A new Cochrane Review analysis provided an independent, rigorous assessment of the best available evidence to date about electronic cigarettes for quitting smoking and found that electronic cigarettes may help smokers stop their smoking, and there are no serious side effects associated with their use for up to two years.

The first Cochrane Review, published in the Cochrane Library in December 2014, also found that electronic cigarettes may be an aid to smokers in stopping their smoking. There haven't been any new randomized controlled trials (RCTs) with long-term outcomes looking at the effectiveness of electronic cigarettes in helping people to stop smoking, likely because the world leader in science, the United States, has put a de facto ban on the products by declaring anything made after 2007 must undergo FDA registration. The U.S. Centers for Disease Control and Prevention also conflates them with cigarettes, despite the fact that there is no smoke, and in the current politicization of science climate of the Obama administration, studies won't get funded if the hypothesis is anything else. 

Any smoking cessation or harm reduction tool is good. Smoking is a significant global health problem and, as the American Council on Science and Health has always phrased it, a pediatric disease. Once addicted to cigarettes, quitting is difficult, so if teens are going to do something for rebellion, an e-cigarette is much healthier than a cigarette.

No strategy works for all people, but nicotine patches and chewing gum, which deliver nicotine without the carcinogenic smoke, are valuable tools. For that reason, it is believed that e-cigarettes, which have gained in popularity among smokers, could be a valuable tool as well, though they are forbidden by law to be marketed as smoking cessation tools. They help to recreate similar sensations of smoking without exposing users or others to the smoke from conventional cigarettes. Since they can't be marketed for smoking cessation, little is still known about how effective they are at helping people stop smoking.

The original Review included two randomized clinical trials involving more than 600 participants, and found that electronic cigarettes containing nicotine may increase the chances of stopping smoking within six to 12 months, compared to using an electronic cigarette without nicotine. The researchers could not determine whether using electronic cigarettes was better than a nicotine patch in helping people stop smoking, because there were not enough people taking part in the study.

This updated Review now includes observational data from an additional 11 studies.  Of the studies which measured side effects, none found any serious side effects of using electronic cigarettes for up to two years. The studies showed that throat and mouth irritation are the most commonly reported side effects in the short-to medium-term (up to two years).

The lead author of this Cochrane Review, Jamie Hartmann-Boyce from the Cochrane Tobacco Addiction Group, said, “The randomized evidence on smoking cessation is unchanged since the last version of the Review. We are encouraged to find many studies are now underway, particularly as electronic cigarettes are an evolving technology. Since the last version of the Review, 11 new observational and uncontrolled studies have been published. In terms of quitting, these can’t provide the same information we get from randomized controlled trials, but they contribute further information on the side effects of using electronic cigarettes to quit smoking. None detected any serious side effects, but longer term data are needed.”

Citation: Hartmann-Boyce J, McRobbie H, Bullen C, Begh R, Stead LF, Hajek P. Electronic cigarettes for smoking cessation. Cochrane Database of Systematic Reviews 2016, Issue 9. Art. No.: CD010216. DOI: 10.1002/14651858.CD010216.pub3.