Although e-cigarettes could drive smoking cessation, questions on long-term impact remain

Key takeaways:

• E-cigarettes are tied to smoking cessation, studies show.
• However, questions such as long-term effectiveness and how they perform against other therapies remain.

BOSTON — Although recent evidence suggests that e-cigarettes may be an effective smoking cessation tool, further studies are needed to evaluate their efficacy and safety, according to an expert.

As Healio previously reported, e-cigarette use has seen substantial rises over the last decade. Between 2013 to 2021:

• the prevalence of those who have ever used e-cigarettes increased from 32% to 52.7%; and
• the prevalence of everyday e-cigarette use increased from 1.2% to 8.3%.

“I do believe that e-cigarettes can be used for adult smokers as a form of tobacco reduction,” Rachel E. Simon, MD, a clinical assistant professor of medicine and psychiatry at the New York University Grossman School of Medicine, said at the ACP Internal Medicine Meeting.

According to Simon, e-cigarettes may be more attractive to users given their similarity to combustible cigarettes.

“They’ve really evolved since 2007,” she said. “The reason why Juul really took off was that it used a new type of nicotine called nicotine salt, which ... allows for a higher concentration of nicotine delivery than the prior e-cigarettes."

“The nicotine delivery of Juul is really comparable to a combustible cigarette,” Simon added.

E-cigarettes tied with improved quit rates

During the presentation, Simon highlighted recent research evaluating the impact of e-cigarettes on smoking cessation compared or combined with other therapies.

In one study, published in The New England Journal of Medicine in 2019, researchers randomly assigned 886 adult smokers to combination nicotine replacement therapy (NRT) or e-cigarettes. The primary outcome was abstinence at 52 weeks.

The study showed that 18% of e-cigarette users were abstinent at 1 year vs. 9.9% of NRT users. Another important finding from this research was that 80% of those in the e-cigarette group who were abstinent were still using e-cigarettes at the 1-year mark, Simon said.

Meanwhile, in a 2019 Lancet Respiratory Medicine pragmatic, randomized study, 1,100 adult smokers were assigned to either a nicotine patch combined with nicotine e-cigarettes, a nicotine patch with non-nicotine e-cigarettes or a nicotine patch only over a 6-month period.

The findings “were less robust than the previous one,” Simon said. At 6 months, 7% of participants in the nicotine e-cigarette and patch group were abstinent compared with 4% in the nicotine-free e-cigarette and patch group and 2% for the patch only group. The trial showed that combining nicotine products and nicotine e-cigarettes “can lead to a modest improvement in smoking cessation” over patches or e-cigarettes alone, Simon explained.

Certainty of evidence has improved

According to Simon, the quality of evidence on the associations between e-cigarettes and smoking cessation has increased in the last couple years.

She cited a living systematic review published in the Cochrane Database of Systematic Reviews that found more reports are changing the quality of evidence from moderate certainty to high certainty evidence that e-cigarettes with nicotine increase quit rates vs. non-nicotine e-cigarettes and NRT.

“They’ve also looked at adverse effects and haven’t really been able to find a difference in adverse effects,” she said. “It is notable that they didn’t detect evidence of serious harms in the studies.”

Unanswered questions about continued e-cigarette use

Although multiple studies have demonstrated quality evidence favoring e-cigarettes’ impacts on quit rates, there are still questions about the products’ effectiveness and long-term effects.

In a 2019 Preventive Medicine systematic review and analysis of 19 studies, researchers found that 54% of people given e-cigarettes continued to use them at 6 months, and 70% of those who successfully quit combustible cigarettes continued to use e-cigarettes.

“What this shows me is that on one hand, you can say that maybe they drive success as a smoking cessation tool by preventing relapses,” Simon said. “Of course, [there are] concerns over long-term health risks and if long-term vaping may facilitate relapse of smoking.”

There is some evidence that c-cigarettes may increase heart rate and BP and cause respiratory symptoms, although the risks appear to be lower than those associated with cigarette smoking, according to Simon. There is no available evidence on whether e-cigarettes are linked to cancer.

Ultimately, “more trials are needed for safety and efficacy,” Simon concluded. “Unanswered questions we have about smoking cessation [are] the efficacy of newer fourth-generation products — as well as disposable e-cigarettes — and then comparing it with other known smoking cessation pharmacotherapy.”

References:

• Auer R, et al. N Engl J Med. 2024;doi:10.1056/NEJMoa2308815.
• Butler A, et al. Prev Med. 2022;doi:10.1016/j.ypmed.2022.107182.
• Hajek P, et al. N Engl J Med. 2019;doi:10.1056/NEJMoa1808779.
• Lindson N, et al. Cochrane Database Syst Rev. 2023;doi:10.1002/14651858.CD010216.pub8.
• Simon R. E-cigarettes: Friend or foe? Presented at: ACP Internal Medicine Meeting; April 18-20, 2024; Boston.
• Walker N, et al. Lancet Respir Med. 2019;doi:10.1016/S2213-2600(19)30269-3.