Is prevalence of e-cigarette and nicotine replacement therapy use among smokers associated with average cigarette consumption in England? A time-series analysis

Introduction:
This text is a summary of a research study examining the association between e-cigarette and nicotine replacement therapy (NRT) use and cigarette consumption in England. The study used time-series analysis to account for underlying trends and confounding factors. The key points and main message of the study are summarized below.

Key points:

* The study found no significant association between changes in e-cigarette or NRT use and daily cigarette consumption.
* There was also no clear evidence for an association between e-cigarette or NRT use specifically for smoking reduction or temporary abstinence and changes in daily cigarette consumption.
* The study used data from the Smoking Toolkit Study, a monthly survey of a representative sample of adults in England, between 2006 and 2016.
* Prevalence of e-cigarette use among smokers increased from negligible use in 2006 to 17.1% in 2016, while prevalence of NRT use for harm reduction decreased from 12.2% to 6% during the same period.
* The study controlled for a number of tobacco-control policies and mass media expenditure.
* The analysis used Autoregressive Integrated Moving Average with Exogeneous Input (ARIMAX) modelling, which is a time-series analysis method that takes into account underlying trends, the effect of other tobacco-control interventions, autocorrelation, and possible lag effects.
* Sensitivity analyses were conducted to examine the effect of focusing only on daily e-cigarette and NRT use.

Main message:
The main message of the study is that if use of e-cigarettes and licensed NRT while smoking acted to reduce cigarette consumption in England between 2006 and 2016, the effect was likely very small at a population level. This is an important finding for regulators to consider, as it suggests that e-cigarettes and NRT may not be effective tools for reducing cigarette consumption at a population level. However, it is important to note that the study does not rule out the possibility that e-cigarettes and NRT may be effective for individual smokers seeking to reduce their cigarette consumption.

Beard E, Brown J, Michie S,et al. Is prevalence of e-cigarette and nicotine replacement therapy use among smokers associated with average cigarette consumption in England? A time- series analysis. BMJ Open 2018;8:e016046. doi :10.1136/ bmjopen- 2017-016046