Kimber 2021.

Study characteristics
Methods	Design: RCT Recruitment: Participants were screened via phone interviews. Setting: East London, UK Study start date: Participants recruited between December 2015 and December 2016
Participants	Total: N = 50 people who smoked combustible cigarettes and were e‐cigarette naive. Initial sample (N = 70) attended first session; all analyses were conducted on the N = 50 who returned for their 2nd and 3rd session. Cig‐a‐likes: N = 11 Tank18: N = 20 Tank6: N = 19 Inclusion criteria: Smoke daily ≥ 5 cigarettes, have smoked for ≥ 1 year, not currently using an EC, willing to abstain 1 hr before the start of the session and willing to make a quit attempt Exclusion criteria:  < 18 years, not fluent in English, pregnancy or breastfeeding, or a known neurobiological or heart condition 64% women; mean age 29.5 (SD 9.31); mean CPD 13.09 (SD 6.66), mean FTND 4.14 (SD 2.45) Motivated to quit: ‘Willing to make a quit attempt’ E‐cigarette use at baseline: No
Interventions	EC: cartridge and refillable Arm 1: cig‐a‐like (18 mg/mL) The ‘Blu’ (n = 13) and ‘TECC Go e‐cigarette’ models (n = 11) were used for the Cig‐a‐like condition, due to issues of leakages with the latter. Non‐adjustable battery power output and could be recharged, a supply of spare disposable cartridges were provided.  Arm 2: a tank model containing 18 mg/mL (Tank18) Arm 3: a tank model containing 6 mg/mL (Tank6)   For both conditions Tank18 and Tank6 the ‘Totally Wicked mini curve’ was mounted with a 2 mL capacity tank which housed a standard atomiser of 1.5 ohm resistance. E‐liquid ingredients composition and flavours were kept consistent across all conditions using the same ratio of propylene glycol and vegetable glycerin (PG/VG: 50/50) and tobacco flavour. Intervention. All 3 groups participants vaped 20 min ad libitum in 3 separate sessions (baseline, 1 and 2 weeks post‐baseline). Ahead of their baseline session, participants were instructed to abstain from smoking for an hour. Rated their craving and withdrawal symptoms (at the beginning and end of the session), before receiving instructions on how to use their EC and to vape ad libitum for 20 mins  Positive and adverse effects were measured at the end of the last puff. All vaping sessions were video‐recorded.  At the end of each session, participants were given the EC and were instructed to keep a record of the number of cigarettes smoked at the end of each day until their next and subsequent sessions. Each participant was provided with a weekly supply of either, 60–80 mL of e‐liquid in refill bottles for those in the tank conditions, or 15 cartridges for those in the cig‐a‐like condition at the end of each testing session. The session was repeated the following week, then one week later. Participants were asked to keep the device and encouraged to try and replace as many tobacco cigarettes as they could with the use of their EC.
Outcomes	Baseline, week 1, week 2 CO was measured at baseline, wk 1 and wk 2. Self‐reported CPD. Adverse events. Puff duration, puff number, inter‐puff intervals (IPI). Cigarette dependence, craving, withdrawal, and subjective effects
Study funding	This work was funded by the University of East London through a PhD studentship award. The funder had no role in the study design, collection, analysis or interpretation of data, writing the manuscript and the decision to submit the manuscript for publication.
Author declarations	CK and KS have no conflicts of interest to declare. LD has provided consultancy for the pharmaceutical industry relating to the development of smoking cessation products.
Notes	New to 2022 update
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomly allocated (using SPSS).
Allocation concealment (selection bias)	Unclear risk	No detail
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Intervention arms received equally intensive interventions.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	CO measured
Incomplete outcome data (attrition bias) All outcomes	High risk	There was a > 20% difference in FU between arms at 2 weeks. Overall 50/70 = 71.43%. Cig‐a‐like 11/24 = 45%. Tank6 19/23 = 82.61%. Tank18 20/23 = 86.96%
Selective reporting (reporting bias)	High risk	Reported on AEs but excluded those who had reported AEs (as they did not complete all sessions (due to AEs)