Clinical Review ABC of smoking cessation

Harm reduction

BMJ 2004; 328 doi: https://doi.org/10.1136/bmj.328.7444.885 (Published 08 April 2004) Cite this as: BMJ 2004;328:885
  1. Ann McNeill, independent consultant in public health and an honorary senior lecturer in the psychology department
  1. St George's Hospital Medical School, London

    Introduction

    Although the ideal for all smokers is to quit completely, a substantial proportion of smokers either do not want to stop smoking or have been unable to do so despite many attempts. Harm reduction strategies are aimed at reducing the adverse health effects of tobacco use in these individuals.

    Cutting down

    Cutting down on the number of cigarettes smoked each day is a common strategy used by smokers to reduce harm, to move towards quitting, or to save money. Some health professionals also advocatecutting down if smokers cannot or will not stop. No evidence exists, however, that major health risks are reduced by this strategy. The likely explanation for this is that smoking is primarily a nicotine seeking behaviour, and smokers who cut down tend to compensate by taking more and deeper puffs from each cigarette, and smoking more of it. This results in a much smaller proportional reduction in intake of nicotine (and in associated tar and other toxins) than the reduction in number of cigarettes smoked suggests.

    Figure1

    Prospective hazard ratios for death for smokers who cut down or quit compared with continuing heavy smokers. Adapted from Godtfredsen et al (Am J Epidemiol 2002;156: 994-1001

    Cutting down on cigarettes in conjunction with the use of nicotine replacement therapy (NRT) tomaintain nicotine levels is a more promising strategy, although NRT is not currently licensed in the United Kingdom or in many other countries for use in this way. Preliminary studies have suggested that this approach may help with sustained cigarette reduction and reduce intake of toxins, butno strong evidence exists yet of health benefit from this strategy.

    Switching to “low tar” cigarettes

    Many smokers who are concerned about the health effects of smoking switch to “low tar” cigarettes, in the belief that these are less dangerous than ordinary cigarettes. This perception has been encouraged by the tobacco industry and, in many countries, also by government policies seeking aprogressive reduction in the tar yields of cigarettes.

    Equating low tar with “healthy”: market research for Silk Cut (manufactured by Gallaher)

    View this table:

    Embedded Image

    “Low tar” cigarettes showing ventilation holes in the filters

    However, tar yields from cigarettes are measured by machines that artificially “smoke” the cigarettes, and much of the reduction in the tar yield of low tar cigarettes, as measured by a smokingmachine, results from ventilation holes introduced in the filter to dilute the smoke drawn in by the machine. The ratio of tar to nicotine produced in the tobacco smoke of low tar cigarettes is infact closely similar to that of conventional cigarettes. Low tar therefore also means low nicotine.

    Figure2

    Tar and nicotine yields for 187 cigarette brands tested by the UK Laboratory of the Government Chemist (data from www.open.gov.uk/doh/dhhome.htm)

    Enabling smokers to take control of their cigarette consumption—by using NRT at the same time as cutting down on smoking—may also increase smokers' confidence and ability to quit subsequently

    As with cutting down, smokers who switch to lower yield brands tend to compensate for the reduction in nicotine delivery by changing their smoking pattern. With low tar cigarettes smokers do this in two main ways—they smoke the cigarettes more “strongly” by taking more or deeper puffs or they occlude the filter ventilation holes with fingers or lips to prevent or reduce smoke dilution. This results in very little, if any, change in actual intake of nicotine—and consequently of tar—and ultimately therefore, in little reduction in harm.

    Figure3

    Effect of compensation by smokers when smoking low tar cigarettes, as shown by mean blood levels of cotinine (with 95% confidence intervals) and related nicotine yield over time. 1=run-in to study; 2=entry; 3=at 2 months; 4=at 4 months; 5=at 6 months. Adapted from Frost et al (Thorax 1995;50: 1038-43

    Switching to cigars or pipes

    Some cigarette smokers, particularly men, switch to smoking cigars or pipes as a means of giving up cigarettes. The risks of smoking cigars or pipes for smokers who have never been regular cigarette smokers are indeed much lower than in former cigarette smokers, principally because they tend not to inhale the smoke but rely on nicotine absorption from the buccal mucosa. Cigarette smokers who switch to cigars or pipes tend, however, to continue to inhale the smoke and are therefore likely to gain little or no health benefit.

    Alternative cigarettes

    Several tobacco companies have designed and in some cases marketed alternative smoking productsthat heat rather than burn tobacco or tobacco products. An example is the Eclipse brand of cigarettes, now marketed in the United States with the claim of being a safer alternative to conventionalcigarettes. Eclipse delivers less tar than conventional cigarettes, but more carbon monoxide, soany harm reduction is likely to be limited. No studies have yet shown health benefits associated with switching to Eclipse or similar alternative smoking products.

    Figure4

    According to the manufacturer, R J Reynolds (RJR), Eclipse cigarettes are “designed to burn only about 3% as much tobacco as other cigarettes.” RJR also explains that they “create smoke primarily by heating tobacco rather than burning it” www.eclipse.rjrt.com

    Switching to smokeless tobacco

    Smokeless tobacco comes in two main forms—snuff and chewing tobacco. The types of smokeless tobacco product used around the world vary considerably, as do the health risks across the products used. For example, in India, use of smokeless tobacco is a major cause of oral cancer. Neverthelessthe health risks associated with smokeless tobacco are considerably smaller than those associated with cigarettes.

    In Sweden the use of oral moist snuff (known as snus) has been common among men for several decades. The health risks of this product seem to be extremely low, in absolute terms as well as in relation to cigarette smoking. Snus seems to be widely used by smokers as an alternative to cigarettes, contributing to the low overall prevalence of smoking and smoking related disease in Sweden.

    Snus and other smokeless oral tobacco products currently being developed by some tobacco companies could therefore provide a viable alternative to smoking for many smokers in other countries, and thus deliver substantial health gains. However, these products are currently prohibited throughout the European Union (except in Sweden) on the grounds that they are unsafe.


    Embedded Image

    Swedish snus, with pound coins for scale

    Some experts have argued that even if smokeless tobacco is a less harmful form of nicotine intake than smoking, its availability might have unintended undesirable consequences, such as causing harm to people who might have otherwise quit smoking completely. Other health experts have recommended that smokers should have the right to be able to choose less harmful forms of nicotine delivery, such as snus. They argue that the ban on the less harmful smokeless tobacco products should belifted—within an evidence based regulatory framework that favours the least harmful forms of smokeless tobacco—and that smokers should be encouraged to use them.

    Some experts say that smokeless tobacco may attract more young people to tobacco use and subsequently smoking

    Switching to pharmaceutical nicotine products

    Switching from cigarettes to pharmaceutical nicotine products—that is, NRT—is standard practicein managing smoking cessation, but these products are not currently licensed for long term use as an alternative to smoking. Given that the risks associated with NRT are much lower than those associated with smoking, long term use of NRT products is a rational harm reduction strategy.

    Key points

    View this table:

    However, as most smokers do not find the current NRT products to be as satisfying as cigarettes,the viability of these products as a long term substitute is limited. The technology to develop safe, inhaled forms of nicotine that could provide a more satisfactory alternative to cigarette smoking is available in the pharmaceutical industry, but in the context of the current regulatory framework in the United Kingdom and many other countries, such products would not be licensed and aretherefore not commercially viable. As discussed above and in the previous article in this series, this imbalance in the regulation of nicotine needs to be redressed urgently in favour of public health.

    Further reading

    • Tobacco Advisory Group of the Royal College of Physicians. Regulation of nicotine intake by smokers, and implications for health. In: Nicotine addiction in Britain. London:RCP, 2000. (A report of the Tobacco Advisory Group of the Royal College of Physicians, Chapter 6.)

    • Stratton K, Shetty P, Wallace R, Bondurant S, eds.Clearing the smoke: assessing the science base for tobacco harm reduction. Washington, DC: National Academy Press, 2001.

    • Ferrence R, Slade J, Room R, Pope M, eds.Nicotine and public health.Washington, DC: American Public Health Association, 2000.

    • Tobacco Advisory Group of the Royal College of Physicians. Protecting smokers, saving lives. The case for a tobacco and nicotine regulation authority. London: RCP, 2002.

    • National Cancer Institute. Risks associated with smoking cigarettes and low machine-measured yields of tar and nicotine. Bethesda, MD: US Department of Health and Human Services, National Institutes of Health, National Cancer Institute, 2001. (Smoking and tobaccocontrol monograph No 13; NIH publication No 02-5074.)

    Acknowledgments

    The ABC of smoking cessation is edited by John Britton, professor of epidemiology at the University of Nottingham in the division of epidemiology and public health at City Hospital, Nottingham. The series will be published as a book in the late spring.

    Footnotes

    • Competing interests Ann McNeill has received two honorariums and hospitality from manufacturers of tobacco dependence treatments. See first article in this series (24 January 2004) for the series editor's competing interests

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