August 18, 2015

expert reaction to study on e-cigarette use and subsequent smoking in US teenagers

Publishing in the Journal of the American Medical Association, a group of researchers has investigated a possible connection between e-cigarettes and initiation of smoking, reporting that users of e-cigarettes were more likely than non-users to subsequently try combustible smoking products in the following year.

Prof. Peter Hajek, Professor of Clinical Psychology and Director of Tobacco Dependence Research Unit, Queen Mary, University of London, said:

“The new study does not show that vaping leads to smoking. It just shows that people who are attracted to e-cigarettes are the same people who are attracted to smoking. People who drink white wine are more likely to try red wine than people who do not drink alcohol. If the research question was turned around and the study examined whether young people who smoke are more likely to try e-cigarettes than those who never smoked, the results would of course be similar, but this would not lead to headlines saying that smoking causes e-cigarette use.

“To examine whether experimentation with e-cigarettes leads to smoking, other types of data are needed, and these are in fact available. Smoking among US high school students has been declining by some 2% per year from 2003 to 2011. Between 2011 and 2013 however, over a period of time when e-cigarette experimentation accelerated, the decline in smoking prevalence did not slow down but had in fact accelerated as well, with the number of smokers declining by further 13% over these 2 years. This observation does not prove causality, but it shows that e-cigarette experimentation is certainly not creating new smokers or slowing the decline in smoking prevalence. It may in fact be contributing to it. Despite the headlines this study will generate, there is no evidence to suggest that experimentation with vaping among non-smokers leads to even regular vaping, let alone to smoking. Vaping is strikingly non-attractive to non-smokers and virtually none progress to becoming daily vapers – unlike experimentation with cigarettes which leads to about half of experimenters becoming daily smokers. ”

Prof. Linda Bauld, Professor of Health Policy, University of Stirling, and Chair in Behavioural Research for Cancer Prevention, said:

“This is the first study to follow up a sample of young people who have never smoked but had ever tried an e-cigarette. What it found is that a very small proportion of secondary school pupils in California (less than 8.7%, 220 young people) had not smoked but had tried an e-cigarette at least once, and that this group were more likely to then have ever tried a tobacco product, including cigarettes, at 6 or 12 month follow up. The study methods are robust but include very simple measures, only asking about experimentation with both products (ever trying) than any type of frequent or established use. Future studies needs to assess regular use to draw any firm conclusions about links between e-cigarettes and tobacco smoking.

“These findings from a very small sample of young people do not suggest that e-cigarettes are contributing to a rise in youth tobacco smoking rates, as during the period of the study youth smoking in the USA is continuing to fall. However, they do show that continued wide availability of a product that kills one in two of its long term users – tobacco – means that even youth who experiment with a less harmful alternative (the e-cigarette) may still try smoking. All governments need to prioritise efforts to restrict access to and affordability of tobacco if we are to protect young people from the disease and death inflicted on previous generations by smoking.”

‘Association of Electronic Cigarette Use With Initiation of Combustible Tobacco Product Smoking in Early Adolescence’ by Leventhal et al. will be published in JAMA at 16:00 UK time on Tuesday 18th August, which is also when the embargo will lift. 

All our previous output on this subject can be seen at this weblink: http://www.sciencemediacentre.org/tag/e-cigarettes/

The SMC produced a Factsheet on e-cigarettes which is available here: http://www.sciencemediacentre.org/electronic-cigarettes/  

Declared interests

Prof. Peter Hajek: I have no links to any e-cigarette manufacturers.

Prof.  Linda Bauld chaired the programme development group on tobacco harm reduction that was responsible for producing guidance on harm reduction for the National Institute for Health and Care Excellence (NICE) in 2013.