E-cigarette use helps smokers quit for good

Use of nicotine e-cigarettes works better than conventional nicotine replacement or behavioural therapies for smoking cessation among individuals who are attempting to quit, a study has shown.

“Nicotine e-cigarettes were associated with increased smoking abstinence in comparison with non-nicotine e-cigarettes,” the investigators said. “Furthermore, nicotine and non-nicotine e-cigarettes increased abstinence compared with conventional smoking cessation therapies.”

In this systematic review and meta-analysis, randomized controlled trials (RCTs) with a follow-up duration of ≥6 months were identified using the databases of Medline, Embase, and Cochrane Central. The most rigorous criterion of biochemically validated abstinence at maximum follow-up was the primary endpoint, and nicotine e-cigarettes vs conventional therapy was the primary comparison.

The investigators assessed publication bias using the Cochrane Risk of Bias Tool. They pooled count data across trials using random-effects models with inverse variance weighting to estimate relative risks (RRs) and 95 percent confidence intervals (CIs).

Five RCTs, including a total of 3,253 participants, met the eligibility criteria. [Am J Med 2023;136:804-813.E4]

Use of nicotine e-cigarettes, compared with conventional smoking cessation therapies, resulted in greater abstinence, defined by the most rigorous criterion of abstinence reported (RR, 1.77, 95 percent CI, 1.29‒2.44). Likewise, nicotine e-cigarettes were superior to non-nicotine e-cigarettes in improving abstinence (RR, 1.56, 95 percent CI, 1.13‒2.15).

Notably, there was a low incidence of death or serious adverse events across all RCTs at maximum follow-up.

“Overall, these data suggest e-cigarettes appear to be more efficacious than conventional nicotine replacement or behavioural smoking cessation therapies,” the investigators said. “Although currently available safety data are inconclusive, e-cigarettes may be considered for smoking cessation given the established long-term health consequences of continued smoking.”

Health hazards

The effects of e-cigarettes on a person's health remain to be known, but the potential of this tool to reduce the risks associated with smoking regular cigarettes is encouraging, as reported by the Committee on the Review of the Health Effects of Electronic Nicotine Delivery Systems. [Stratton K, et al, eds. Public Health Consequences of E-Cigarettes. Washington, DC: National Academies Press; 2018]

“At the population level, introducing unrestricted access to e-cigarettes is not without risks, as they can also serve as a gateway to smoking, especially among youths,” the investigators said. “There remains a need to better understand the long-term health effects of e-cigarette use.”

However, use of e-cigarettes is supported by many public health simulation models, estimating a net benefit to the population. [Nicotine Tob Res 2021;23:426-437; JAMA 2020;324:1835-1837]

The current meta-analysis was limited by the relatively short follow-up (12 months at most), the inherent heterogeneity between trials with respect to intervention characteristics and study protocols, the small number of included trials that prevented the quantitative assessment of publication bias, and the absence of RCTs comparing e-cigarettes alone or in combination with non-nicotine pharmacotherapies (eg, varenicline and bupropion). [J Am Coll Cardiol 2018;72:3332-3365]

“Further large RCTs are warranted to contribute additional events to future meta-analyses,” the investigators said.