Experts urge caution over exercise testing study on vapers and smokers

Experts have cautioned against drawing definitive conclusions from the results of a study that suggested young people who vape perform as poorly as smokers in exercise tests, pointing out several limitations in the research methodology.

The study, presented at the European Respiratory Society Congress 2024 in Vienna, Austria, is still unpublished and not yet peer-reviewed.

Rachel Richardson, manager at the Methods Support Unit at Cochrane, highlighted the need for careful interpretation.

“This is unpublished research, and so independent scientists have not yet scrutinised the methods and the results. Peer review is a crucial part of the scientific process and it is a major concern that these findings are being widely disseminated without this scrutiny,” Richardson said.

Richardson also pointed out that the study shows an association between vaping and reduced exercise performance but does not establish causation. Other factors, such as differences in physical activity levels between the groups, could also play a role in the findings.

Richardson further noted the study’s small sample size and the lack of updated data. While the press release referenced the initial findings, the researchers have since collected data from an additional 15 participants, which will be presented at the conference, being held on 7–11 September.

Professor Kevin McConway, emeritus professor of applied statistics at The Open University, echoed the need for caution, citing the lack of detailed information about the study.

“We have a fairly brief press release and a very brief summary of the work. But the study has not yet been through a full peer review, and important details about what was actually done (or not done) are just not available, not yet anyway,” McConway noted.

McConway also warned against concluding that vaping and smoking have identical effects based on the limited data available.

“The three groups (tobacco smokers, vapers, non-smokers) would have differed in many ways apart from whether they smoked, vaped or did neither. The information we have on the study does give some details, for example of the participants’ ages, heights and weights, and of measures of lung and circulatory system function while resting. But apart from that, we have rather few details on how the groups compared. So it remains possible that the observed differences in response to exercise are actually caused, not by whether they smoke or vape, but by some other difference, perhaps in lifestyle,” McConway noted.

“It could even be that cause and effect goes in a different direction altogether. Maybe some people chose not to use tobacco or vapes because they were more involved in sport and exercise, and it’s this previous involvement in sport that is the cause of their better physiological response to exercise, rather than the fact that they chose not to smoke or vape,” he added.

“Or it could indeed be that the differences in response to exercise are in fact caused by the smoking or vaping. The issue is that we just can’t tell, at any rate on the basis of the information available.”