Strasser 2016.

Study characteristics
Methods	Design: Randomized, factorial trial (Participants were randomized to one of the 5 brands of e‐cigarettes – although only 4 brands analyzed) Recruitment: Media ads Setting: Recruitment from the community, study took place at University, USA. Study start date/Study end date: Not specified.
Participants	Total N: Analysis based on 24 (28 originally recruited, but the first 4 participants enrolled experienced malfunctioning NJOY e‐cigs and withdrew – the project was removed from the market before the 5th participant was randomized) N per arm: blu: 6; Green Smoke: 6; V2: 6; White Cloud: 6 Inclusion criteria: Age 18 to 65 and self‐reported smoking at least 10 cigarettes per day. Exclusion criteria: Use of other tobacco or nicotine‐containing products, including e‐cigarettes (no more than 3 previous episodes of use and not currently using) Current diagnosis or evidence of substance abuse or dependence or major depression Current or history of psychotic or bipolar disorder History of suicide attempt History of cancer or cardiovascular disease Uncontrolled hypertension Use of smoking cessation medications Any current plans to try to quit smoking Current pregnancy or lactation Inclusion based on specific population characteristic: Not applicable 29% women; mean age 43.3; mean cpd 17; mean FTND 3.7 Motivated to quit: Participants had no current plans to try to quit smoking (eligibility criterion) E‐cigarette use at baseline: No more than 3 previous episodes of use and not currently using (eligibility criterion)
Interventions	EC: Cig‐a‐like All participants received nicotine EC and were instructed to use them exclusively for 9 days The 5 brands selected, including brand reported nicotine levels, were: (1) NJOY (18mg nicotine) – this brand was discontinued and not analyzed as the e‐cigs provided malfunctioned; (2) V2, 18 mg nicotine; (3) Green Smoke, 18.9 ‐ 20.7 mg nicotine; (4) blu, 20 ‐ 24mg nicotine; and (5) White Cloud, 23 ‐ 24 mg nicotine. Each brand advertised the delivery of the same level of nicotine (appropriate for about a pack/day smoker), provided the standard tobacco flavor (no other flavors made available), and used a disposable cigarette‐like device
Outcomes	Day 10 is the only testing point of interest for us but participants were also tested at days 1 and 5 Adverse events and biomarkers: breath CO direct effects of nicotine (e.g. dizzy, nauseas, headache) ‐ visual analogue scale with a single word scored from 0 (not at all) to 100 (extremely). Total scores were summed such that higher scores indicated negative responses Other outcomes measured: e‐cigarette use direct effects of the e‐cigarette (e.g. satisfying, calming, pleasant, smoke another right now) ‐ visual analogue scale with a single word scored from 0 (not at all) to 100 (extremely). Total scores were summed such that higher scores indicated positive responses cotinine withdrawal and craving
Study funding	“National Cancer Institute (NCI) of the National Institutes of Health (NIH) and FDA Center for Tobacco Products (CTP) under Award Number P50CA179546, as well as grants from the National Cancer Institute (P50 CA143187, P30 CA16520, and P30 DA12393)”
Author declarations	“Dr Benowitz has served on scientific advisory boards for Pfizer and GlaxoSmithKline related to smoking cessation medications and has been an expert witness in litigation against tobacco companies. Dr Schnoll receives medication and placebo free of charge from Pfizer and has provided consultation to Pfizer and GlaxoSmithKline. These companies had no involvement in this study. Dr Strasser has received funding through the Pfizer GRAND program, an independent peer‐reviewed grant program funded through Pfizer (2008‐2011); all investigators have received funding from the United States National Institutes of Health”
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Although participants were randomized to different brands of EC, no description on how randomization was carried out
Allocation concealment (selection bias)	Unclear risk	Not specified
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	No description of whether groups were blind to other conditions, but given similar levels of support between arms, so performance bias judged unlikely
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Unclear whether any blinding took place, some outcomes were measured using objective measures and there was no difference in contact between arms
Incomplete outcome data (attrition bias) All outcomes	High risk	For blu, Green Smoke, and V2 groups, 83% of participants completed the 10‐day study; only 33% of participants randomized to White Cloud completed the 10‐day study; meaning loss to follow‐up was considerably higher in this group
Selective reporting (reporting bias)	Low risk	All expected outcomes reported