Vaping and quitting smoking: New study sparks debate as experts question findings

A recent cohort study that examined the association between vaping and smoking cessation rates has sparked debate among experts in the tobacco harm reduction field.

While the findings suggest that vaping may prolong smoking and nicotine dependence, experts have raised concerns about the study’s methodology and its alignment with existing evidence.

The study, published in JAMA Network Open, analysed data from 6,013 cigarette smokers in the US, comparing smoking cessation rates between those who vaped daily, nondaily, or not at all. The results indicated that nondaily vaping was associated with a 5.3 percentage point reduction in smoking cessation rates compared to non-vapers, while daily vaping showed no statistically significant difference.

Additionally, abstinence from both smoking and vaping was significantly lower among daily and nondaily vapers, with reductions of 14.7 and 7.2 percentage points, respectively. The authors concluded that vaping may prolong smoking and nicotine dependence among US smokers.

Dr Jamie Hartmann-Boyce, assistant professor of health policy and management at the University of Massachusetts Amherst, highlighted the study’s strengths and limitations. She noted that the authors used a large, representative US survey and accounted for a range of confounders, such as interest in quitting, income, and age. However, she cautioned that the observational nature of the study means it cannot establish causality.

“The type of methods they use mean they can talk about associations – whether something is more or less likely – but not about causal relationships. This research cannot establish whether e-cigarettes cause more or fewer people to stop smoking,” Dr Hartmann-Boyce said.

She also pointed out that the study’s conclusions appear to contradict the “large, high certainty body of evidence from randomised controlled trials” which show that nicotine e-cigarettes help people quit smoking.

“The authors conclude that these data ‘suggest vaping prolongs smoking and nicotine dependence among US smokers.’ As noted above, substantial randomised controlled trial evidence – considered the gold standard – shows the opposite – namely that when you give people who smoke e-cigarettes, it helps them quit smoking,” Dr Hartmann-Boyce said.

Professor Peter Hajek, director of the health and lifestyle research unit at Queen Mary University of London, raised concerns about the study’s methodology, arguing that the comparison between vapers and non-vapers was inherently skewed because the study excluded vapers who successfully quit smoking.

“The study, like several earlier ones, compared future smoking cessation in people who at baseline did and did not use vapes BUT SMOKED and reports that vaping does not help with quitting smoking,” Prof Hajek explained.

“This raises a question of how is that possible when randomised controlled trials as well as epidemiological data show that vaping is one of the most effective ways there are of helping smokers quit. The answer is that the study used a method that automatically generates skewed results. In the vaping group, only those unable to stop smoking despite using vapes were included. Vapers who stopped smoking were excluded. This makes it an obviously unfair comparison, a bit like staging a competition between two schools after removing the best competitors from one of them.”

Dr Hartmann-Boyce emphasised the importance of interpreting the results cautiously. “The most important limitation is that this is an observational data set, and the techniques they use cannot establish causality,” she said. “There could be additional unmeasured confounders which affect relationships between vaping and subsequent smoking cessation.”