SMOKING AND SMOKING CESSATION
Magnitude of the Smoking Problem
Biologic Basis for Nicotine Addiction
Stages in Tobacco Use and Smoking Cessation
Evaluating the Smoker
Smoking causes dysfunction and disease in virtually every organ of the human body. It is also a source of frustration to the physician, who feels powerless in the face of a habit that is deeply ingrained in the patient and that, despite a massive and largely successful public health campaign, is still condoned and even enshrined by segments of society. This chapter is designed to give an overview of the dimensions of the problem of smoking, to convey an understanding of the nature of tobacco and nicotine, and to provide the foundations for a clinical approach to the smoker.
MAGNITUDE OF THE SMOKING PROBLEM
Smoking remains the most common preventable cause of death in the United States. Smoking claims 450,000 lives annually, as many deaths as are caused by alcohol, cocaine, heroin, suicide, homicide, motor vehicle accidents, fire, and AIDS combined. Smoking doubles the overall mortality rate and is responsible for 30% of all deaths in the United States, including 90% of deaths due to lung cancer, 35% of all cancer deaths, 21% of deaths due to coronary heart disease, and 90% of deaths due to chronic obstructive lung disease. Smoking and the use of smokeless tobacco are also the major cause of cancer of the oral cavity and cancer of the esophagus, and they contribute to the deaths from cancer of the pancreas, cancer of the urinary tract, peripheral vascular disease, and cerebrovascular disease. Smoking also plays a significant role in the development of peptic ulcer disease and infectious respiratory disease and compounds the complications associated with diabetes.
Because women started smoking in large numbers more recently than men, their death rate from smoking has been lower, but the rate is catching up to that of men. Whereas the age-adjusted mortality rate from smoking rose 18% for men from 1973 to 1989, it rose 118% for women. Smoking exposes women to the same risks as men and also increases their risk of cancer of the cervix and osteoporosis. Smoking advances the age of menopause, causes premature aging of the skin, and increases the incidence of complications of stroke associated with the use of oral contraceptives. Smoking in pregnancy leads to postmature births, carriages, dynamicbirths, and heavy-birth-weight babies.
Smoking causes death, disease, and disability not only in smokers but also in those exposed to environmental tobacco smoke. Parental smoking, for example, provokes pneumonia, bronchitis, and middle-ear effusions in children, reduces their lung function, and places them at increased risk of asthma. Smoking by spouses increases the incidence of lung cancer in nonsmoking partners. Environmental tobacco smoke has been estimated to lead to 50,000 deaths due to cancer and coronary heart disease annually in the United States. The direct medical costs associated with smoking have been estimated conservatively at $53 billion annually. The total cost of smoking probably exceeds $100 billion annually.
Despite a massive campaign to inform the public of the hazards of smoking and despite increasing restrictions on smoking in the workplace and in public places, 47 million Americans, or 27.0% of men and 22.6% of women, were still smoking in 1995. In 1965, however, 42.4% of the population smoked, and 50% of all adults who have ever smoked have quit, a success unparalleled in the annals of public health. Furthermore, 70% of smokers responding to a 1994 survey of the Centers for Disease Control and Prevention expressed a desire to quit and have made at least one serious attempt to quit. Unfortunately, the addictive nature of nicotine, the strength of a habit reinforced by a million puffs taken over the career of a smoker, intense marketing by the tobacco industry, and the ready availability of tobacco products conspire to allow only 2.5% of smokers to succeed in quitting in any given year. Even the simplest intervention by the physician can double the success rate. Seventy percent of smokers consult their physicians at least yearly, but 30% of those who consult their physicians are not even advised to stop smoking, and only a few smokers receive the sustained, organized, and appropriately intense counseling and support their devastating habit deserves.
BIOLOGIC BASIS FOR NICOTINE ADDICTION
The psychoactive properties of tobacco were an important part of the rituals and healing practices of the peoples indigenous to the Americas for millennia. Ancient Mayan manuscripts vividly depict an underworld populated by gods smoking tobacco rolled into cones resembling cigars. Acute intoxication was deemed to have a transcendental purpose and was achieved not only through smoking but also through chewing, drinking, licking, and purging. European discoverers turned tobacco into an important commodity that shaped the economy of the American colonies and laid the foundation for today’s giant transnational tobacco companies. The use of tobacco, however, was condemned and even banned for religious and esthetic reasons as early as the sixteenth century.
The advent of the cigarette-making machine in 1884, the invention of the safety match, and the creation of a positive, healthful image associated with smoking broadly popularized the use of tobacco. Acute intoxication was replaced with the problems of long-term addiction and chronic disease. In 1930, lung cancer was listed for the first time as a cause of death in the vital statistics of the United States. Tobacco has undergone many changes. It has been bred into many different varieties that make each specifically suitable to a particular taste or mode of administration. Tobacco is predominantly smoked as cigarettes, but it is also smoked as cigars or in pipes. There has been a resurgence of the use of smokeless, or chewing, tobacco, especially by adolescents.
There are four commonly used types of tobacco: flue-cured, light air-cured, dark, and oriental. Flue-cured tobacco has a high sugar and a low nitrogen content and produces an acidic smoke that prevents the absorption of nicotine in the oral cavity and makes more nicotine available for absorption through the lung. It is therefore a major ingredient of cigarettes. Light air-cured tobacco has a cellular structure that facilitates the absorption of various fillers and flavorings. For this reason it is used as a carrier of additives in cigarettes. Dark tobacco is fermented and thus has a low sugar and a high nitrogen content and produces an alkaline smoke that favors the absorption of nicotine in the oral cavity. Dark tobacco is preferred in pipes and cigars, which are puffed rather than inhaled, and in smokeless tobacco, which is chewed. Oriental tobacco is prized for its aroma.
Tobacco contains an estimated 4,000 compounds, including many that are pharmacologically active, toxic, mutagenic, and carcinogenic. There are several pharmacologically active alkaloids in tobacco, but nicotine is the most important. Among the toxic substances found in tobacco smoke are carbon monoxide, hydrogen cyanide, and ammonia. Forty-three definite carcinogens have been identified in tobacco smoke, including polynuclear aromatic hydrocarbons, N-nitrosamines, and inorganic compounds, such as arsenic and chromium. The carcinogens are targeted to the oral cavity when tobacco is chewed, to the oral cavity and the esophagus when pipes or cigars are puffed, and to the lung and remote organs when cigarette smoke is inhaled.
During the manufacture of cigarettes, cigars, and pipe and chewing tobacco, numerous ingredients are added to the tobacco leaf. These include sugars and licorice, which alter the flavor of the cigarette; glycerol and diethylene glycol, which retain moisture; menthol to reduce throat irritation; inorganic salts, which change the burning characteristics of the tobacco; and several oils to enhance the aroma. As a result, there are hundreds of tobacco products on the market targeted to every segment of the population. But all are ultimately designed to deliver nicotine into the system and to reinforce the addictive properties of nicotine.
PSYCHOPHARMACOLOGIC PROPERTIES OF NICOTINE
In the early 1800s, Cerioli and Vauquelin isolated an oily essence of tobacco; they named it “nicotianine” after Jean Nicot, who sent tobacco seeds from Portugal to the French court at the end of the sixteenth century. Nicotine is by far the major, but not the only, psychoactive alkaloid found in tobacco. It is a tertiary amine composed of a pyridine and a pyrrolidine ring. It is a weak base with a pKa of 8.0. In its pure form, it is a clear, volatile, alkaline liquid that has the smell of tobacco and turns brown when exposed to air. The concentration of nicotine varies in different types of tobacco leaves, but after the manufacturing process, the nicotine content of different brands of cigarettes is remarkably constant (about 8.4 mg). The level of nicotine delivered to the smoker, however, varies from 0.1 to 1.9 mg per cigarette, depending on the density of the tobacco in the cigarette and the presence of filters and designs that favor dilution of the smoke that is inhaled.
The temperature at the tip of a burning cigarette is 884°C, allowing for the distillation of nicotine along with other components into a vapor that is easily inhaled and rapidly absorbed across the alveolar surface. After absorption, nicotine is taken up rapidly by the brain and slowly distributed to other tissues. Nicotine is metabolized primarily in the liver to cotinine and nicotine oxide. Nicotine and its metabolites are excreted through the kidney. The half-life of nicotine in blood after tissue uptake is about 120 minutes. This means that during regular smoking, nicotine levels rise over 6 to 8 hours before reaching equilibrium and persist for 8 hours after cessation.
The effects of nicotine felt by the smoker are mediated through both the central and peripheral nervous systems. Nicotine, for example, affects various components of the neuroendocrine system and stimulates the release of anterior and posterior pituitary hormones. It binds to specific receptors in the brain and stimulates the release of acetylcholine in the cerebral cortex. It also causes the release of catecholamines from the adrenal medulla and from sympathetic nerve endings and of acetylcholine in the myenteric plexus of the gastrointestinal tract.
Nicotine, like heroin and cocaine, and far more often than ethanol, causes dependence. Criteria for dependence are the compulsive use of a substance, even when the harmful effects are known; the presence of psychoactive effects; the potential for reinforcement of behavior leading to use of the substance; the presence of physical signs of defense manifested through withdrawal symptoms; and the development of tolerance indicated through the increasing use of the substance to achieve a desired end point. Nicotine meets all these criteria. It is psychoactive because it has effects on mental function and mood. At blood levels most commonly found in smokers, it acts as a euphoriant, an anxiolytic, and a stimulant. More important, nicotine acts as a positive reinforcer, making one dose of nicotine, or one puff, or one cigarette, lead to the next. Abstinence from nicotine leads to a constellation of withdrawal symptoms that together constitute a craving for nicotine. Nicotine, like other psychoactive drugs, produces tolerance. The typical new smoker, therefore, gradually increases cigarette consumption over several years before reaching a plateau.
It was long thought that smokers regulated their smoking to maintain a set level of nicotine in the blood and brain. The basic impetus for maintaining that level was believed to be the avoidance of symptoms of nicotine withdrawal. It is now thought, however, that nicotine use is also governed by a far more complex process of learning and conditioning. A smoker, in other words, learns to smoke in response to specific stimuli, initially because of a perceived benefit and then merely as a conditioned response. These stimuli may be general, such as stress or boredom, or specific, such as the ringing of a telephone, sexual arousal, or completion of a meal. The resulting stereotypical pattern of tobacco use is another important marker of dependence. Treatment of nicotine addiction must be directed to both physical dependence and conditioning.
STAGES IN TOBACCO USE AND SMOKING CESSATION
Tobacco use is often thought of as a career that typically spans decades and runs a circuitous route from experimentation to quitting. No single factor governs the career of tobacco use: it is determined by the complex interaction of the psychopharmacologic properties of nicotine, the psychological makeup of the smoker, and, perhaps most important, the surrounding cultural, social, and economic setting. Several stages have been described in the smoking career: experimentation, initiation, and regular or habitual use. Smoking typically begins during childhood or adolescence. Regular or habitual smoking usually starts during the transition from adolescence to adulthood. Of those who experiment, one-third to one-half go on to smoke habitually. Contrary to the popular belief that early experimentation is merely a rite of passage, it is more likely to lead to habitual smoking than later experimentation. Habitual smoking is more common among persons who are impulsive, extroverted, and subject to depression. Smoking is also more common among those who have a low level of academic achievement and among those whose parents and peers smoke. A higher degree of concordance for smoking status among monozygotic than among heterozygotic twins suggests that there also may be genetic factors involved in establishing the smoking habit.
Tobacco marketing may also be a major influence on smoking initiation and habitual use. The tobacco industry spends an estimated $3.25 billion yearly on advertising and marketing, generally targeted to specific groups. The Joe Camel character, for example, is readily recognized by children. Marlboro cigarettes are the choice of adolescent boys and girls. Virginia Slims, on the other hand, are targeted to young women, many of whom smoke as a means of avoiding weight gain. Much advertising also appears to be directed at those who have quit smoking by emphasizing previous triggers of smoking. Smoking behavior is further complicated by social factors that enhance or deter smoking.
Recent rises in the excise tax on tobacco have shown that the cost of tobacco may be an important deterrent in the use of tobacco, particularly by children and teenagers. Like the development of the smoking habit, it is useful to think of smoking cessation not just as a single event but as a cyclic process with five stages: precontemplation, contemplation, action, maintenance, and relapse. In precontemplation, the smoker is not yet thinking of quitting; he or she may be unwilling, unaware, or discouraged from considering smoking cessation and may be defensive about smoking. Contemplation occurs as the smoker actively considers smoking cessation. At this stage, he or she seeks information and is typically concerned about smoking. Action occurs when the smoker takes steps to stop smoking. The smoker typically develops various strategies to prevent or overcome the temptation to smoke. Maintenance involves ongoing efforts to refrain from smoking after the smoker has achieved abstinence for about 6 months. Relapse, unfortunately the norm in smoking cessation, occurs when the smoker fails to maintain abstinence after quitting. Because smokers typically make many attempts at cessation before succeeding permanently, they may find themselves in various parts of the cycle several times during their smoking careers. Identifying the stages is useful because each requires a different intervention by the health care provider.
EVALUATING THE SMOKER
Because of the devastating impact of smoking on health, determining the smoking status should be as routine a part of every contact with a patient as measuring the vital signs. A more detailed evaluation geared to prescribing a specific smoking-cessation method should include measurement of the duration and severity of the smoking habit, identification of any symptoms or illnesses exhibited by the smoker that may be attributable to smoking, assessment of the smoker’s readiness to quit, a history of previous attempts to quit, and identification of personality variables and other internal or external factors that can facilitate or hinder quitting and not relapsing.
DURATION AND SEVERITY OF SMOKING HABIT
The longer and the more packs of cigarettes per day a smoker has smoked, the greater the impact on health, the need for smoking cessation, the likely resistance to quitting and not relapsing, and the necessity for intensive support during cessation. The Fagerstrom Tolerance Questionnaire (Fig. 33.1) is a simple, useful measure of the severity of physical dependence to nicotine. An urgent need to smoke within 30 minutes of waking up appears to be the most important indicator of severe physical dependence.
FIGURE 33.1. Questionanaire for identifying the addicted smoker. (Modified from Fagerstrom K–O. Measuring degree of physical dependence to tobacco with reference to individualization of treatment. Addict Behav 1978;3:235, with permission.)
SYMPTOMS AND ILLNESSES ATTRIBUTABLE TO SMOKING
Evidence of heart disease, in particular, and of other diseases attributable to smoking to a lesser extent are among the most potent motivators for smoking cessation.
READINESS TO QUIT
All smokers should be advised to stop smoking, and all smokers should be told clearly of any adverse effects that smoking has had on their health. Otherwise, it is best to tailor advice to the specific stage the smoker is in. Those in the precontemplation stage, for example, should be given information about the effects of smoking on health, which may motivate them to move to the next stage. They should be asked to read these materials carefully and should be questioned about them at a follow-up visit. Smokers in the contemplation stage should be given information about specific cessation methods and should be encouraged to set a “quit date.” Smokers in the action stage should be given maximal support in the form of behavioral techniques and pharmacologic agents to help them withstand the urge to smoke.
Personality Variables and Internal Factors
Rebelliousness, impulsiveness, and “identity assertion” in adolescence and adulthood have traditionally been viewed as major determinants of smoking. They are now seen as modifiers of other forces that favor change. Self-confidence and a sense that one’s actions can be effective, or the attribution of success to oneself rather than to others, are important predictors of success in smoking cessation that should be nurtured. A negative attitude or depression may be an obstacle to permanent abstinence from smoking, particularly if the euphoriant properties of nicotine have been used to combat depression.
Fear of weight gain is an important obstacle to smoking cessation and continued abstinence for many smokers. Appetite and hunger are common withdrawal symptoms after smoking cessation. Six months after cessation, men will typically have gained 9 pounds and women 10 pounds; greater weight gains are occasionally encountered. It is important to anticipate changes in weight and to develop appropriate strategies to prevent relapse of smoking. It should be stressed to the patient that the health benefits of smoking cessation far outweigh the risks associated with the usual weight gain.
The presence of a nonsmoking environment, beginning in the physician’s office and also at home and work and during leisure activities, is an important contributor to success in smoking cessation. Conversely, continued smoking by family and peers can be major obstacles that require specific, predetermined coping strategies.
Most smokers who have quit have done so without any obvious outside intervention. As the number of smokers in the population declines, however, an increasing number will be highly addicted to nicotine; these are the ones most in need of more intensive support and more specific cessation methods. Smoking-cessation methods can be classified on the basis of the intensity of the intervention and whether pharmacologic agents are used. Every smoker should be individually evaluated to determine the most appropriate smoking-cessation method. The patient’s preference and his or her experience of previous attempts at quitting play a key role in choosing a specific cessation method.
Helping patients to quit smoking on their own may be the most cost-effective cessation strategy. Only 10% to 15% are likely to remain abstinent from cigarettes at 1 year, but 60% will succeed after repeated attempts. Minimal intervention typically includes providing self-help materials, such as the American Lung Association’s Freedom from Smoking self-help manuals; setting a specific quit date; and offering brief counseling and follow-up to identify and deal with any obvious obstacles to smoking cessation.
More intensive smoking-cessation programs are indicated for smokers who want added support, those who have previously tried to quit and have been unsuccessful, those whose dependence on nicotine and smoking seem more intense, and those who lack sufficient self-confidence and external support. Intensive smoking-cessation programs may take the form of clinics organized by such voluntary health agencies as the American Lung Association, local hospitals, or employers; for-profit smoking-cessation programs; or individual therapy with physicians or other health-care professionals. In addition to providing health information that can motivate the smoker to quit, virtually all rely on behavior-modification techniques, such as the following.
Temptation management: careful identification of the time, place, and reason for smoking each cigarette and the development of avoidance and mitigation strategies to reduce the temptation to smoke
Cue extinction: deconditioning by purposefully avoiding smoking during exposure to cues that would normally lead to smoking
Contingency management: designation of concrete rewards to be earned for achieving specified goals or reaching specified landmarks during the action stage of smoking cessation
Aversive techniques, used in some research and commercial smoking-cessation programs, typically consist of rapid smoking of a series of cigarettes with frequent inhaling and with holding of smoke in the mouth to produce dizziness and nausea. Aversive techniques are effective but are infrequently used because of a fear, probably unfounded, of adverse health effects. In the past, electric shock has been used as an aversive stimulus, but it is applied rarely today. Hypnosis has been the subject of controversy and may or may not be effective. There is also little scientific evidence to support acupuncture as an adjunct to smoking cessation.
Pharmacologic agents have been used in the treatment of various forms of substance abuse because they can provide relief of withdrawal symptoms, serve as blockers or replacements, and produce aversion to the ingestion of a substance. Pharmacologic agents increase the likelihood of success in smoking cessation when used in combination with an organized behavior-modification program and should readily be offered to all but very light smokers.
Nicotine substitution in the form of nicotine polacrilex (gum), transdermal nicotine (patch), nicotine inhalers, or nicotine sprays is effective as an adjunct to a behavior-modification program, particularly for smokers who show a high degree of physical dependence to nicotine (as measured, for example, by the Fagerstrom Tolerance Questionnaire). Nicotine gum requires careful instruction in proper use, such as the need to avoid acidic beverages that can prevent absorption of nicotine and a proper way of chewing. Transdermal nicotine has the advantage of once-daily dosing, greater social acceptability than chewing gum, and the availability of various doses that can be tailored to each patient. The nicotine inhaler is said to have the advantage of reproducing the hand-to-mouth ritual of smoking. All forms of nicotine replacement have the potential of causing further nicotine dependence, but the benefits of smoking cessation far outweigh that risk.
Bupropion is an antidepressant that has been shown to decrease the desire for cigarettes. It is an effective alternative to nicotine substitution therapy. Clonidine is effective for the short-term relief of symptoms of nicotine withdrawal. Lobeline is a chemical analogue of nicotine, but its effectiveness as a form of replacement therapy remains unproved. Mecamylamine is a noncompetitive nicotine antagonist that has been tried as an agent to prevent the reinforcing effects of nicotine. Side effects at the high doses that have been used, however, have proved prohibitive. Silver nitrate mixes with a smoker’s saliva to produce an unpleasant taste, but it has not been proved effective as a form of aversion therapy in supporting abstinence.
Smoking has a devastating impact on health. Smoking cessation is difficult because of the addictive nature of nicotine and the continued social acceptance of smoking. The use of behavior-modification techniques and pharmacologic agents greatly increases the likelihood of success in quitting. If every physician and other health care practitioner were familiar with these tools and used them, the number of smokers who quit every year could double.
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