Tobacco Documents Online

Report of the Surgeon General's Advisory Committee on the Health Consequences of Using Smokeless Tobacco April 1, 1986 Prepublication Copy

PREFACE This report discusses the health consequences of smokeless tobacco use. It constitutes a comprehensive review by an Advisory Committee to the Surgeon General of the available scientific literature to determine whether using smokeless tobacco increases the risk of cancer and noncancerous oral diseases and effects, leads to addiction and dependence, and contributes to other . health consequences. r AFTER A CAREFUL EXAMINATION OF THE RELEVANT EPIDEMIOLOGIC, EXPERIMENTAL, AND CLINICAL DATA, THE COMMITTEE CONCLUDES THAT THE ORAL USE OF SMOKELESS TOBACCO REPRESENTS A SIGNIFICANT HEALTH RISK. IT IS NOT A SAFE SUBSTITUTE FOR SMOKING CIGARETTES. IT CAN CAUSE CANCER AND A NUMBER OF NONCANCEROUS ORAL CONDITIONS AND CAN LEAD TO NICOTINE ADDICTION AND DEPENDENCE. The major overall conclusions of this report are the following: 1. It is estimated that smokeless tobacco was used by at least 12 million people in the United States in 1985 and that half of these were regular users. The use of smokeless tobacco, particularly moist snuff, is increasing, especially among male adolescents and young male adults. 2. The scientific evidence is strong that the use of snuff can cause cancer in humans. The evidence for causality is strongest for cancer of the oral cavity, wherein cancer may occur several times more frequently in snuff dippers compared to nontobacco users. The excess risk of cancer of the cheek and gum may reach nearly fiftyfold among long-term snuff users. 3. Some investigations suggest that the use of chewing tobacco may also increase the risk of oral cancer, but the evidence is not as strong and the risks have yet to be quantified. 4. Experimental investigations reveal potent carcinogens in smokeless tobacco. These include nitrosamines, polycyclic aromatic hydrocarbons, and radiation-emitting polonium: The tobacco-specific nitrosamines often have been detected at levels 100 or more times higher than Government-regulated levels of other nitrosamines permitted in foods eaten by Americans. 5. Smokeless tobacco use can lead to the development of oral leukoplakias (white patches or plaques of the oral mucosa), particularly at the site of tobacco placement. Based on evidence from several studies, a portion of leukoplakias can undergo transformation to dysplasia N and further to cancer. cn 0 6. Gingival recession is a commonly reported outcome of smokeless tobacco ~ use. ~, co 0 ~ v

7. A number of studies have shown that nicotine exposure from smoking cigarettes can cause addiction in humans. In this regard, nicotine is similar to other addictive drugs such as morphine and cocaine. Since nicotine levels in the body resulting from smokeless tobacco use are similar in magnitude to nicotine levels from cigarette smoking, it is concluded that smokeless tobacco use also can be addictive. Besides, recent studies have shown that nicotine administered orally has the potential to produce a physiologic dependence. . 8. Some evidence suggests that nicotine may play a contributory or sup- portive role in the pathogenesis of coronary artery and peripheral vascular disease, hypertension, peptic ulcers, and fetal mortality and morbidity. V1

Evidence that suggested a possible association between smokeless tobacco use and oral conditions in North America and Europe was not reported until 1915 when Abbe identified several tobacco chewers among a series of oral cancer patients and commented that smokeless tobacco use may be a risk factor for this cancer (6). In the late 1930's, Ahblom observed in Sweden that more patients with buccal, gingival, and "mandibular" cancers than with other cancers reported the use of snuff or chewing tobacco (7). In the United States, case reports of oral cancer among users of snuff or ' chewing tobacco appeared in the early 1940's (8). The first epidemiologic study of smokeless- tobacco was not conducted until the early 1950's (9). Since that time, several scientists have described a pattern of increased risk of oral cancer among smokeless tobacco users. Investigations of other possible health effects of smokeless tobacco use (e.g., noncancerous oral effects, addiction, and other physiologic consequences) are more recent subjects of scientific inquiry that have been undertaken pri- marily in the past two decades. A brief review of the health consequences of smokeless tobacco was presented in the 1979, Surgeon General's report on smoking and health (10). Since that review, the results of additional studies addressing the role of smokeless tobacco in health have become available and thus provide the basis of this current comprehensive review. REVIEW METHODS For the purpose of evaluating the scientific evidence to be included in this report, the Advisory Committee called upon the same criteria to determine causality as have been used for a number of Surgeon General's reports on smok- ing for the past two decades. The following criteria were used as the primary guidelines for assessing whether any associations between smokeless tobacco use and each of the disease areas or health condition's under examination were likely to be causal in'nature: • Consistency of the association-similar observations by multiple investigators in different locations and situations, at different times, and using different methods of study. • Strength of the association-high ratio of disease rate for the population exposed to the suspected risk factor compared to the population unexposed to the risk factor. • Specificity of the association-associations with the exposure exist for a specific or limited set of diseases, and associations with the disease exist for a specific or limited set of exposures. • Temporal relationship of the association--exposure to, the suspected etiologic factor precedes the disease. • Coherence of the association--epidemiologic observations are conso- nant with all else that is known about the disease. XV11

1 I l i i k V J: V!~. a=. f r In addition to these criteria, the general principles employed by the Inter- national Agency for Research on Cancer (IARC)* in evaluating the carcinogenic risk of chemicals or complex mixtures (table 1) were used as needed to supple- ment the primary causation criteria (11). OVERVIEW r The use of smokeless tobacco products in the United States was widespread until the end of the 19th century. With the advent of antispitting laws, loss of social acceptability, and increased popularity of cigarette smoking, its use declined rapidly in this century. However, recent national data indicate a resurgence in smokeless tobacco habits with more than 12 million persons - estimated as users of some form of smokeless tobacco in 1985. An upward trend in use is emerging, particularly among young males. Given the evidence that smokeless tobacco is regaining popularity, seri- ous questions have been raised about its adverse health effects. Most notably, this behavior has been linked to cancer, specifically, oral cancer. Analytic epidemiologic studies now indicate that the use of oral snuff increases the risk of oral cancer several fold and that among long-term snuff dippers the excess risk of cancers of the cheek and gum may reach nearly fiftyfold. This conclusion is consistent with the judgment of a recent working group of the IARC, which assessed the carcinogenic risk associated with tobacco habits other than smoking (11). The conclusion that smokeless tobacco causes cancer results from several lines of evidence: the presence of high levels of carcinogens in smokeless tobacco; the metabolic conversion of products of smokeless tobacco into geno- toxic agents; the consistency of the oral cancer-smokeless tobacco association across epidemiologic investigations conducted in diverse locations; the trend in increasing oral cancer risk with duration of exposure; the strength of the association with oral cancer; and the occurrence of the highest risks for cancers at the anatomic sites where the tobacco, exposures are the greatest. In addition, a number of clinical observations and studies show an asso- ciatioa between smokeless tobacco use and some noncancerous and precancerous oral health conditions. The development of a portion of oral leukoplakias in both teenage and adult users can be attributed to the use of smokeless tobacco. The risk of developing these leukoplakic lesions increases with increased ex- posure, and a number of studies now suggest that some snuff-induced leukoplakias can undergo transformation to dysplasia and further to carcinoma. The evidence concerning the adverse health effects of smokeless tobacco use on other oral soft and hard tissues is only suggestive at this time. *The IARC was established in 1965 by the World Health Assembly as an indepen- dently financed organization within the framework of the World Health Orga- nization. It conducts a program of research concentrating particularly on the epidemiology of cancer and the study of potential carcinogens in the human environment. 2501442804 xviii

4R .....~., ..~ .aa....n.' ..e..-.r. ...-~.•-..:.h:.i..^.r.r:•r±r..n'w:e.~w^..,Y•..~~...~.~~:.~ i .. . . ~ ~ ..... .. ±,~.r~~ _ . .. . .... .. ~- ,.... r.. ..:aa. . .•-i:. .. ~ .. •a•.c•.::.i .~ . . to provide more accurate responses (47-49). Biochemical validation was used in 14 of the 17 subsamples reported in table 13. in use (34,42,43). Most studies do not distinguish between snuff and chewing tobacco. In reports where the two have been separated, both substances were found to be Rates of smokeless tobacco use were consistently higher among males•than females. This difference is especially marked when more precise classifica- tions for regular use are employed. While substantial numbers of adolescent • females report having tried smokeless tobacco at least once, very few use it on a regular basis (33-35,37,39,46). The use of smokeless tobacco by youth was generally higher in rural than urban areas, in small communities, and in areas where there is a tradition of smokeless tobacco use (34,37,46). However, high rates of use have also been reported in large metropolitan areas as well (37,40,46). 0 Table 14 summarizes data on smokeless tobacco use by ethnic groups col- lected by investigators using standardized questions (46). To date, little information has been available on smokeless tobacco use by nonwhites, and some early research suggested that minority'youth were not taking up the practice (42). In these studies, however, Hispanic youth showed rates of smokeless tobacco use comparable to whites, and Native American rates were consistently higher. In most locales, use was less common among Asians and blacks. Nationally, black college students are less likely to use snuff than are white college students (table 6). Prevalence estimates for smokeless to- bacco use by black adults, however, have equaled or exceeded those of whites (tables 5 and 11). The likelihood of using smokeless tobacco appears to increase with age as well as over time (32-35,37,42,46). Only one study has collected both cross-sectional and longitudinal data. Hunter and her colleagues assessed tobacco use by children in Bogalusa, Louisiana, in 1976-77 and again in 1981- 82 (42). The use of both snuff and chewing tobacco increased over time within age categories, within age cohorts, and across age categories (table 12). A decrease in use was observed in the oldest age category, 16-17 years old, but has not been seen in other locales (tables 12 and 13). The decrease may reflect age-related changes in normative behavior particular to that area or a cohort effect. Peer and family members are found consistently to be important influences on smokeless tobacco use by children and adolescents. Young users of smokeless tobacco have more friends who also use smokeless tobacco (34-36,39,45) and may themselves identify friends' encouragement as a reason for use (35,44). Users of smokeless tobacco are also more likely to have family members who themselves use smokeless tobacco (34,36,45) and encounter less parental disapproval for the practice (31,34). In a special National Program Inspection study prepared by the Office of the Inspector General of the Department of Health and Human Services, young current and former users of smokeless tobacco were interviewed in depth (50). Two hundred ninety students in junior and senior high schools from 16 States i 1-7

volunteered to participate. A11 had used smokeless tobacco on a weekly or daily basis. While this study was not designed to provide prevalence estimates, it provides useful information about the attitudes and practices of some adolescent smokeless tobacco users. Over 90 percent of these respondents used snuff exclusively, and over 55 percent indicated that they would have strong cravings if they tried to quit. On the average, this group reported first trying snuff at age 10 and beginning regular use by age 12. Fifty percent cited pressure from friends as their primary reason for initiating use, but continued use was most often attributed to enjoyment of taste (64 percent) and habit strength ("being hooked," 37 per- dt d: at s cent). Over 85 percent thought that dipping and chewing can be harmful to ~ health, but less than 55 percent considered regular use to present a moderate or severe risk. .~ ~ ~ CONCLUSIONS I 1. Recent national data indicate that over 12 million persons used some form of smokeless tobacco (chewing tobacco and snuff) in 1985 and that approxi- mately 6 million used smokeless tobacco weekly or more often. Use is increasing, particularly among young males. 2. The highest rates of use are seen among teenage and young adult males. A.recent national survey indicates that 16 percent of males between 12 and 25 years of age have used some form of smokeless tobacco within the past year and that from one-third to one-half of these used smokeless tobacco at least once a week. Use by females of all ages is consistently less than that of males; about 2 percent have used smokeless tobacco in the last year. 3. State and local studies corroborate the national survey findings. The prevalence of smokeless tobacco use by youth and young adults varies widely by region, but use is not limited to a single region. In'several parts of the country, as many as 25 to 35 percent of adolescent males have indicated current use of smokeless tobacco. RESEARCH NEEDS More systematic and detailed national and local surveys on smokeless tobacco should be conducted.* National probability sample surveys need to be supplemented with surveys of suspected "hot spots" to detect the extent of high-risk areas in the country and the prevalence of use in these areas. Standardized methods are essential to facilitate appropriate comparisons among data. The current state of assessment is similar to the early days of research on cigarette smoking before standardized formats for assessment of prevalence and quantificatioa of dosage became available. Accurate and repro- *The 1986 OSH Adult Use of Tobacco Survey will address many of the items listed below N Ln 0 . ~ ~ .~ ~ 1-8 3