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Are ‘dual users’ who smoke and use e-cigarettes interested in using varenicline to stop smoking altogether, and can they benefit from it? A cohort study of UK vapers
  1. Peter Hajek,
  2. Sarrah Peerbux,
  3. Anna Phillips-Waller,
  4. Charlotte Smith,
  5. Kate Pittaccio,
  6. Dunja Przulj
  1. Health & Lifestyle Research Unit, Queen Mary University of London, London, UK
  1. Correspondence to Dr Dunja Przulj; d.przulj{at}


Objectives Smokers who use e-cigarettes (EC) do so mostly to stop smoking, but many continue to use both products. It is not known whether these ‘dual users’ are interested in stop-smoking medications and whether they can benefit from them.

Setting, participants and measures Dual users were recruited over social media and posted study questionnaire and saliva kits at baseline, 3 and 6 months. Those interested in varenicline were posted the medication and received weekly calls over the first 6 weeks, followed by three calls at fortnightly intervals.

Results Of 204 participants, 124 (61%, CI=54% to 68%) expressed interest in receiving varenicline and 80 (39%, CI=32% to 45%) started varenicline (varenicline users, VU). VU were more dependent smokers (F=6.2, p=0.01) with higher cigarette consumption (F=8.7, p<0.01) who were using stronger nicotine e-liquids (F=13.9, p<0.001) than dual users not opting for varenicline (varenicline non-users, VN). In terms of abstinence for at least 3 months at the 6-month follow-up, VU were more likely than VN to report abstinence from smoking (17.5% vs 4.8%, p=0.006, RR=3.6, CI:1.4 to 9.0), vaping (12.5% vs 1.6%, p=0.007, RR=7.8, CI:1.7 to 34.5) and both smoking and vaping (8.8% vs 0.8%, p=0.02, RR=10.9, CI:1.4 to 86.6). The differences were significant across sensitivity analyses (RRs=4.9 to 14.0; p=0.02 to p<0.001 at 3 months; RRs=3.0 to 14.0; p=0.01 to p<0.001 at 6 months). VU reported a greater reduction in enjoyment of vaping by the end of the varenicline use period (F=4.1, p=0.04) and recorded a significantly greater reduction in nicotine intake than VN at 3 months (F=13.9, p<0.001) and 6 months (F=26.5, p<0.001).

Conclusion Varenicline offered to dual users is likely to promote successful abstinence from both smoking and vaping, although a randomised trial is needed to confirm this. Among dual users who want to stop smoking, there seems to be a high level of interest in smoking-cessation treatments.

  • vaping
  • varenicline
  • e-cigarettes
  • smoking cessation

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  • Contributors All authors (PH, DP, SP, AP-W, CS and KP) contributed to the planning and conduct of the work, and DP, PH, KP and SP contributed to the reporting of the work. PH and DP are responsible for the overall content as guarantors. The guarantors accept full responsibility for the work and/or the conduct of the study, had access to the data and controlled the decision to publish. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding The study was funded by an investigator-initiated grant from Pfizer. The funder was not involved in the study design, conduct, or data analysis.

  • Competing interests All authors declare: support from Pfizer for the work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and PH has provided consultancy to manufacturers of stop-smoking medications.

  • Ethics approval The study was approved by the NHS Research Ethics Committee, England (reference number: 15/WM/0334).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Data are available upon request from the corresponding author.

  • Patient consent for publication Not required.

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