Association between electronic cigarette use and changes in quit attempts, success of quit attempts, use of smoking cessation pharmacotherapy, and use of stop smoking services in England: time series analysis of population trends

Introduction:
This text is a summary of a time series analysis study that aimed to estimate the population impact of e-cigarettes on quit smoking attempts and their success, use of smoking cessation pharmacotherapy, and use of stop smoking services in England. The study used data from the Smoking Toolkit Study and the English national health service (NHS) stop smoking services.

Key Points:

* The study found that changes in prevalence of e-cigarette use in England have been positively associated with the success rates of quit attempts.
* There was no clear association between e-cigarette use and the rate of quit attempts or the use of other quitting aids, except for NRT obtained on prescription, where the association has been negative.
* The study used ARIMAX modelling, a time series analysis approach, to explore the effect of e-cigarette use on quit smoking attempts and their success.
* The study adjusted for potential confounding variables including tobacco control policies, mass media expenditure, and smoking prevalence.
* The Smoking Toolkit Study is a series of monthly household, face-to-face, computer assisted surveys of representative samples of the population in England aged 16 years or more.
* Statistics on use of the NHS stop smoking service were obtained from the NHS Information Centre.
* The study used quarterly data on e-cigarette use among current smokers and among those who made a quit attempt.
* Prevalence of use of e-cigarettes in current smokers was obtained for each quarter by counting the number of respondents who endorsed use of e-cigarettes.
* Data were first collected in 2011; prior to this, prevalence was assumed to be stable at 0.10/o of smokers.

Main Message:
The main message of the text is that e-cigarette use in England has been positively associated with the success rates of quit attempts, and there is no clear association between e-cigarette use and the rate of quit attempts or the use of other quitting aids, except for NRT obtained on prescription, where the association has been negative. The study used a time series analysis approach to estimate the population impact of e-cigarettes on quit smoking attempts and their success, and adjusted for potential confounding variables. The study findings suggest that e-cigarettes have possibly not been responsible for the large decline in NRT obtained over the counter market. Overall, the study provides evidence that e-cigarettes have a positive impact on quit smoking success rates.

Beard, Emma, Robert West, Susan Michie, and Jamie Brown. “Association between Electronic Cigarette Use and Changes in Quit Attempts, Success of Quit Attempts, Use of Smoking Cessation Pharmacotherapy, and Use of Stop Smoking Services in England: Time Series Analysis of Population Trends.” BMJ, September 13, 2016, i4645. https://doi.org/10.1136/bmj.i4645.