March 5, 2025

expert reaction to a cohort study looking at the association between vaping and rates of smoking cessation and tobacco abstinence

A cohort study published in JAMA Network Open looks at the association between vaping and smoking cessation rates. 

Dr Jamie Hartmann-Boyce, Assistant Professor of Health Policy and Management, University of Massachusetts Amherst, said:

Is this good quality research?  Are the conclusions backed up by solid data?

“The authors do a thorough job of investigating results from a large, representative US survey. 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.

How does this work fit with the existing evidence?

“There is a large, high certainty body of evidence from randomized controlled trials that nicotine e-cigarettes help people quit smoking. Randomized controlled trials are considered the best way to establish the effects of an intervention, where feasible. 

Have the authors accounted for confounders? Are there important limitations to be aware of?

“The authors have accounted for a large range of confounders, but rightly note that there could be additional unmeasured confounders which affect relationships between vaping and subsequent smoking cessation. The most important limitation is that this is an observational data set, and the techniques they use cannot establish causality.

What are the implications in the real world?  Is there any overspeculation?  

“The authors conclude that these data “suggest vaping prolongs smoking and nicotine dependence among US smokers.” As noted above, substantial randomized 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.”

Prof Peter Hajek, Professor of Clinical Psychology, and Director of the Health and Lifestyle Research Unit, Queen Mary University of London (QMUL), said:

“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. 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.”

‘Daily or Nondaily Vaping and Smoking Cessation Among Smokers’ by Quash et al. was published in JAMA Network Open at 16:00 UK time on Wednesday 5th February.

DOI:10.1001/jamanetworkopen.2025.0089

Declared interests

Dr Jamie Hartmann-Boyce “I receive research funding for related work from Cancer Research UK and the NIH-FDA in the US.”

Prof Peter Hajek “No COI”