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Helping parents to stop smoking: which interventions are effective?
PAEDIATRIC RESPIRATORY REVIEWS (2001) 2, 222–226 doi:10.1053/prrv.2001.0144, available online at http://www.idealibrary.com on
MINI-SYMPOSIUM: SMOKING: EFFECTS ON THE PAEDIATRIC LUNG
Helping parents to stop smoking: which interventions are effective? T. Lancaster, L. Stead and S. Shepperd Department of Primary Health Care, University of Oxford Institute of Health Sciences, Old Road, Headington, Oxford OX3 7LF KEYWORDS smoking cessation, tobacco smoke pollution, nicotine replacement therapy, bupropion (Zyban).
Summary Parental smoking increases children’s risk of respiratory illness. Encouraging parents not to smoke in the home helps, but stopping smoking altogether is more effective in reducing children’s exposure. The prevalence of smoking increases with higher levels of social disadvantage and is therefore a major contributor to widening inequalities in health. Randomised trials have shown that adults can be helped to stop with simple advice from health professionals, behavioural support, nicotine replacement and antidepressants. ° C 2001 Harcourt Publishers Ltd
INTRODUCTION Exposure of children to passive smoking increases the risk of respiratory tract infections, otitis media, asthma and the sudden infant death syndrome.1 Parental smoking is the most important source of this exposure. One strategy for reducing children’s exposure to smoking is to ban smoking in the home. Programmes aimed at persuading parents not to smoke in the home can reduce exposure,2 and may lead to fewer children taking up smoking.3 However, analysis of cotinine levels at a population level has shown that smoking cessation by parents is a more effective way of reducing children’s exposure. In a study of non-smoking secondary schoolchildren in the United Kingdom, almost all the decrease in cotinine concentrations was accounted for by parents giving up, rather than restricting, smoking.4 Children of parents who give up smoking are also less likely to initiate the habit themselves.5 Hence, helping adult smokers to stop is important for their future as well as their current health, reducing the risk that they will die prematurely of cancer, respiratory or cardiovascular disease. Although some smokers quit without formal help, an increasing number succeed only after receiving some Correspondence to: Dr Lancaster, Clinical Reader and coordinating editor, Cochrane Tobacco Addiction Review Group. E-mail: [email protected] 1526–0550/01/030222 + 05 $35.00/0
form of support or treatment.6 There are a growing number of interventions advocated to help people to quit smoking, including behavioural, pharmacological and complementary therapies. The purpose of this review is to provide information to health professionals caring for children about the effectiveness of interventions to help smoking parents to stop.
METHODS The Cochrane Tobacco Addiction Review Group aims to identify and review data from randomised trials about interventions for preventing and reducing smoking. This review draws on the database of studies on smoking maintained by the group. Our conclusions about the effectiveness of interventions are based, wherever possible, on the findings of randomised trials and systematic reviews of randomised trials.7
WHY DO PEOPLE SMOKE AND WHY DO THEY STOP? Smoking is sustained by a complex interaction of social, psychological and biological factors, which find a common pathway in addiction to nicotine. Social factors appear to be of increasing importance. In the United Kingdom, the overall prevalence of smoking has fallen substantially in ° C 2001 Harcourt Publishers Ltd
HELPING PARENTS TO STOP SMOKING: WHICH INTERVENTIONS ARE EFFECTIVE?
the past 20 years (between 1973 and 1996 it fell from 53% to 29% in men and from 42% to 28% in women).8 However, these encouraging data hide a widening disparity between different social classes. While rates among the most affluent have fallen by more than 50% in Britain over 20 years, they have not decreased at all among the most deprived. In the United Kingdom, the likelihood that an individual will smoke is greater in lower occupational class groups, of lower educational attainment, those living in rented housing, without access to a car, who are unemployed and in overcrowded accommodation. The risk of smoking is also increased in those who are divorced, separated or lone parents. It is particularly high in people who are homeless, heavy users of alcohol or mentally ill.8 Among the most disadvantaged sectors of British society over 80% of adults smoke. These disparities contribute in turn to widening inequalities in health status between the social classes. The pattern is similar in other countries in which the tobacco epidemic is mature. Meanwhile, in many less affluent countries, historically low rates of smoking are increasing, fuelled by advertising that associates smoking with perceptions of increasing prosperity.9,10 Peto and Lopez11 have estimated that current patterns of cigarette smoking will cause about 450 million premature deaths world-wide in the next 50 years. Many of these deaths will occur in societies where life expectancy is already reduced by other poverty related diseases of nutrition and infection. If smoking is mainly a social issue, then a large part of the solution lies in improving the environment of those who smoke, by providing higher incomes, better housing and improved education. However, this long-term strategy needs to be supplemented by shorter-term solutions. Smokers who give up before middle age shed almost all the excess risk of mortality associated with smoking (and produce immediate benefits for their children). Peto and Lopez have estimated that a reduction of 50% in current smoking would avoid between a third and a half of the premature deaths forecast for the first half of the current century.11 These health benefits can only be achieved by helping current smokers to give up.
INTERVENTIONS Advice from health professionals The simplest way for health workers to help people to give up smoking is to offer them advice. Simple advice from doctors during routine clinical care has been studied in 31 randomised trials including over 26 000 smokers. A systematic review of these trials showed that advice consistently increases the number of people who stop, by about one and a half to two times.12 The effect of advice is probably to motivate a quit attempt, rather than to increase the chances of a quit attempt succeeding.13 Therefore, advice will usually be more effective when it
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is linked to further support and treatment for nicotine dependence. Little is known about the ideal content of the advice. However, there is both theoretical and practical validity to an approach based on an assessment of the patient’s motivation to stop.14 A simple message of advice will be appropriate for someone who is not ready to make a quit attempt, whereas an individual who is ready to try to stop will benefit from more detailed assessment of their reasons for smoking and perceived barriers to quitting. Structured support from nurses is also effective.15
Behavioural/psychological interventions More intensive psychological interventions may provide support and may help motivated smokers to deal with the consequences of nicotine withdrawal. Such treatments can be delivered one-to-one, or in a group. Both individual counselling and group therapy increase the chances of quitting.16,17 In a systematic review of nine randomised trials comparing individual counselling to brief advice or usual care, the pooled results showed a benefit from counselling. It increased the likelihood of quitting about one and a half times more than the brief intervention.17 In a systematic review of 22 trials, group therapy programmes were more effective than self-help materials, but not consistently better than other interventions involving personal contact.18 There was no difference between group and individual therapy in the two trials that included both. Groups are theoretically more cost-effective, but their usefulness is limited by difficulties in recruiting and retaining participants.19 Most behavioural programmes are multicomponent in nature, aiming to equip smokers with the motivation, skills and support for quitting and avoiding relapse. They may include a variety of cognitive and behavioural techniques such as training in problem-solving and coping skills, relaxation techniques, contracts based on rewards and punishments, social support and cognitive restructuring. Since most studies have included multiple elements, there is little evidence about which components are the most important. The psychological model that has been most studied as a discrete technique is aversion therapy. Aversion pairs smoking with an unpleasant stimulus, with the aim of extinguishing the urge to smoke. Aversion can be produced pharmacologically (for example, with the drug silver acetate) or by methods such as smoking cigarettes at a fixed, rapid rate to produce unpleasant physiological symptoms. Controlled trials of aversion therapy have given conflicting results. Two studies of silver acetate failed to detect an effect, but the confidence intervals did not rule out either significant benefit or significant harm.20 Other forms of aversion therapy have been studied in 24 randomised trials. Systematic review of these trials found no benefit for non-specific aversive stimuli, but suggestive evidence that rapid smoking might help to increase quit rates.21
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Self-help Many forms of self-help materials are available ranging from brief leaflets to complex manuals. They are also available as audiotapes, videotapes and computer programmes. Self-help materials have the theoretical advantage that they can reach many more people than therapistdelivered interventions.22 They may be given as an adjunct to brief advice or without any personal contact. A systematic review of randomised trials found that self-help materials had no additional benefit over brief personal advice. However, in 12 trials with no face-to-face contact, there was a statistically significant effect of self-help materials, increasing quit rates by about 25% compared to no intervention.23 More recent approaches have concentrated on ways of making self-help materials appropriate for the needs of individual smokers. Rather than providing generic materials, individually tailored materials are prepared taking into account such factors as level of addiction, motivation to quit and readiness to change.24 In eight randomised trials comparing personalised materials to standard materials, there was a significant increase of about 40% in those quitting. There was no evidence that materials tailored solely to group characteristics (such as age, gender or race) were better than standard materials. There is increasing evidence that personal contact by telephone can increase the quit rates achieved with self-help materials. Increasingly self-help materials are available on computer or through the internet, though there is as yet little evidence of whether the method of delivery affects the effectiveness of the materials.
Nicotine replacement therapy (NRT) Nicotine dependence is the main factor preventing people who are motivated to stop from doing so. Withdrawal from nicotine causes a number of unpleasant symptoms, including restlessness, difficulty concentrating, irritability, anxiety, craving for nicotine and change in appetite. These symptoms improve when a cigarette is smoked. The aim of NRT is to improve the symptoms by replacing the nicotine from cigarettes. The usual aim is to break the smoking habit and then wean the patient from NRT. However, there is increasing interest in continued use of NRT to reduce the number of cigarettes smoked, a concept of harm reduction borrowed from drug treatments.25 Not all smokers are nicotine dependent, and NRT is unlikely to be helpful when it is absent. Smoking the first cigarette within an hour of waking and being a heavier smoker (more than about 15/day) suggest nicotine dependence and can be used as questions to assess suitability for nicotine replacement. NRT is available as chewing gum, transdermal patch, nasal spray, inhaler, sub-lingual tablet and lozenge. A systematic review of over 90 trials found that NRT helps people to stop smoking, increasing the chances of quit-
T. LANCASTER ET AL.
ting about one and a half to two times.26 The quit rate was higher in both placebo and NRT arms of trials that included intensive support, so the effect of NRT seems to be to increase the rate from whatever baseline is set by other interventions. It is likely, of course, that more people will succeed when NRT is combined with behavioural support, but there is observational evidence that it is effective even in minimal contact settings, such as purchase over the counter from a pharmacist.27 There is little evidence that any NRT product is more effective than another. One study that directly compared four products found no difference in short term abstinence rates or withdrawal symptoms.28 Thus the decision about which to use should be made according to individual characteristics and preferences. The nicotine patch delivers a steady level of nicotine throughout the day, and can be worn unobtrusively. The main side effect is skin irritation, and it is unsuitable for individuals with widespread skin conditions such as psoriasis. Wearing the patch only during waking hours (16 hours/day) is as effective as wearing it for 24 hours/day. Eight weeks of patch therapy is as effective as longer courses and there is no evidence that tapered therapy is better than abrupt withdrawal. Nicotine gum is unsuitable for individuals with dentures, and many find its taste unpleasant. The nicotine inhaler resembles a cigarette and may be useful for individuals who want a substitute for the act of smoking. The nasal spray delivers nicotine more rapidly and may be suitable for satisfying surges of craving. It tends to cause sneezing and irritation in the nose. Some clinicians recommend combinations of nicotine products (for example, providing a background nicotine level with patches, and controlling cravings with faster acting preparations such as gum or spray). There have been too few trials to provide clear evidence about the effectiveness of patch and gum combinations.29,30 In one trial, the combination of nasal spray and patch was better than patch alone.31
Antidepressants Antidepressants are the newest form of commercially available drug treatment for nicotine dependence. Observations that some patients entered in drug trials for depression seemed to find it easier to give up smoking led to formal trials of several types of antidepressant. The slow release form of the atypical antidepressant bupropion (Zyban) is now licensed for smoking cessation in many countries. It is thought to inhibit neuronal uptake of noradrenaline and dopamine. In two published trials there was a significant increase in quitting in patients taking bupropion compared to placebo. Bupropion increased the quit rate about two and a half to three times.32,33 These trials recruited heavier smokers who were also offered behavioural support. In one trial, bupropion alone
HELPING PARENTS TO STOP SMOKING: WHICH INTERVENTIONS ARE EFFECTIVE?
or combined with a nicotine patch was more effective than nicotine patch alone.32 Recent guidelines have concluded that this is insufficient to establish superiority of bupropion over NRT, and rated them as alternative first line agents for smoking cessation.34,35 Bupropion can cause dry mouth and insomnia, but in the trials serious side effects were rare. The manufacturers report a 0.1% risk of seizures using sustained-release bupropion up to 300 mg/day. There is also evidence that other forms of antidepressant may help smoking cessation. In two placebo-controlled trials the tricyclic antidepressant nortriptyline had a similar effect to bupropion, increasing quit rates almost three-fold.36,37 American guidelines rated nortriptyline as a second line agent after bupropion, on the grounds that it produces more side effects.34 One abstract has reported efficacy for fluoxetine, a selective serotonin re-uptake inhibitor, but the results of other studies of this drug have not yet been published.38 These results raise the possibility that antidepressants as a class may be effective, rather than specific drugs. In the trials the drugs were effective whether depression was present or not, so their effect appears to be independent of mood elevation.
Other pharmacological therapies Licensed primarily as an anti-hypertensive, clonidine shares some pharmacological effects with bupropion and tricyclic antidepressants. A systematic review of six clinical trials showed evidence that it has an effect, but its usefulness is limited by sedation and postural hypotension.39 The American guidelines therefore rate it as a second line agent for smoking cessation.34 The nicotine antagonist mecamylamine has been investigated as a cessation aid in combination with nicotine replacement, but is not licensed for this use. The evidence from two studies suggests an effect of mecamylamine, started precessation and continued post-cessation, in aiding smoking cessation.40 The studies also suggest that the combination of mecamylamine with nicotine replacement, started before cessation, may increase the rates of cessation beyond those achieved with nicotine alone. Anxiolytic medications have been studied in a number of trials, but a systematic review failed to find evidence that they are effective.41
Complementary therapies A systematic review of twenty trials found no benefit of acupuncture compared to sham acupuncture. Acupuncture may be better than doing nothing, but this is likely to be a placebo effect.42 A systematic review of nine small trials of hypnotherapy found it no more effective than other behavioural interventions.43
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PREGNANCY Encouraging pregnant mothers to stop smoking is particularly important for the future health of their children. Although there is no clear evidence of harm to the foetus from NRT or antidepressants, most strategies for helping pregnant women to stop focus on counselling and behavioural support.44
CONCLUSIONS Giving up smoking is a difficult task that usually requires a number of attempts. Social and economic factors interact with personal susceptibility in determining whether individuals are successful in quitting smoking. Attributing success to discrete clinical interventions is therefore difficult.45 Clinical interventions are not the whole solution, but they are part of it, and there is increasing evidence for the effectiveness of a number of interventions. There is no clear rank order for these interventions. At a minimum, health professionals should find out about the smoking status of patients (or the parents of paediatric patients) and offer them brief advice about stopping smoking. Motivated individuals may benefit from further behavioural support. In smokers with evidence of nicotine dependence, this may be combined with the offer of nicotine replacement therapy or antidepressants to reduce withdrawal symptoms and increase the chances of a successful quit attempt.
PRACTICE POINTS • Exposure of children to passive smoking increases the risk of respiratory tract infections, otitis media, asthma and the sudden infant death syndrome. • Stopping smoking is more effective than restricting parental smoking in reducing children’s exposure. • Simple advice from doctors can help motivate a quit attempt. • Quit attempts are more likely to succeed with support and treatment for nicotine dependence. • Effective treatments for nicotine dependence include behavioural counselling, nicotine replacement therapy and antidepressants.
REFERENCES 1. Cook DG, Strachan DP. Health effects of passive smoking-10: Summary of effects of parental smoking on the respiratory health of children and implications for research. Thorax 1999; 54: 357–366. 2. Hovell MF, Zakarian JM, Matt GE, Hofstetter CR, Bernert JT, Pirkle J. Effect of counselling mothers on their children’s exposure to environmental tobacco smoke: randomised controlled trial. BMJ 2000; 321: 337–342.
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3. Wakefield MA, Chaloupka FJ, Kaufman NJ, Orleans CT, Barker DC, Ruel EE. Effect of restrictions on smoking at home, at school, and in public places on teenage smoking: cross sectional study. BMJ 2000; 321: 333–337. 4. Jarvis MJ, Goddard E, Higgins V, Feyerabend C, Bryant A, Cook DG. Children’s exposure to passive smoking in England since the 1980s: cotinine evidence from population surveys. BMJ 2000; 321: 343–345. 5. Farkas AJ, Gilpin EA, White MM, Pierce JP. Association between household and workplace smoking restrictions and adolescent smoking. JAMA 2000; 284: 717–722. 6. Hughes JR. Four beliefs that may impede progress in the treatment of smoking. Tob. Control 1999; 8: 323–326. 7. Lancaster T, Stead L, Silagy C, Sowden A. Effectiveness of interventions to help people stop smoking: findings from the Cochrane Library. BMJ 2000; 321: 355–358. 8. Jarvis MJ, Wardle J. Social patterning of individual behaviours: the case of cigarette smoking. In: Marmot MG, Wilkinson RG, eds. Social Determinants of Health. Oxford: Oxford University Press, 1999; 240–256. 9. Liu BQ, Peto R, Chen ZM, et al. Emerging tobacco hazards in China: 1. Retrospective proportional mortality study of one million deaths. BMJ 1998; 317: 1411–1422. 10. Niu SR, Yang GH, Chen ZM, et al. Emerging tobacco hazards in China: 2. Early mortality results from a prospective study. BMJ 1998; 317: 1423–1424. 11. Peto R, Lopez AD. The future of worldwide smoking patterns. In: C Everett Koop, Clarence E Pearson, M Roy Schwarz, eds. Critical Issues in Global Health. New York: Jossey-Bass, 2000; 154–161. 12. Silagy C. Physician advice for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 13. Hughes JR, Goldstein MG, Hurt RD, Shiffman S. Recent advances in the pharmacotherapy of smoking. JAMA 1999; 281: 72–76. 14. Prochaska JO, Velicer WF. The transtheoretical model of health behavior change. Am. J. Health Promot. 1997; 12: 38–48. 15. Rice VH, Stead LF. Nursing interventions for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 16. Stead LF, Lancaster T. Group behaviour therapy programmes for smoking cessation(Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 17. Lancaster T, Stead LF. Individual behavioural counselling for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 18. Stead LF, Lancaster, T. Group behaviour therapy programmes for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 19. Hollis JF, Lichtenstein E, Vogt TM, Stevens VJ, Biglan A. Nurse-assisted counseling for smokers in primary care. Ann Intern Med 1993; 118: 521–525. 20. Lancaster T, Stead LF. Silver acetate for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 21. Hajek P, Stead LF. Aversive smoking for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 22. Curry SJ. Self-help interventions for smoking cessation. J Consult Clin Psychol 1993; 61: 790–803. 23. Lancaster T, Stead LF. Self-help interventions for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 24. Prochaska JO, Velicer WF. The transtheoretical model of health behavior change. Am J Health Promot 1997; 12: 38–48.
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25. Hughes JR. The future of smoking cessation therapy in the United States. Addiction 1996; 91: 1797–1802. 26. Silagy C, Mant D, Fowler G, Lancaster T. Nicotine replacement therapy for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 27. Shiffman S, Gitchell J, Pinney JM, Burton SL, Kemper KE, Lara EA. Public health benefit of over-the-counter nicotine medications. Tob Control 1997; 6: 306–310. 28. Hajek P, West R, Foulds J, Nilsson F, Burrows S, Meadow A. Randomized comparative trial of nicotine polacrilex, a transdermal patch, nasal spray, and an inhaler. Arch Intern Med 1999; 159: 2033–2038. 29. Puska P, Korhonen HJ, Vartiainen E, Urjanheimo EL, Gustavsson G, Westin A. Combined use of nicotine patch and gum compared with gum alone in smoking cessation: a clinical trial in North Karelia. Tob Control 1995; 4: 231–235. 30. Kornitzer M, Boutsen M, Dramaix M, Thijs J, Gustavsson G. Combined use of nicotine patch and gum in smoking cessation: a placebo-controlled clinical-trial. Prev Med 1995; 24: 41–47. 31. Blondal T, Gudmundsson LJ, Olafsdottir I, Gustavsson G, Westin A. Nicotine nasal spray with nicotine patch for smoking cessation: randomised trial with six year follow up. BMJ 1999; 318: 285–288. 32. Jorenby DE, Leischow SJ, Nides MA, Rennard SI, Johnston JA, Hughes AR et al. A controlled trial of sustained-release bupropion, a nicotine patch, or both for smoking cessation. N Engl J Med 1999; 340: 685–691. 33. Hurt RD, Sachs DP, Glover ED, Offord KP, Johnston JA, Dale LC et al. A comparison of sustained-release bupropion and placebo for smoking cessation. N Engl J Med 1997; 337: 1195–1202. 34. A clinical practice guideline for treating tobacco use and dependence: A US Public Health Service report. The Tobacco Use and Dependence Clinical Practice Guideline Panel, Staff, and Consortium Representatives. JAMA 2000; 283: 3244–3254. 35. West R, McNeill A, Raw M. Smoking cessation guidelines for health professionals: an update. Thorax 2000; 55: 987–999. 36. Prochazka AV, Weaver MJ, Keller RT, Fryer GE, Licari PA, Lofaso D. A randomized trial of nortriptyline for smoking cessation. Arch Intern Med 1998; 158: 2035–2039. 37. Hall SM, Reus VI, Munoz RF, et al. Nortriptyline and cognitivebehavioral therapy in the treatment of cigarette smoking. Arch Gen Psychiatry 1998; 55: 683–690. 38. Niaura R, Spring B, Keuthen NJ, et al. Fluoxetine for smoking cessation: A multicenter randomized double blind dose response study [abstract]. Ann Behav Med 1997; 19: S042. 39. Gourlay SG, Stead LF, Benowitz NL. Clonidine for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 40. Lancaster T, Stead LF. Mecamylamine (a nicotine antagonist) for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 41. Hughes, JR, Stead, LF, Lancaster, T. Anxiolytics for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 42. White AR, Rampes H, Ernst E. Acupuncture for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 43. Abbot, NC, Stead, LF, White, AR, Barnes, J, Ernst, E. Hypnotherapy for smoking cessation (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 44. Lumley J, Oliver S, Waters E. Interventions for promoting smoking cessation during pregnancy (Cochrane Review). In: The Cochrane Library, Issue 1, 2001. Oxford: Update Software. 45. Chapman S. Unravelling gossamer with boxing gloves: problems in explaining the decline in smoking. BMJ 1993; 307: 429–432.
MINI-SYMPOSIUM: SMOKING: EFFECTS ON THE PAEDIATRIC LUNG
Helping parents to stop smoking: which interventions are effective? T. Lancaster, L. Stead and S. Shepperd Department of Primary Health Care, University of Oxford Institute of Health Sciences, Old Road, Headington, Oxford OX3 7LF KEYWORDS smoking cessation, tobacco smoke pollution, nicotine replacement therapy, bupropion (Zyban).
Summary Parental smoking increases children’s risk of respiratory illness. Encouraging parents not to smoke in the home helps, but stopping smoking altogether is more effective in reducing children’s exposure. The prevalence of smoking increases with higher levels of social disadvantage and is therefore a major contributor to widening inequalities in health. Randomised trials have shown that adults can be helped to stop with simple advice from health professionals, behavioural support, nicotine replacement and antidepressants. ° C 2001 Harcourt Publishers Ltd
INTRODUCTION Exposure of children to passive smoking increases the risk of respiratory tract infections, otitis media, asthma and the sudden infant death syndrome.1 Parental smoking is the most important source of this exposure. One strategy for reducing children’s exposure to smoking is to ban smoking in the home. Programmes aimed at persuading parents not to smoke in the home can reduce exposure,2 and may lead to fewer children taking up smoking.3 However, analysis of cotinine levels at a population level has shown that smoking cessation by parents is a more effective way of reducing children’s exposure. In a study of non-smoking secondary schoolchildren in the United Kingdom, almost all the decrease in cotinine concentrations was accounted for by parents giving up, rather than restricting, smoking.4 Children of parents who give up smoking are also less likely to initiate the habit themselves.5 Hence, helping adult smokers to stop is important for their future as well as their current health, reducing the risk that they will die prematurely of cancer, respiratory or cardiovascular disease. Although some smokers quit without formal help, an increasing number succeed only after receiving some Correspondence to: Dr Lancaster, Clinical Reader and coordinating editor, Cochrane Tobacco Addiction Review Group. E-mail: [email protected] 1526–0550/01/030222 + 05 $35.00/0
form of support or treatment.6 There are a growing number of interventions advocated to help people to quit smoking, including behavioural, pharmacological and complementary therapies. The purpose of this review is to provide information to health professionals caring for children about the effectiveness of interventions to help smoking parents to stop.
METHODS The Cochrane Tobacco Addiction Review Group aims to identify and review data from randomised trials about interventions for preventing and reducing smoking. This review draws on the database of studies on smoking maintained by the group. Our conclusions about the effectiveness of interventions are based, wherever possible, on the findings of randomised trials and systematic reviews of randomised trials.7
WHY DO PEOPLE SMOKE AND WHY DO THEY STOP? Smoking is sustained by a complex interaction of social, psychological and biological factors, which find a common pathway in addiction to nicotine. Social factors appear to be of increasing importance. In the United Kingdom, the overall prevalence of smoking has fallen substantially in ° C 2001 Harcourt Publishers Ltd
HELPING PARENTS TO STOP SMOKING: WHICH INTERVENTIONS ARE EFFECTIVE?
the past 20 years (between 1973 and 1996 it fell from 53% to 29% in men and from 42% to 28% in women).8 However, these encouraging data hide a widening disparity between different social classes. While rates among the most affluent have fallen by more than 50% in Britain over 20 years, they have not decreased at all among the most deprived. In the United Kingdom, the likelihood that an individual will smoke is greater in lower occupational class groups, of lower educational attainment, those living in rented housing, without access to a car, who are unemployed and in overcrowded accommodation. The risk of smoking is also increased in those who are divorced, separated or lone parents. It is particularly high in people who are homeless, heavy users of alcohol or mentally ill.8 Among the most disadvantaged sectors of British society over 80% of adults smoke. These disparities contribute in turn to widening inequalities in health status between the social classes. The pattern is similar in other countries in which the tobacco epidemic is mature. Meanwhile, in many less affluent countries, historically low rates of smoking are increasing, fuelled by advertising that associates smoking with perceptions of increasing prosperity.9,10 Peto and Lopez11 have estimated that current patterns of cigarette smoking will cause about 450 million premature deaths world-wide in the next 50 years. Many of these deaths will occur in societies where life expectancy is already reduced by other poverty related diseases of nutrition and infection. If smoking is mainly a social issue, then a large part of the solution lies in improving the environment of those who smoke, by providing higher incomes, better housing and improved education. However, this long-term strategy needs to be supplemented by shorter-term solutions. Smokers who give up before middle age shed almost all the excess risk of mortality associated with smoking (and produce immediate benefits for their children). Peto and Lopez have estimated that a reduction of 50% in current smoking would avoid between a third and a half of the premature deaths forecast for the first half of the current century.11 These health benefits can only be achieved by helping current smokers to give up.
INTERVENTIONS Advice from health professionals The simplest way for health workers to help people to give up smoking is to offer them advice. Simple advice from doctors during routine clinical care has been studied in 31 randomised trials including over 26 000 smokers. A systematic review of these trials showed that advice consistently increases the number of people who stop, by about one and a half to two times.12 The effect of advice is probably to motivate a quit attempt, rather than to increase the chances of a quit attempt succeeding.13 Therefore, advice will usually be more effective when it
223
is linked to further support and treatment for nicotine dependence. Little is known about the ideal content of the advice. However, there is both theoretical and practical validity to an approach based on an assessment of the patient’s motivation to stop.14 A simple message of advice will be appropriate for someone who is not ready to make a quit attempt, whereas an individual who is ready to try to stop will benefit from more detailed assessment of their reasons for smoking and perceived barriers to quitting. Structured support from nurses is also effective.15
Behavioural/psychological interventions More intensive psychological interventions may provide support and may help motivated smokers to deal with the consequences of nicotine withdrawal. Such treatments can be delivered one-to-one, or in a group. Both individual counselling and group therapy increase the chances of quitting.16,17 In a systematic review of nine randomised trials comparing individual counselling to brief advice or usual care, the pooled results showed a benefit from counselling. It increased the likelihood of quitting about one and a half times more than the brief intervention.17 In a systematic review of 22 trials, group therapy programmes were more effective than self-help materials, but not consistently better than other interventions involving personal contact.18 There was no difference between group and individual therapy in the two trials that included both. Groups are theoretically more cost-effective, but their usefulness is limited by difficulties in recruiting and retaining participants.19 Most behavioural programmes are multicomponent in nature, aiming to equip smokers with the motivation, skills and support for quitting and avoiding relapse. They may include a variety of cognitive and behavioural techniques such as training in problem-solving and coping skills, relaxation techniques, contracts based on rewards and punishments, social support and cognitive restructuring. Since most studies have included multiple elements, there is little evidence about which components are the most important. The psychological model that has been most studied as a discrete technique is aversion therapy. Aversion pairs smoking with an unpleasant stimulus, with the aim of extinguishing the urge to smoke. Aversion can be produced pharmacologically (for example, with the drug silver acetate) or by methods such as smoking cigarettes at a fixed, rapid rate to produce unpleasant physiological symptoms. Controlled trials of aversion therapy have given conflicting results. Two studies of silver acetate failed to detect an effect, but the confidence intervals did not rule out either significant benefit or significant harm.20 Other forms of aversion therapy have been studied in 24 randomised trials. Systematic review of these trials found no benefit for non-specific aversive stimuli, but suggestive evidence that rapid smoking might help to increase quit rates.21
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Self-help Many forms of self-help materials are available ranging from brief leaflets to complex manuals. They are also available as audiotapes, videotapes and computer programmes. Self-help materials have the theoretical advantage that they can reach many more people than therapistdelivered interventions.22 They may be given as an adjunct to brief advice or without any personal contact. A systematic review of randomised trials found that self-help materials had no additional benefit over brief personal advice. However, in 12 trials with no face-to-face contact, there was a statistically significant effect of self-help materials, increasing quit rates by about 25% compared to no intervention.23 More recent approaches have concentrated on ways of making self-help materials appropriate for the needs of individual smokers. Rather than providing generic materials, individually tailored materials are prepared taking into account such factors as level of addiction, motivation to quit and readiness to change.24 In eight randomised trials comparing personalised materials to standard materials, there was a significant increase of about 40% in those quitting. There was no evidence that materials tailored solely to group characteristics (such as age, gender or race) were better than standard materials. There is increasing evidence that personal contact by telephone can increase the quit rates achieved with self-help materials. Increasingly self-help materials are available on computer or through the internet, though there is as yet little evidence of whether the method of delivery affects the effectiveness of the materials.
Nicotine replacement therapy (NRT) Nicotine dependence is the main factor preventing people who are motivated to stop from doing so. Withdrawal from nicotine causes a number of unpleasant symptoms, including restlessness, difficulty concentrating, irritability, anxiety, craving for nicotine and change in appetite. These symptoms improve when a cigarette is smoked. The aim of NRT is to improve the symptoms by replacing the nicotine from cigarettes. The usual aim is to break the smoking habit and then wean the patient from NRT. However, there is increasing interest in continued use of NRT to reduce the number of cigarettes smoked, a concept of harm reduction borrowed from drug treatments.25 Not all smokers are nicotine dependent, and NRT is unlikely to be helpful when it is absent. Smoking the first cigarette within an hour of waking and being a heavier smoker (more than about 15/day) suggest nicotine dependence and can be used as questions to assess suitability for nicotine replacement. NRT is available as chewing gum, transdermal patch, nasal spray, inhaler, sub-lingual tablet and lozenge. A systematic review of over 90 trials found that NRT helps people to stop smoking, increasing the chances of quit-
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ting about one and a half to two times.26 The quit rate was higher in both placebo and NRT arms of trials that included intensive support, so the effect of NRT seems to be to increase the rate from whatever baseline is set by other interventions. It is likely, of course, that more people will succeed when NRT is combined with behavioural support, but there is observational evidence that it is effective even in minimal contact settings, such as purchase over the counter from a pharmacist.27 There is little evidence that any NRT product is more effective than another. One study that directly compared four products found no difference in short term abstinence rates or withdrawal symptoms.28 Thus the decision about which to use should be made according to individual characteristics and preferences. The nicotine patch delivers a steady level of nicotine throughout the day, and can be worn unobtrusively. The main side effect is skin irritation, and it is unsuitable for individuals with widespread skin conditions such as psoriasis. Wearing the patch only during waking hours (16 hours/day) is as effective as wearing it for 24 hours/day. Eight weeks of patch therapy is as effective as longer courses and there is no evidence that tapered therapy is better than abrupt withdrawal. Nicotine gum is unsuitable for individuals with dentures, and many find its taste unpleasant. The nicotine inhaler resembles a cigarette and may be useful for individuals who want a substitute for the act of smoking. The nasal spray delivers nicotine more rapidly and may be suitable for satisfying surges of craving. It tends to cause sneezing and irritation in the nose. Some clinicians recommend combinations of nicotine products (for example, providing a background nicotine level with patches, and controlling cravings with faster acting preparations such as gum or spray). There have been too few trials to provide clear evidence about the effectiveness of patch and gum combinations.29,30 In one trial, the combination of nasal spray and patch was better than patch alone.31
Antidepressants Antidepressants are the newest form of commercially available drug treatment for nicotine dependence. Observations that some patients entered in drug trials for depression seemed to find it easier to give up smoking led to formal trials of several types of antidepressant. The slow release form of the atypical antidepressant bupropion (Zyban) is now licensed for smoking cessation in many countries. It is thought to inhibit neuronal uptake of noradrenaline and dopamine. In two published trials there was a significant increase in quitting in patients taking bupropion compared to placebo. Bupropion increased the quit rate about two and a half to three times.32,33 These trials recruited heavier smokers who were also offered behavioural support. In one trial, bupropion alone
HELPING PARENTS TO STOP SMOKING: WHICH INTERVENTIONS ARE EFFECTIVE?
or combined with a nicotine patch was more effective than nicotine patch alone.32 Recent guidelines have concluded that this is insufficient to establish superiority of bupropion over NRT, and rated them as alternative first line agents for smoking cessation.34,35 Bupropion can cause dry mouth and insomnia, but in the trials serious side effects were rare. The manufacturers report a 0.1% risk of seizures using sustained-release bupropion up to 300 mg/day. There is also evidence that other forms of antidepressant may help smoking cessation. In two placebo-controlled trials the tricyclic antidepressant nortriptyline had a similar effect to bupropion, increasing quit rates almost three-fold.36,37 American guidelines rated nortriptyline as a second line agent after bupropion, on the grounds that it produces more side effects.34 One abstract has reported efficacy for fluoxetine, a selective serotonin re-uptake inhibitor, but the results of other studies of this drug have not yet been published.38 These results raise the possibility that antidepressants as a class may be effective, rather than specific drugs. In the trials the drugs were effective whether depression was present or not, so their effect appears to be independent of mood elevation.
Other pharmacological therapies Licensed primarily as an anti-hypertensive, clonidine shares some pharmacological effects with bupropion and tricyclic antidepressants. A systematic review of six clinical trials showed evidence that it has an effect, but its usefulness is limited by sedation and postural hypotension.39 The American guidelines therefore rate it as a second line agent for smoking cessation.34 The nicotine antagonist mecamylamine has been investigated as a cessation aid in combination with nicotine replacement, but is not licensed for this use. The evidence from two studies suggests an effect of mecamylamine, started precessation and continued post-cessation, in aiding smoking cessation.40 The studies also suggest that the combination of mecamylamine with nicotine replacement, started before cessation, may increase the rates of cessation beyond those achieved with nicotine alone. Anxiolytic medications have been studied in a number of trials, but a systematic review failed to find evidence that they are effective.41
Complementary therapies A systematic review of twenty trials found no benefit of acupuncture compared to sham acupuncture. Acupuncture may be better than doing nothing, but this is likely to be a placebo effect.42 A systematic review of nine small trials of hypnotherapy found it no more effective than other behavioural interventions.43
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PREGNANCY Encouraging pregnant mothers to stop smoking is particularly important for the future health of their children. Although there is no clear evidence of harm to the foetus from NRT or antidepressants, most strategies for helping pregnant women to stop focus on counselling and behavioural support.44
CONCLUSIONS Giving up smoking is a difficult task that usually requires a number of attempts. Social and economic factors interact with personal susceptibility in determining whether individuals are successful in quitting smoking. Attributing success to discrete clinical interventions is therefore difficult.45 Clinical interventions are not the whole solution, but they are part of it, and there is increasing evidence for the effectiveness of a number of interventions. There is no clear rank order for these interventions. At a minimum, health professionals should find out about the smoking status of patients (or the parents of paediatric patients) and offer them brief advice about stopping smoking. Motivated individuals may benefit from further behavioural support. In smokers with evidence of nicotine dependence, this may be combined with the offer of nicotine replacement therapy or antidepressants to reduce withdrawal symptoms and increase the chances of a successful quit attempt.
PRACTICE POINTS • Exposure of children to passive smoking increases the risk of respiratory tract infections, otitis media, asthma and the sudden infant death syndrome. • Stopping smoking is more effective than restricting parental smoking in reducing children’s exposure. • Simple advice from doctors can help motivate a quit attempt. • Quit attempts are more likely to succeed with support and treatment for nicotine dependence. • Effective treatments for nicotine dependence include behavioural counselling, nicotine replacement therapy and antidepressants.
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