REVIEW OF: Pierce JP et al, JAMA Network Open 2021;4(10):e2128810

STUDY TYPE: Cohort study

Mounting evidence suggests that ­e-cigarettes are effective for smoking cessation—nearly twice as effective as nicotine replacement therapy (see CATR May/Jun 2020 for a review of a prominent randomized controlled trial). While health authorities in some countries, such as the UK, now recommend e-cigarettes for smoking cessation, US entities like the FDA and the CDC have been far more cautious, arguing that the evidence is still preliminary and that the potential harms of e-cigarettes are not fully understood.

Recently, a large survey of US cigarette smokers added a note of caution to advocacy of e-cigarettes. While most clinical trials have focused on e-cigarettes as smoking cessation aids, in this survey researchers asked a different question: Are e-cigarettes a viable strategy to prevent return to cigarette smoking once someone has quit?

Researchers used data from the US Population Assessment of Tobacco and Health study, a large longitudinal survey of a nationally representative group of cigarette smokers. Participants were surveyed about their cigarette smoking habits at three time points—baseline, follow-up at one year, and follow-up at two years. Researchers examined the participants who had quit cigarette smoking by the time of the first follow-up and determined which strategy they had used to do so: remaining tobacco free, using an e-cigarette, or switching to some other tobacco product. For the purposes of this survey, participants who used e-cigarettes were not counted as tobacco free, a choice made to adhere to USDA definitions (Munajo M, Nicotine Tob Res 2019;21(3):267).

Of the 13,604 participants who filled out all three surveys, 9.4% (n = 1228) had quit cigarette smoking between the baseline survey and the first follow-up a year later. Of these recent former cigarette smokers, 62.9% had used a completely tobacco-free strategy, 22.8% had switched to e-cigarettes, 10.5% had switched to cigars, and 9.7% had switched to some other form of tobacco. A handful of patients used multiple forms of tobacco, which is why the percentages add up to more than 100%.

As expected, many of the participants who had quit cigarette smoking at the first follow-up had returned to cigarettes by the second follow-up a year later. However, researchers did find a difference between quit strategies; namely, tobacco-free participants fared better than those who had switched to e-cigarettes or another form of tobacco. The comparative quit rates at the two-year mark were 50.5% for the tobacco-free group, 41.6% for participants who used e-cigarettes, and 40.7% for those who used combustible tobacco products such as cigars, cigarillos, pipes, or hookahs. Overall, the rate of returning to cigarette smoking was 8.5% higher among those who had switched to ­e-cigarettes or another tobacco product compared to those who stayed tobacco free.

CARLAT TAKE

Take these results with a pinch of salt. Unlike the trials demonstrating the efficacy of e-cigarettes for smoking cessation, this was not a randomized clinical trial and there was no way to verify participant self-reports. Nonetheless, the results suggest that tobacco-free strategies may be more effective in the long term over e-cigarettes. We await a clinical trial testing this hypothesis before drawing definitive conclusions.