Smoking reduction

© 2010 NHS Centre for Smoking Cessation and Training (NCSCT)
Author: Lion Shahab
Editor: Andy McEwen

Executive summary

Smoking reduction, cutting down the cigarettes smoked per day, is common in the UK. However, the amount that smokers cut down by is relatively small and there is little evidence to suggest that reducing cigarette consumption in itself has a positive effect on smoking-related outcomes. This is most likely due to the fact that smokers who cut down compensate for this reduction by increasing the intensity with which they smoke cigarettes to maintain a relatively stable level of nicotine intake. Consequently, data suggest that smoking reduction does not significantly reduce smoking-related mortality or morbidity. Whilst unaided smoking reduction has not been reliably shown to increase quit attempts or smoking cessation rates, there is good evidence that the provision of NRT to smokers who cut down their cigarette consumption results in longer, substantial decreases in cigarette consumption and improves their chances to stop smoking completely. For this reason, NRT in the UK is now licensed for smoking reduction and available to smokers who cannot or are unwilling to stop smoking completely as a harm reduction measure.

Key points

1. Smoking reduction in the population

1.1 Prevalence

  • Smoking reduction, cutting down the cigarettes smoked per day, is a common strategy for smokers to mitigate the financial and health effects of smoking and to move towards smoking cessation.1 It is particularly appealing for smokers who cannot or will not stop.2
  • Evidence from the UK suggests that over 50% of the smoking population currently report that they are attempting to reduce their cigarette consumption.3

1.2 Compensatory smoking

  • Whilst smokers attempting to cut down report on average to smoke two cigarettes fewer per day than those not trying to cut down3, evidence suggests that there is not a linear relationship between cigarette consumption and exposure to cigarette smoke constituents such as nicotine or tobacco-specific carcinogens.4,5
  • This is most likely due to 'compensatory smoking'. Most smokers use cigarettes to obtain a relatively constant amount of nicotine over the day.6 However, besides the number of cigarettes smoked, there exist a number of other factors that impact the daily delivery of nicotine including the number, size, speed and intensity of puffs taken as well as the blocking of filter vents.7 Thus when smokers reduce their cigarette consumption, they may compensate by adjusting the way they smoke cigarettes to maintain a desired level of nicotine.8 Indeed, switching studies have shown that when smokers are randomised to 'low tar' cigarettes yielding less nicotine, they compensate to extract the same amount of nicotine from these cigarettes (Figure 1).9

Figure 1. Effect of compensation by smokers when smoking low tar cigarettes, as shown by blood levels of cotinine, with 95% confidence intervals, and related nicotine yield over time. Adapted from Frost et al, 1995. 9 (Click on image to enlarge) 


1 = run-in to study; 2 = entry; 3 = at 2 months; 4 = at 4 months; 5 = at 6 months.

  • The consequence of 'compensatory smoking' may therefore be that smoking reduction does not result in a reduction of the harmful consequences of smoking because smokers will simply smoke each cigarette more intensely, receiving the same level of toxins as smokers not reducing their consumption. Short-term studies confirm that reducing cigarette consumption only leads to a relatively modest reduction in exposure to biomarkers of smoking-related harm. 10–12

2. Effects of unaided smoking reduction

2.1 Effects on quit attempts and smoking cessation

  • Retrospective studies suggest that smokers attempting to reduce their consumption are more likely to have made previous quit attempts3; however, smoking reduction may be an after-effect of a failed quit attempt.13,14 Longitudinal data suggest that unassisted smoking reduction may be associated with a greater likelihood of attempts to stop smoking in the short but not long-term.15
  • Whilst data are mixed on the impact on quit attempts, smoking reduction may also increase the chances of success of quit attempts and thus increase cessation rates. There is some evidence that smoking reduction predicts greater abstinence rates in some16–18 but not other studies.19–21 Thus, current evidence is at best ambiguous as to whether unaided smoking reduction is effective for increasing quit attempts or smoking cessation.
  • The interpretation of findings is further complicated by two factors: (1) Studies rely on self-selected samples and it may be that smokers who chose to reduce consumption are simply more motivated to stop than those who chose not to; (2) Where effects are found, smoking reduction is usually defined as reducing the amount smoked by ≥ 50%, whereas in the general population smoking reduction is usually only between 1–5%, not maintained long-term and less than 10% of smokers who cut down, reduce their consumption by more than 50%.14

2.2 Effects on health outcomes

  • Given that there is no clear evidence that unaided smoking reduction increases abstinencerates, there is yet the possibility that smoking reduction per se decreases harm from smoking. The best evidence comes from large longitudinal studies such as reported in Figure 2, which suggest that there is no health benefit of smoking reduction on major smoking-related diseases.22

Figure 2. Data from large 16 year-long Danish cohort study showing hazard ratio of deaths from various causes adjusted for relevant confounders (95% confidence interval). Adapted from Godtfredsen et al, 2002. 22 (Click on the image to enlarge)

  • There is also little evidence that smoking reduction improves lung function,23 though there may be some marginal benefit if smoking reduction is sustained and substantial,24 or that it substantially decreases lung cancer risk, myocardial infarction or COPD.15,25
  • Lastly, studies have not found a positive effect of smoking reduction on post-operative complications or, among pregnant smokers, on infant birth weight.15,25 Taken together, these results suggest that the reduction in cigarette consumption is likely to be largely counterbalanced by compensatory mechanism such as adjustment in smoking intensity leading to no or only very small changes in exposure to tobacco smoke and thus smoking-related health risks.

3. Smoking reduction and nicotine replacement therapy

  • Whilst there is little evidence to support unaided smoking reduction as an effective harm control measure for smokers, recent data suggest a benefit of smoking reduction when it is accompanied by use of pharmacotherapy such as nicotine replacement therapy (NRT).26
  • It has been speculated that use of NRT for smoking reduction may discourage smokers from making quit attempts or from stopping smoking as it may maintain nicotine dependence and reduce motivation to stop as smokers may be falsely reassured that they are reducing harm from smoking; however, this fear has not been borne out by the data.3,27
  • Results from studies in which smokers were randomised to either a placebo or NRT (mostly the nicotine gum or inhaler) suggest that the provision of NRT led to both sustained smoking reduction (≤ 50% of baseline consumption) and increased smoking cessation, while there was no evidence of an increase in adverse events (Figure 3).26 The causal mechanism for this effect are unclear but may be due to increasing smokers confidence in their ability to stop and reducing the reinforcing addictive potential of cigarettes thus facilitating the smoker's transition to abstinence and to help maintain abstinence.28

Figure 3. Impact of NRT on smoking reduction, smoking cessation and serious adverse events (Pooled odds ratios with 95% confidence interval). Adapted from Moore et al, 2009.26 (Click on the image to enlarge)

  • On the basis of these positive findings, the licensing of some NRT products in the UK has now been extended to allow use for temporary abstinence and smoking reduction without a specific intention to quit completely.29

References

  1. McNeill A. Harm reduction. BMJ 2004; 328(7444):885–887.
  2. Fagerstrom KO. Can reduced smoking be a way for smokers not interested in quitting to actually quit? Respiration 2005; 72(2):216–220.
  3. Beard E, McNeill A, Aveyard P, Fidler J, Michie S, West R. Use of nicotine replacement therapy for smoking reduction and during enforced temporary abstinence: a national survey of English smokers. Addiction 2011; 106(1):197–204.
  4. Fidler JA, Jarvis MJ, Mindell J, West R. Nicotine intake in cigarette smokers in England: distribution and demographic correlates. Cancer Epidemiol Biomarkers Prev 2008; 17(12):3331–3336.
  5. Joseph AM, Hecht SS, Murphy SE, Carmella SG, Le CT, Zhang Y et al. Relationships between cigarette consumption and biomarkers of tobacco toxin exposure. Cancer Epidemiol Biomarkers Prev 2005; 14(12):2963–2968.
  6. Benowitz NL. Compensatory smoking of low-yield cigarettes. In: National Cancer Institute, editor. Risks associated with smoking cigarettes with 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. 39–64.
  7. Scherer G. Smoking behaviour and compensation: a review of the literature. Psychopharmacology (Berl) 1999; 145(1):1–20.
  8. Adda J, Cornaglia F. Taxes, cigarette consumption, and smoking intensity. Am Econ Rev 2006; 96(4):1013–1028.
  9. Frost C, Fullerton FM, Stephen AM, Stone R, Nicolaides-Bouman A, Densem J et al. The tar reduction study: randomised trial of the effect of cigarette tar yield reduction on compensatory smoking. Thorax 1995; 50(10):1038–1043.
  10. Benowitz NL, Jacob P, III, Kozlowski LT, Yu L. Influence of smoking fewer cigarettes on exposure to tar, nicotine, and carbon monoxide. N Engl J Med 1986; 315(21):1310–1313.
  11. Hurt RD, Croghan GA, Wolter TD, Croghan IT, Offord KP, Williams GM et al. Does smoking reduction result in reduction of biomarkers associated with harm? A pilot study using a nicotine inhaler. Nicotine Tob Res 2000; 2(4):327–336.
  12. Godtfredsen NS, Prescott E, Vestbo J, Osler M. Smoking reduction and biomarkers in two longitudinal studies. Addiction 2006; 101(10):1516–1522.
  13. Yong HH, Borland R, Hyland A, Siahpush M. How does a failed quit attempt among regular smokers affect their cigarette consumption? Findings from the International Tobacco Control Four-Country Survey (ITC-4). Nicotine Tob Res 2008; 10(5):897–905.
  14. Hughes JR, Carpenter MJ. The feasibility of smoking reduction: an update. Addiction 2005; 100(8):1074–1089.
  15. Hughes JR, Carpenter MJ. Does smoking reduction increase future cessation and decrease disease risk? A qualitative review. Nicotine Tob Res 2006; 8(6):739–749.
  16. Broms U, Korhonen T, Kaprio J. Smoking reduction predicts cessation: longitudinal evidence from the Finnish adult twin cohort. Nicotine Tob Res 2008; 10(3):423–427.
  17. Falba T, Jofre-Bonet M, Busch S, Duchovny N, Sindelar J. Reduction of quantity smoked predicts future cessation among older smokers. Addiction 2004; 99(1):93–102.
  18. Farkas AJ. When does cigarette fading increase the likelihood of future cessation? Ann Behav Med 1999; 21(1):71–76.
  19. Meyer C, Rumpf HJ, Schumann A, Hapke U, John U. Intentionally reduced smoking among untreated general population smokers: prevalence, stability, prediction of smoking behaviour change and differences between subjects choosing either reduction or abstinence. Addiction 2003; 98(8):1101–1110.
  20. Hughes J, Lindgren P, Connett J, Nides M. Smoking reduction in the Lung Health Study. Nicotine Tob Res 2004; 6(2):275–280.
  21. 21. Hughes JR, Cummings KM, Hyland A. Ability of smokers to reduce their smoking and its association with future smoking cessation. Addiction 1999; 94(1):109–114.
  22. Godtfredsen NS, Holst C, Prescott E, Vestbo J, Osler M. Smoking reduction, smoking cessation, and mortality: a 16-year follow-up of 19,732 men and women from The Copenhagen Centre for Prospective Population Studies. Am J Epidemiol 2002; 156(11):994–1001.
  23. Simmons MS, Connett JE, Nides MA, Lindgren PG, Kleerup EC, Murray RP et al. Smoking reduction and the rate of decline in FEV(1): results from the Lung Health Study. Eur Respir J 2005; 25(6):1011–1017.
  24. Lange P, Groth S, Nyboe GJ, Mortensen J, Appleyard M, Jensen G et al. Effects of smoking and changes in smoking habits on the decline of FEV1. Eur Respir J 1989; 2(9):811–816.
  25. Pisinger C, Godtfredsen NS. Is there a health benefit of reduced tobacco consumption? A systematic review. Nicotine Tob Res 2007; 9(6):631–646.
  26. Moore D, Aveyard P, Connock M, Wang D, Fry-Smith A, Barton P. Effectiveness and safety of nicotine replacement therapy assisted reduction to stop smoking: systematic review and meta-analysis. BMJ 2009; 338:b1024.
  27. Levy DE, Thorndike AN, Biener L, Rigotti NA. Use of nicotine replacement therapy to reduce or delay smoking but not to quit: prevalence and association with subsequent cessation efforts. Tob Control 2007; 16(6):384–389.
  28. West R, Shiffman S. Fast Facts: Smoking cessation. 2nd ed. Oxford: Health Press; 2007.
  29. MHRA. MHRA Public Assessment Report: The use of nicotine replacement therapy to reduce harm in smokers.
  30. http://www.mhra.gov.uk/Safetyinformation/
    Safetywarningsalertsandrecalls/
    Safetywarningsandmessagesformedicines/CON068572     
    2010 [cited 2010 Oct. 22]; Available from:
    www.mhra.gov.uk/Safetyinformation/
    Safetywarningsalertsandrecalls/
    Safetywarningsandmessagesformedicines/CON068572

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