July 26, 2017

expert reaction to study looking at e-cigarette use in adult smokers and smoking cessation in the US

A new study published in The BMJ looks at e-cigarette use in US adult smokers and smoking cessation rates.

Prof. Linda Bauld, Professor of Health Policy, University of Stirling, said:

“This is the largest observational study carried out anywhere in the world so far examining trends in smoking cessation amongst adults who have used e-cigarettes.  It finds that those who had used an e-cigarette were significantly more likely to have stopped smoking compared to those who had not, and also found that the rate of those stopping smoking in the USA increased between the period when e-cigarette use was rare (2010-2011) to when it was much more common (2014-15).

“Similar trends have been observed in the UK, but with much smaller samples.  The fact that patterns are similar between two countries that permit e-cigarette use (and do not heavily regulate them) is important.  It suggests that e-cigarettes may have acted to accelerate existing downwards trends in smoking, and this needs to be carefully considered by governments in other countries who still ban these devices or make them very difficult for smokers to obtain.  To put it another way, e-cigarettes may have put the pedal to the metal on the road to a smokefree future.

“The survey only assesses stopping smoking for at least three months.  However, stopping for this long is associated with a much higher chance of becoming a non smoker for good.  Likewise it did not ascertain what types of e-cigarette devices smokers were using, or how frequently, both factors that have been shown in other studies to be important for smoking cessation.  More research is needed with similarly large samples, but with more detailed measures, to examine longer term trends.”

Dr Jamie Hartmann-Boyce, Senior Researcher in Health Behaviours, University of Oxford, and Managing Editor of the Cochrane Tobacco Addiction Group, said:

“This study from the US uses results from a large population survey to investigate associations between the use of e-cigarettes and quitting smoking.  The authors find that e-cigarette users were more likely than non-users to try to quit smoking, and to succeed in doing so.  Observational studies of this type have several limitations, the main one being that it is difficult to establish causation – for example, was it the electronic cigarettes that caused people to stop smoking or was it something else about the e-cigarette users that made them more likely to quit?  For that reason it is particularly useful to view the results in the context of other studies.  Though findings from other observational studies have found varying results, findings from this study are promising and are consistent with a growing body of evidence from randomized controlled trials and other study types suggesting that electronic cigarettes with nicotine may help people stop smoking.”

* Paper: ‘E-cigarette use and associated changes in population smoking cessation: evidence from US current population surveys’ by Shu-Hong Zhu et al. will be published in the BMJ at 23:30 UK time on Wednesday 26 July 2017, which is also when the embargo will lift. 

Editorial: ‘Rise in e-cigarette use linked to increase in smoking cessation rates’ by Christopher Bullen will be published in the BMJ at 23:30 UK time on Wednesday 26 July 2017, which is also when the embargo will lift. 

Declared interests

Prof. Linda Bauld: “None to declare.”

Dr Jamie Hartmann-Boyce: “I don’t have any conflicts of interest to declare.”