Electronic cigarettes can help people cut down or quit smoking without causing harm, according to a Cochrane review of ‘emerging evidence’.
Authors of the review say the results give some ‘early insights’ into the use of e-cigarettes for smoking cessation, but warn it is too early to draw firm conclusions because so few trials have been carried out.
However, they also note that newer e-cigarettes that have become available since these early trials may prove even more effective because they deliver more nicotine.
The team, from the UK and New Zealand, found two randomised trials of e-cigarettes, in 662 current smokers, and also 11 observational trials of e-cigarette use.
They found smokers using e-cigarettes had twice the quit rate of those using nicotine-free placebo versions, with 9% of e-cigarette users compared with 4% of the placebo group stopping smoking at up to a year of follow-up.
In addition, significantly more of the e-cigarette users were able to halve the number of conventional cigarettes they smoked – 36% of this group reduced the number of tobacoo cigarettes smoked by 50%, compared with 28% of the placebo users.
Only one of the trials compared e-cigarettes with nicotine patches, and this found the treatments had roughly similar efficacy.
Overall, there were no serious adverse effects from e-cigarette use in the studies.
Author Professor Peter Hajek, from Queen Mary University of London, said: ‘Although our confidence in the effects of electronic cigarettes as smoking cessation interventions is limited because of the small number of trials, the results are encouraging.
‘Both trials used electronic cigarettes with low nicotine delivery and it is likely that more recent products are more effective as previous research suggests that higher and faster nicotine delivery facilitates treatment effects. Several ongoing sutdies will help to answer the question more fully.’
NICE does not currently recommend GPs prescribe e-cigarettes for tobacco harm reduction, because none is licensed as a medicine, although that may change in future after the UK drugs regulator ruled some will be licensed.
Currently NICE says that GPs can advise patients e-cigarettes are probably less harmful than conventional cigarettes.