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Evidence summaries

E-Cigarettes and Smoking Cessation in Real-World and Clinical Settings

E-cigarettes may not be effective for smoking cessation compared with no use of e-cigarettes. Level of evidence: "C"

The quality of evidence is downgraded by study quality and heterogeneity.

Summary

A systematic review 1 included 38 studies; and all 20 studies with control groups (15 cohort studies, 3 cross-sectional studies, and 2 clinical trials) were included in random effects meta-analysis and sensitivity analyses (41 601 participants). Odds of quitting cigarettes were 28% lower in those who used e-cigarettes compared with those who did not use e-cigarettes (odds ratio [OR] 0.72, 95% CI 0.57 to 0.91). Association of e-cigarette use with quitting did not significantly differ among studies of all smokers using e-cigarettes (irrespective of interest in quitting cigarettes) compared with studies of only smokers interested in cigarette cessation (OR 0.63, 95% CI 0.45 to 0.86 vs 0.86, 0.60 to 1.23; p=0.94). Other study characteristics (design, population, comparison group, control variables, time of exposure assessment, biochemical verification of abstinence, and definition of e-cigarette use) were also not associated with the overall effect size. Only a few studies used biochemical verification. There were no trials with head-to-head comparisons of e-cigarettes with approved therapies.

A study 2 analyzed the association of e-cigarette use and smoking abstinence in a population of smokers accessing standard smoking cessation treatment (nicotine replacement therapy [NRT] plus behavioral counseling) for up to 26 weeks. Of the 6526 participants who completed a 3-month follow-up, 18.1% reported using an e-cigarette while in treatment. The majority of e-cigarette users (78.2%) reported using an e-cigarette for smoking cessation. At 3-month follow-up, e-cigarette use was negatively associated with abstinence after controlling for confounders (adjusted odds ratio 0.706, p < .001, 95% CI 0.607 to 0.820), as well as at 6-month follow-up (aOR 0.502, p < .001, 95% CI 0.393 to 0.640).

A study 3 including 715 participants assessed quitting behaviors among a cohort of dual users (cigarettes and e-cigarettes) and exclusive cigarette smokers for cigarette smoking reduction, quit attempts, abstinence from cigarettes, and abstinence from all tobacco products. No difference in reduction of cigarette consumption over time was noted between groups. Rates of reporting an attempt to quit all tobacco products (≥ 24 hours of not using any tobacco in an attempt to quit) also did not differ by group. Compared to cigarette smokers, dual users were more likely to report abstinence from cigarettes at 6 months (OR = 2.54, p = .045) but not at 12 or 18 months. There was no significant difference in abstinence from all tobacco products by group at 6, 12, or 18 months.

A Cochrane review [Abstract] 4 included 61 studies with a total of 16 759 participants. Quit rates (with biochemical validation) were higher in people randomized to nicotine e-cigarettes than in those randomized to NRT (RR 1.53, 95% CI 1.21 to 1.93; 4studies, n=1924). In 2 trials, there were no difference in carbon monoxide.

Clinical comments

Note

Date of latest search: 2020-04-12

    References

    • Kalkhoran S, Glantz SA. E-cigarettes and smoking cessation in real-world and clinical settings: a systematic review and meta-analysis. Lancet Respir Med 2016;4(2):116-28. [PubMed]
    • Zawertailo L, Pavlov D, Ivanova A et al. Concurrent E-Cigarette Use During Tobacco Dependence Treatment in Primary Care Settings: Association With Smoking Cessation at Three and Six Months. Nicotine Tob Res 2017;19(2):183-189. [PubMed]
    • Sweet L, Brasky TM, Cooper S et al. Quitting Behaviors Among Dual Cigarette and E-Cigarette Users and Cigarette Smokers Enrolled in the Tobacco User Adult Cohort. Nicotine Tob Res 2019;21(3):278-284. [PubMed]
    • Hartmann-Boyce J, McRobbie H, Butler AR et al. Electronic cigarettes for smoking cessation. Cochrane Database Syst Rev 2021;9():CD010216. [PubMed]

Primary/Secondary Keywords