacco or to lower the regulatory stan

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction dards in terms of marketing, packaging, and over-the-counter availability of tobacco cessation and harm reduction pharmaceutical products. COMMITTEE CHARGE AND PROCESS Because of the staggering morbidity and mortality associated with tobacco use and because fewer than 10% of smokers who attempt to quit each year succeed, public health considerations suggest a need to study alternatives to cessation for some smokers. Purported harm reduction tobacco products have been introduced into the U.S. marketplace periodically over the last 50 years. There is a strong likelihood of increased marketing and more products in the near future (Philip Morris Incorporated, 2000). These products are often associated with marketing statements or claims interpreted by some as indicating less health risk than to conventional products. It is also possible that nicotine or other pharmaceutical products could be used on a long-term basis for harm reduction, either concomitant with decreased use of conventional tobacco products or by themselves for maintenance of tobacco abstinence. In anticipation of these issues, in 1999 the FDA asked the Institute of Medicine (IOM) to convene a committee of experts to formulate scientific methods and standards by which PREPs (pharmaceutical or tobacco related) could be assessed. Specifically, the committee was asked to answer several questions about harm reduction products. Where there are not yet answers, the committee was to determine the broad strategy by which the knowledge base should be assembled. For each product or class of product, four questions were asked: Does use of such a product decrease exposure to the harmful substances in tobacco? Is this decreased exposure associated with decreased harm to health? Are there surrogate indicators of this harm to health that could be measured in a time frame sufficient for product evaluation? What are the public health implications of tobacco harm reduction products? The first three questions are obviously necessary for regulatory review of PREPs for their ability to reduce the risk to an individual of tobacco-caused disease and for decision making by an individual about tobacco use. The fourth question is important to ensure the health of the public. That is, although a PREP might be risk-reducing for an individual’s health compared to conventional tobacco products, the availability of

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction PREPs might not be harm-reducing for the population. This could occur if tobacco users who might otherwise have quit do not, if former tobacco users resume use, or if some people who would not have otherwise initiated tobacco use do so because of perceptions that the risk with the “new” products is minimal and therefore acceptable. The committee was not asked to evaluate, and so did not debate, the merits of pursuing harm reduction. The committee was drawn by its charge necessarily and inevitably into considering the regulatory framework for products purported to reduce harm from tobacco use. First, regulation is a necessary precondition for advancing scientific knowledge on the effects of using these products, especially their impact on public health. Second, whether the public health impact will be beneficial is substantially dependent on the implementation of a comprehensive and carefully designed regulatory framework for these products. An expert committee was convened by the IOM and is the author of this report. The report is offered to the FDA, FTC, other relevant federal and state regulatory and policy bodies, Congress, scientists and health care professionals, tobacco and pharmaceutical industries, and—most importantly—the public, who will have to consider advertising and marketing information and make decisions about whether to use these products. The committee hopes the report will also be useful to similar groups in other countries, some of which are examining the harm reduction issue at present and to the global tobacco control community. Committee expertise includes clinical medicine, epidemiology, toxicology, pharmacology, behavioral sciences, regulatory policy, and public health. The committee met five times between December 1999 and August 2000. Three of the committee meetings involved open sessions, during which invited researchers, public health advocates, clinicians, and representatives of tobacco and pharmaceutical manufacturers presented relevant data and engaged in scientific discussions. Written submissions were encouraged and reviewed by the committee (see Appendix A for a listing of these presentations and submissions to the committee). The committee in part or as a whole reviewed thousands of articles from the scientific peer-reviewed literature, including original research, review articles, and reports of advisory bodies such as the office of the U.S. Surgeon General. All materials sent to the committee and those used in support of this report are listed in a public access file maintained by the National Research Council’s (NRC) Public Access and Records Office. This report, which contains a Preface, Executive Summary, and 16 chapters including this introduction, is divided into two sections. Section I contains background material, conclusions, and recommendations on surveillance implementation and general conclusions regarding the

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction committee’s charge. Chapter 2 reviews general principles of harm reduction. Chapter 3 discusses the historical record of harm reduction attempts with an eye toward lessons learned for the future. Chapter 4 discusses current products and strategies for tobacco harm reduction. Chapter 5 contains a summary of the technical evidentiary base, conclusions, and recommendations regarding the first three questions of the charge. Chapter 6 reviews the public health considerations of harm reduction, including conclusions and recommendations regarding surveillance and post marketing research. Chapter 7 provides an overview of conclusions regarding the implementation of a public health approach to tobacco harm reduction, including principles for regulating PREPs. Chapter 8 sums up section one with principal conclusions. Section II contains the technical evidentiary base summarized in Chapter 5. Chapters 9 and 10 describe the pharmacology of nicotine and the toxicology of tobacco. Chapter 11 discusses principles of exposure assessment. Chapters 12–16 discuss the evidence that harm reduction strategies might impact the major diseases associated with tobacco and nicotine use. APPLICATION OF RISK ASSESSMENT TO TOBACCO HARM REDUCTION Predicting human health risks from toxic exposures, such as those associated with occupational and environmental toxicants, frequently involves a risk assessment process such as that outlined in “Risk Assessment in the Federal Government” (NRC, 1983), a report produced at the request of the U.S. Food and Drug Administration. The risk assessment process outlined in the NRC report, sometimes referred to as “The Red Book,” includes four basic elements: hazard identification (Does the agent cause an adverse health effect?), dose-response assessment (What is the relationship between dose and incidence in humans?), exposure assessment (What exposures are currently experienced or anticipated under different conditions?), and risk characterization (What is the estimated incidence of the adverse health effect in a given population?). Hazard identification includes laboratory and field observations of adverse health effects resulting from exposures to specific agents. For dose-response assessment, if clinical or epidemiological data are not available, extrapolation from high-to-low-dose exposures and from animal to human doses in dose-response assessment is required. To determine

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction exposures, research based on field measurements, estimated exposures, and characterization of populations is required. The data required for the first three elements of the risk assessment process usually include in vitro and in vivo toxicology studies in animals, including dose-response studies; mathematical modeling; toxicokinetic studies in animals and human; other clinical studies in humans; and, if available, epidemiology studies in human populations. A synthesis of those three components leads to a risk characterization. This can be either qualitative or quantitative. Considerations that can affect the risk characterization are the statistical and biological uncertainties in estimating the health effects, the choice of dose-response or exposure assessments used, and a determination of targeted population for protection. The risk characterization is used to guide regulatory or other action for the purposes of risk management. This entails consideration of political, social, economic, and other technical (e.g. engineering) information with risk-related information. Value judgments are involved, such as the acceptability of risk and the reasonableness of the costs of control. Risk assessment is the link between research and decision making (risk management). Complex and conflicting scientific information must be presented in an organized manner such that its meaning and limits are clear to the risk manager. The more complex the science base and the more controversial the policy implications, the more a rational and explicit framework is needed. Tobacco harm reduction presents complex technical issues and controversial policy options. The committee has used the Red Book risk assessment paradigm in its approach to assessing the science base for tobacco harm reduction. Chapter 5 includes a discussion of the special challenges tobacco (and PREPs in particular) poses to risk assessment. Chapter 5 (and the chapters from Section II summarized in it) also contains the evidence that PREPS could affect each major tobacco-related disease. Each type of evidence is linked to the Red Book paradigm. The data gaps that currently prevent a quantitative risk characterization for PREPs are also described. Chapter 8, Conclusions, returns to the Red Book paradigm to organize the conclusions and recommendations of the report. This organization and synthesis demonstrates that each of the four steps in risk assessment and in risk management are informed by: the four specific questions posed by the committee (described above) as a means to answer its charge in order to provide regulatory, scientific, and medical guidance, the evidence reviewed by the committee in each of the disease-

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Clearing the Smoke: Assessing the Science Base for Tobacco Harm Reduction specific chapters (contained in Section II and summarized in Chapter 5), the principal conclusions of the committee (found in Chapter 8) related to the questions contained within the charge, specific recommendations of the committee related to a comprehensive surveillance system (Chapter 6) and regulatory principles (Chapter 7), and the research gaps identified (Chapter 5 and Section II). OPERATING PRECEPTS The committee introduces the rest of the report by laying out four fundamental operating precepts. The committee reiterates and reaffirms decades of overwhelming scientific evidence and the conclusions and recommendations of advisory bodies such as those that authored the Surgeon General’s reports, previous IOM and NRC committees, and international health experts such as the World Health Organization. Tobacco use causes serious harm to human health. Nicotine is addictive. The best means to protect individual and public health from tobacco harms are to achieve cessation, prevent initiation and relapse, and eliminate ETS exposure. A comprehensive and authoritative national tobacco control program, with harm reduction as one component, is necessary to minimize adverse effects of tobacco. REFERENCES 21 CFR 897.3 (1997) Cigarettes and smokeless tobacco (eff. 8–28–97): Subpart A-General Provisions. 27 CFR 290.11 (1997) Exportation of tobacco products and cigarette papers and tubes, without payment: Subpart B-Definitions. CDC (Centers for Disease Control and Prevention). 1993a. Cigarette smoking-attributable mortality and years of potential life lost-United States, 1990. Morbidity and Mortality Weekly Report 42(33):645–649. CDC (Centers for Disease Control and Prevention). 1993b. Smoking cessation during previous year among adults-United States, 1990 and 1991. Morbidity and Mortality Weekly Report 42(26):504–507. CDC (Centers for Disease Control and Prevention). 1994. Health objectives for the nation cigarette smoking among adults-United States, 1993. Morbidity and Mortality Weekly Report 43(50):925–930. CDC (Centers for Disease Control and Prevention). 1998. Selected cigarette smoking initiation and quitting behaviors among high school students-United States, 1997. Morbidity and Mortality Weekly Report 47(19):386–389.

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