June 26, 2017

expert reaction to review of e-cigarettes and smoking in young adults

Publishing in JAMA Pediatrics scientists report results from a systematic review and meta-analysis of longitudinal studies that assessed initial use of e-cigarettes and subsequent cigarette smoking.

Prof. Ann McNeill, Professor of Tobacco Addiction at the National Addiction Centre, Institute of Psychiatry Psychology & Neuroscience, King’s College London, said:

“Whether using e-cigarettes causes a young never smoker to go on to smoke tobacco cigarettes is important. This review does not find this.  It cannot rule out the alternative explanation that young people who are interested in trying e-cigarettes are also interested in trying tobacco cigarettes.

“This study also completely ignores the elephant in the room. E-cigarettes are known to be less harmful than tobacco cigarettes, but experts and health organisations, particularly those in countries where the original studies were carried out, are not publicly saying this. If young people think e-cigarettes and tobacco cigarettes are equally harmful, those inclined to try them will experiment with both.”

Prof. Marcus Munafò, Professor of Biological Psychology at the University of Bristol, said:

“This is a large and well conducted systematic review and meta-analysis which combines evidence from several studies. However, the main finding is already known – among young people there is an association between using e-cigarettes and smoking conventional cigarettes.

“Critically, it is not possible to establish cause and effect from studies of this kind. Although most studies attempt to adjust for potential confounders – other variables that influence both vaping and smoking – it is practically impossible to do this perfectly.”

“Therefore, it remains possible (and even plausible) that young people with, for example, a more risk-taking personality will try both vaping and smoking.”

Prof. Peter Hajek, Director of the Tobacco Dependence Research Unit at Queen Mary University of London, said:

“People who drink white wine are more likely to also try red wine than teetotallers, but common sense would not suggest that this means that removing the white will reduce the drinking of the red. The authors however make that conclusion here – because the same people try both vaping and smoking, we should curb vaping to reduce smoking. The conclusion clashes not just with logic but also with other more relevant data that suggest that limiting access to vaping is more likely to aid rather than curb the tobacco alternative.

“The article does not differentiate between young people who just tried vaping or smoking and those who became regular users. Other studies however show consistently that non-smokers who try vaping almost never progress to regular use. Trying an e-cigarette does not lead a non-smoker to vaping, let alone to smoking. It is smokers who find vaping attractive and for whom it is a gateway FROM smoking.

“In both the US and the UK, access to e-cigarettes has been accompanied by an unprecedented decline in youth smoking. Access to vaping does not generate an increase in smoking.”

* ‘Association Between Initial Use of e-Cigarettes and Subsequent Cigarette Smoking Among Adolescents and Young Adults’ by Samir Soneji et al. published in JAMA Pediatrics on Monday 26 June. 

Declared interests

Prof. Peter Hajek: “I have no links with any e-cigarette manufacturers. My research into e-cigarette safety and effects has been funded by NIHR, PHE, UKCTAS and MHRA.”

None others received.