June 13, 2016

expert reaction to study on e-cigarettes and future cigarette use

The effect of e-cigarettes on the risk of taking up smoking is the subject of a paper published in the journal Pediatrics which reports that youths who never smoked but use e-cigarettes may have an increased risk of subsequently taking up smoking when they are legally allowed to purchase tobacco products.

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

“This study is disappointing. The authors measured frequency of e-cigarette use at baseline but did not report it, simply using an ever use measure which could simply be one puff on an e-cigarette.

“The authors seem to argue that trying one puff of an e-cigarette caused some young people to try tobacco smoking within the next 16 months. If so, we would be seeing large increases in tobacco smoking, but instead we are seeing marked declines in youth tobacco smoking since e-cigarettes came on the market. This suggests e-cigarettes are actually helping young people not to smoke tobacco cigarettes (something this study did not even consider).

“They also make a lot of a finding that that some youth who had tried e-cigarettes at baseline but felt that they were not susceptible to tobacco cigarette smoking, subsequently went on to try tobacco cigarettes. Instead, the fact that they had tried e-cigarettes and this didn’t affect their feelings about using tobacco, suggests that it wasn’t the e-cigarettes that made them try tobacco smoking at some point over the next 16 months. Indeed the authors only took into account a few of the many factors that have been shown to influence tobacco smoking uptake in the rapidly changing environments of young people.

“The gateway hypothesis in the addictions field is frequently used but is highly contested as it has a poor evidence base in general. This study does nothing to strengthen that evidence base.”

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

“The authors misinterpret their findings. Like several previous studies of this type, this one just shows that people who try things, try things.

“To assess whether e-cigarette experimentation by adolescents encourages smoking, one has to examine whether an increase in e-cigarette experimentation is accompanied by an increase in smoking on the population level. Such data are available and they show that as e-cigarette experimentation increased, smoking rates in young people have gone down. In fact the decline in youth smoking over the past few years has been faster than ever before.

“This does not necessarily mean that e-cigarette experimentation prevents the uptake of smoking (although this is possible), but there is a clear and strong evidence that such experimentation does not contribute to smoking uptake. The key bit of information in this context is that non-smokers almost never progress to regular use of nicotine-containing e-cigarettes. Adolescents try them and leave them alone. E-cigarettes do not lure non-smoking adolescents even to vaping – let alone to smoking.”

‘E-Cigarettes and Future Cigarette Use’ by Jessica Barrington-Trimis et al. published in Pediatrics on Monday 13 June.

Declared interests

Prof. Hajek: “I received research funding and provided consultancy for manufacturers of stop-smoking medications (nicotine replacement products and varenicline). I have no links with any e-cigarette manufacturers, my research into the safety and effects of e-cigarettes is funded by MHRA, PHE, NIHR and UKCTAS.”

Prof. McNeill: None declared