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BMJ Open. 2018 Jun 19;8(6):e016046. doi: 10.1136/bmjopen-2017-016046.

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

Author information

Cancer Research UK Health Behaviour Research Centre, University College London, London, UK.
Research Department of Educational, Clinical and Health Psychology, University College London, London, UK.



Many smokers use e-cigarettes and licensed nicotine replacement therapy (NRT), often in an attempt to reduce their cigarette consumption. We estimated how far changes in prevalence of e-cigarette and NRT use while smoking were accompanied by changes in cigarette consumption at the population level.


Repeated representative cross-sectional population surveys of adults aged 16+ years in England.


We used Autoregressive Integrated Moving Average with Exogeneous Input (ARIMAX) modelling of monthly data between 2006 and 2016 from the Smoking Toolkit Study. Prevalence of e-cigarette use and NRT use in current smokers, and specifically for smoking reduction and temporary abstinence, were input variables. Mean daily cigarette consumption was the dependent variable. Analyses involved adjustment for mass media expenditure and tobacco-control policies.


No statistically significant associations were found between changes in use of e-cigarettes (β -0.012, 95% CI -0.026 to 0.002) or NRT (β 0.015, 95% CI -0.026 to 0.055) while smoking and daily cigarette consumption. Neither did we find clear evidence for an association between e-cigarette use (β -0.010, 95% CI -0.025 to 0.005 and β 0.011, 95%-0.027 to 0.004) or NRT use (β 0.006, 95%-0.030 to 0.043 and β 0.022, 95%-0.020 to 0.063) specifically for smoking reduction and temporary abstinence, respectively, and changes in daily cigarette consumption.


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.


arimax; e-cigarette; nrt; smoking; time series

[Indexed for MEDLINE]
Free PMC Article

Conflict of interest statement

Competing interests: RW undertakes consultancy and research for and receives travel funds and hospitality from manufacturers of smoking cessation medications but does not, and will not take funds from e-cigarettes manufacturers or the tobacco industry. RW and SM are honorary co-directors of the National Centre for Smoking Cessation and Training. RW is a Trustee of the stop-smoking charity, QUIT. RW’s salary is funded by Cancer Research UK. SM’s salary is funded by Cancer Research UK and by the National Institute for Health Research (NIHR)’s School for Public Health Research (SPHR). EB and JB have received unrestricted research funding from Pfizer. EB and JB are funded by CRUK. EB is also funded by NIHR’s SPHR and JB by the Society for the Study of Addiction. RW has received travel funds and hospitality from, and undertaken research and consultancy for pharmaceutical companies that manufacture or research products aimed at helping smokers to stop. These products include nicotine replacement therapies, Champix (varenicline) and Zyban (bupropion). This has led to payments to him personally and to his institution.

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