A systematic review of randomized controlled trials and network meta-analysis of e-cigarettes for smoking cessation

•Participants randomised to receive nicotine e-cigarettes were 49% more likely to remain abstinent from smoking than those who received NRTs.•Those randomised to receive nicotine e-cigarettes were 109% more likely to remain abstinent from smoking than those in control conditions where no nicotine was supplied.•However, most of the trials have moderate or high level of bias.•More high-quality studies are required to ascertain the effect of e-cigarette on quitting.