September 8, 2024

expert reaction to unpublished conference abstract on vaping, smoking and exercise

An unpublished conference abstract presented at the European Respiratory Society Congress 2024 looks at the association between exercise performance and vaping/smoking.

Rachel Richardson, Manager at the Methods Support Unit at Cochrane, said:

“There are several reasons to be cautious about the findings of this study and the way in which the press release has been phrased. I list below some of the key limitations.

“Firstly, this is unpublished research, and so independent scientists have not yet scrutinised the methods and the results.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.

“Secondly, the fact that the study authors seem to have found an association between performance in exercise testing and vaping in young people cannot be interpreted to mean that vaping causes a reduced capacity for exercise. There could be many other reasons for this finding, for example, people who vape may exercise less regularly than people who do not. The authors do note in their presentation that all groups were ‘physically active’, but there could still be major differences in the amount of exercise undertaken. It is also important to note that this is a very small sample, and may not be representative of all young people who do and do not vape.

“Thirdly, the results presented in the press release are not up to date. The authors now have more data from an additional 15 participants and this will be presented at the conference.”

Prof Kevin McConway, Emeritus Professor of Applied Statistics at The Open University, said:

“It’s always frustrating to try to judge the quality of a research study, being presented at a conference, on the basis of so little information. We have a fairly brief press release, a very brief summary (abstract) of the work. In this case I’ve also seen the slides that are due to be shown at the presentation, which do add a little more (the slides are also based on data from an extra five participants per group).  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.

“The quote in the press release from Dr Filippos Filippidis of Imperial College, who was not involved in the research, begins with the important point that it’s hard, in a study like this, to know what is actually causing the differences between the groups of young people in response to testing during exercise. There are good reasons for that doubt.

“This is an observational study. The researchers made, it appears, a lot of careful physiological measurements on the study participants. (I can’t comment on whether these measurements are appropriate because I’m not an exercise physiologist.) But the researchers did not allocate young people to be cigarette smokers or vapers or non-smokers. The participants were put into these groups on the basis of the choices on using cigarettes or vapes that they had made themselves. The researchers then observed various physiological characteristics.

“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 (mostly from the slides) 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.

“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.

“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.

“I think it’s also going beyond the data that we’ve seen to conclude that the effects of tobacco smoking and vaping are very similar in their effects, as Dr Faisal says in his quote in the press release (‘In this regard, our research indicated that vaping is no better than smoking.’) At one level they perhaps are similar, but no information has been provided on how much and how often the smokers and vapers actually smoked or vaped. If, on average, the tobacco smokers smoked rather rarely, but the vapers made very heavy use of possibly illegal vapes, then it makes no real sense to try to draw conclusions on how the effects of tobacco and vapes compare, I’d say. Again, we need more information to be clear about what’s going on.”

Declared interests

Rachel Richardson: I have no interests to declare.

Prof Kevin McConway: “I am a Trustee of the SMC and a member of its Advisory Committee.  My quote above is in my capacity as an independent professional statistician.”