Polosa 2011.

Study characteristics
Methods	Design: Prospective cohort Recruitment: Advertisments in local hospital in Catania, Italy Setting: not specified Study start date: February 2010; Study end date: June 2010
Participants	Total N: 40, hospital staff Inclusion criteria: Healthy people who smoke 18 ‐ 60 years old smoking ≥ 15 cpd for at least the past 10 years, and not wanting to quit smoking at any time in the next 30 days Exclusion criteria: History of alcohol and illicit drug use Psychiatric illness Recent myocardial infarction Angina pectoris High blood pressure (BP > 140 mmHg systolic or 90 mmHg diastolic, or both) Diabetes mellitus Severe allergies Poorly‐controlled asthma or other airways diseases 35% women, mean age 42.9 (SD 8.8), median cpd 25 (IQR 20 ‐ 30), median FTND 6.0 (IQR 6 ‐ 8) Motivated to quit: No E‐cigarette use at baseline: Not specified
Interventions	EC: Cig‐a‐like Seen at baseline, given EC ('Categoria' brand) with an initial 4‐week supply of 7.4 mg nicotine cartridges. Instructed to use ad libitum up to 4 cartridges per day. EC cartridges supplied at months 1, 2, and 3 No instruction on cessation or reduction was provided
Outcomes	Follow‐up at 1, 2, 3, 6, 18 and 24 months where cigarette consumption, CO, and AEs were measured, incl. 30‐day PP CO‐validated abstinence at 6 months and CO‐validated abstinence at 18 and 24 months (not otherwise defined) Adverse events
Study funding	"We wish to thank Arbi Group Srl (Milano, Italy) for the free supplies of ‘Categoria’ e‐Cigarette kits and nicotine cartridges as well as their support. We would also like to thank the study participants for all their time and effort and LIAF (Lega Italiana AntiFumo) for the collaboration"
Author declarations	"None of the authors have any competing interests to declare, but RP has received lecture fees from Pfizer and, from Feb 2011, he has been serving as a consultant for Arbi Group Srl.Arbi Group Srl (Milano, Italy), the manufacturer of the e‐Cigarette supplied the product, and unrestricted technical and customer support. They were not involved in the study design, running of the study or analysis and presentation of the data"
Notes	Smoking cessation services provided to those who spontaneously asked for assistance with quitting. These participants were excluded from the study protocol
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Prospective cohort
Allocation concealment (selection bias)	High risk	Not randomized
Incomplete outcome data (attrition bias) All outcomes	Low risk	13/40 were lost to follow‐up, but used ITT analysis
Selective reporting (reporting bias)	Unclear risk	Unable to determine prespecified outcomes