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Evidence summaries

E-Cigarettes and Smoking Cessation in Real-World Settings

E-cigarettes may be effective for cigarette smoking cessation compared with nicotine replacement therapy or no use of e-cigarettes. However, there is a high risk of continued e-cigarette use at 6 months or longer. Level of evidence: "C"

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

Summary

A systematic review with meta-analyses 5 included 19 studies with a total of 7787 participants. The pooled prevalence of continued e-cigarette use at 6 months or longer was 54% (95% CI 46% to 61%, I2 =86%, n=1482) in participants assigned to e-cigarette conditions. Of participants who had quit combustible cigarettes overall 70% were still using e-cigarettes at 6 months or longer (95% CI 53% to 82%, I2 =73%, n=215).

A systematic review and meta-analysis 6 included 26 cohort studies and 7 RCTs. No quality evidence for an association between e-cigarette use and smoking cessation was found. A random-effects meta-analysis in cohort studies showed a pooled unadjusted odds ratio (OR) for smoking cessation among baseline e-cigarette users compared with baseline non-users of 0.97 (95% CI 0.67 to 1.40, n=39 147), while the adjusted OR was 0.90 (95% CI 0.63 to 1.27). The pooled odds ratio for smoking cessation in RCTs was 1.78 (95% CI 1.41 to 2.25). The evidence was graded as very low or low.

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 Cochrane review [Abstract] 4 included 88 studies (45 RCTs) with a total of 27 235 participants. Only 10 studies were rated at low risk of bias. Quit rates (with biochemical validation) were higher in people randomized to nicotine e-cigarettes than in those randomized to NRT (RR 1.59, 95% CI 1.29 to 1.93; 7 studies, n=2544). Quit rates with nicotine e-cigarettes were better compared to non-nicotine e-cigarettes at 6-12 months (RR 1.46, 95% CI 1.09 to 1.96, 6 RCTs, n=1613).

Clinical comments

Note

Date of latest search: 2024-08-16

    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]
    • Lindson N, Butler AR, McRobbie H, et al. Electronic cigarettes for smoking cessation. Cochrane Database Syst Rev 2024;1(1):CD010216[PubMed]
    • Butler AR, Lindson N, Fanshawe TR, et al. Corrigendum to "Longer-term use of electronic cigarettes when provided as a stop smoking aid: Systematic review with meta-analyses" [Preventive Medicine, Volume 165, Part B, December 2022, 1-12/107182]. Prev Med 2023;167():107406 [PubMed]
    • Hedman L, Galanti MR, Ryk L, et al. Electronic cigarette use and smoking cessation in cohort studies and randomized trials: A systematic review and meta-analysis. Tob Prev Cessat 2021;7():62 [PubMed]

Primary/Secondary Keywords