What role do e-cigarettes play?
The use of electronic cigarettes or “vapes”—battery-operated devices that deliver nicotine to the user through vapor—has increased significantly since their US introduction in 2007. A recent study found that “ever use” of e-cigarettes increased from 1.8% in 2010 to 13% in 2013; current use increased from 0.3% to 6.8% in the same time frame.27 Vaping, as inhaling on an e-cigarette is sometimes known, causes a sensor to detect airflow and initiate the heating element to vaporize the liquid solution within the cartridge, which contains propylene glycol, flavoring, and nicotine.
There is limited evidence of the efficacy of e-cigarettes for smoking cessation, but there is support for their role in reducing the quantity of conventional cigarettes smoked. A 2014 Cochrane review of two RCTs evaluating e-cigarette efficacy for smoking cessation or reduction found evidence of increased abstinence at six months in users of e-cigarettes containing nicotine, compared with placebo e-cigarettes (9% vs 4%; RR, 2.29). Additionally, e-cigarette use was associated with a more than 50% decrease in cigarette smoking versus placebo (36% vs 27%; RR,1.31) or patch (61% vs 44%; RR, 1.41).28
A survey published after the review also showed a correlation between cigarette reduction (but not cessation) after one year of e-cigarette use.29 A subsequent RCT conducted in a controlled laboratory setting found that e-cigarettes were highly effective in reducing cessation-related cravings.30 And at eight-month follow-up, 44% of those using e-cigarettes were found to have at least a 50% reduction in the use of conventional cigarettes—and complete cessation in some cases.
Concerns about health effects
E-cigarettes have generally been thought to be safer than conventional cigarettes, given that they mainly deliver nicotine and propylene glycol instead of the more toxic chemicals—eg, benzene, carbon monoxide, and formaldehyde—released by conventional cigarettes.31 Carcinogens have also been found in e-cigarettes, but at significantly lower levels.31 However, a systematic review found wide variation in the toxin content of e-cigarettes.32 In addition, recent reports have detailed incidents in which e-cigarette devices were alleged to have exploded, causing severe bodily harm.33
Adverse effects of e-cigarettes include minor irritation of the throat, mouth, and lungs. Among cigarette-naive patients, lightheadedness, throat irritation, dizziness, and cough were most commonly reported. No serious adverse events have been reported, but the lack of long-term safety data is a source of concern.32
Additionally, minimal regulatory oversight of the e-cigarette industry exists. Currently, the FDA only has authority to regulate e-cigarettes that are marketed for therapeutic purposes, although the agency is seeking to extend its oversight to all e-cigarettes.
The bottom line: More data on safety and regulatory oversight are needed before recommendations on the use of e-cigarettes as a smoking cessation tool can be made.
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