Table 1.

Measures related to smoking, vaping and nicotine replacement therapy use

Smoking status Could you please tell us which of the following best applies to you now? a) I smoke cigarettes (including hand-rolled) every day b) I smoke cigarettes (including hand-rolled), but not every day c) I do not smoke cigarettes at all, but I do smoke tobacco of some kind (e.g. pipe or cigar) d) I have stopped smoking completely in the last year (i.e. since May 2015)/since the last survey in December 2014) [In Wave 4, different time spans for previous participants and new recruits; in Wave 5, May/June 2016 for all participants] e) I stopped smoking completely more than a year ago (i.e. before May 2015)/before the last survey in December 2014 [In Wave 4, different time spans for previous participants and new recruits; in Wave 5, May/June 2016 for all participants] f) I have never been a smoker Categorised as current smoker (a, b, c); ex-smoker (d, e); excluded from survey (f)

Time quit smoking How long ago did your most recent quit attempt start? By most recent, we mean the last time you tried to quit smoking a) In the last week b) More than a week and up to a month c) More than 1 month and up to 2 months d) More than 2 months and up to 3 months e) More than 3 months and up to 6 months f) More than 6 months and up to a year g) More than a year and up to 15 months h) Don’t know / can’t remember Ex-smokers categorised as 2–12 months (d–f); > 12 months (g); excluded (a–c)

Vaping status Could you please tell us which of the following best applies to you now? a) I currently vape/use e-cigarettes daily b) I currently vape/use e-cigarettes but not every day c) I have tried vaping/an e-cigarette once or a few times d) I stopped vaping/using e-cigarettes in the last year [In wave 5, since May/June 2016] e) I stopped vaping/using e-cigarettes over a year ago [In wave 5, before May/June 2016] f) I have never vaped/used e-cigarettes Categorised as daily use (a); non-daily use (b); past/ever use (c-e); never vaped (f)

Device type What electronic cigarette or vaping device do you currently use / did you use the most? a) A disposable e-cigarette or vaping device (non-rechargeable) b) An e-cigarette or vaping device that uses replaceable pre-filled cartridges (rechargeable) c) An e-cigarette or vaping device with a tank that you refill with liquids (rechargeable) d) A modular system that you refill with liquids (you use your own combination of separate devices: batteries, atomizers etc...) e) Don’t know Categorised as disposable, refillable with cartridges, don’t know (a, b, e); tanks (c); modular (d)

Nicotine strength What strengths of nicotine do you use when vaping/using your e-cigarette? a) No nicotine b) 1 -8 mg/ml c) 9-14 mg/ml d) 15-20 mg/ml e) 21-24 mg/ml f) 25 mg/ml g) Don’t know Participants selecting multiple answers (n = 12) were asked “Which of these nicotine strengths do you use most often? Please select one” with the same responses as the initial question. Responses from both questions were combined to find the strength used/used most often. For main analysis, categorised as none or unknown (a, g); 1 to 14 mg/ml (b, c); 15 mg/ml and over (d–f). For sensitivity analysis, categorised as no nicotine (a); 1 to 8 mg/ml (b); 9 to 14 mg/ml (c); 15 mg/ml and over (d–f); g excluded.

Nicotine replacement therapy (NRT) use Participants were asked three questions to determine NRT use 1. Which, if any, of the following are you currently trying to help you cut down the amount you smoke? 2. Do you regularly use any of the following in situations where you are not allowed to smoke? 3. Can I check, are you using any of the following for any reason at all? a) Nicotine gum b) Nicotine replacement lozenge/tablet c) nicotine replacement inhaler/inhalator d) Nicotine replacement nasal spray e) nicotine patch f) Electronic cigarette or vaping device 1 g) Nicotine mouthspray h) Another nicotine product i) Other, please type in [text box] j) None of these/not using anything k) Don’t know 1Not asked in question 3 Categorised as current NRT use (a–e, g in any of the three questions)