Electronic cigarettes that contain nicotine are more effective than e-cigarettes without nicotine in helping smokers quit, and smokers attempting to quit are able to achieve a 50% or greater reduction in smoking with the use of e-cigarettes containing nicotine.
About 9% of smokers who used e-cigarettes that contained nicotine were able to stop smoking at up to 1 year, compared with about 4% of smokers who used nicotine-free e-cigarettes, according to a small-scale data review published in the Cochrane Database of Systematic Reviews (2014 Dec. 16:CD010216 [doi:10.1002/14651858.CD010216.pub2]).
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There is little clinical information on the amount of nicotine typically ingested from an e-cigarette.
“There is evidence from the pooled results of two trials that electronic cigarettes with nicotine, compared with [e-cigarettes without nicotine], helped smokers to stop smoking long-term; they also increased the number of people who did not quit altogether to halve cigarette consumption,” wrote Dr. Hayden McRobbie of the Wolfson Institute of Preventive Medicine, Queen Mary University of London, and his colleagues.
Of the smokers included in the review who were not able to quit conventional cigarettes, 36% who used e-cigarettes with nicotine reported reducing the number of conventional cigarettes consumed by about half, compared with 28% of users who were given e-cigarettes without nicotine.
A team of researchers from New Zealand and the United Kingdom reviewed data from two trials of 662 current smokers to evaluate the efficacy of e-cigarettes use for helping smokers achieve long-term abstinence.
E-cigarettes are electronic vaporizing devices that heat a liquid, usually consisting of propylene glycol and glycerol and often containing nicotine, into an aerosol for inhalation.
There is little clinical information on the amount of nicotine typically ingested from an e-cigarette, as the devices typically are not regulated by government health agencies. No serious adverse effects related to e-cigarette use were reported from either of the studies.
Although this is the first meta-analysis on e-cigarette use and the effects on smoking cessation, the authors said that more data are needed for it to become clinically useful.
“Given the variety of electronic cigarette products on the market and the product evolution, future studies need to select electronic cigarettes with good nicotine delivery that are representative of the best current standard in terms of reliability and user satisfaction,” Dr. McRobbie and his associates wrote.
In addition, data were limited by the small number of trials and the small sample of participants from the studies. Also, there were few biochemical data on the participants or the sensorimotor effects of using electronic cigarettes.
“Data are also needed on the proportions of smokers who successfully quit smoking with the help of [e-cigarettes] and who continue to use [e-cigarettes] long-term and the proportion who eventually become nicotine-free,” the authors concluded.
Dr. Hayden McRobbie has undertaken educational sessions sponsored by Pfizer and Johnson & Johnson. Dr. Chris Bullen and Dr. McRobbie were also investigators on a study of e-cigarettes from an e-cigarette manufacturer (Ruyan Group) funded by the University of Auckland (New Zealand). Dr. Peter Hajek has provided consultancy to GSK, Pfizer, and Johnson & Johnson.