Abstract
Nicotine cessation medication, combined with behavioral support, is considered the “gold standard” treatment for tobacco cessation, but it is only successful in 20% to 30% of patients. New and alternate tobacco cessation strategies are needed to address patients who fail or are unwilling to use current evidence-based options for cessation. Electronic cigarettes are one such product gaining popularity for use as a smoking cessation aid. Robust evidence-based support of e-cigarettes for smoking cessation is lacking, but their use is likely less harmful than that of conventional cigarettes. As such, it is reasonable to support a quit attempt with e-cigarettes following failure of evidence-based cessation treatments and behavioral support, stressing the fact that it is safest to do so without continuing to smoke tobacco.
‘Electronic cigarettes, or e-cigarettes, are one such product gaining popularity for use in smoking cessation.’
Nicotine cessation medication, combined with behavioral support, is considered the “gold standard” treatment for tobacco cessation, but it is only successful in 20% to 30% of patients willing to make a quit attempt. 1 New and alternate tobacco cessation strategies are of great importance to address the 60% to 80% of patients who fail or are unwilling to use current evidence-based options for cessation. Electronic cigarettes, or e-cigarettes, are one such product gaining popularity for use in smoking cessation. As the awareness and use of e-cigarettes increases, it is important for clinicians to be familiar with the risks and benefits of their use to provide patients the most accurate information and counseling. Data regarding the safety and efficacy of e-cigarettes for smoking cessation will be discussed below.
Electronic Cigarettes
Electronic cigarettes were developed in China and first introduced in the United States in 2007. The products available vary widely but are designed to mimic cigarettes without combustion of tobacco. Instead, e-cigarettes aerosolize a solution generally consisting of nicotine, flavorings, propylene glycol, and/or glycerol. Unlike traditional cigarettes, the exhaled aerosol from e-cigarettes does not contain tar, smoke, or carbon monoxide. Proponents of e-cigarettes suggest that the aerosolized form of nicotine reduces the deleterious health effects traditional cigarettes impose and promote it as a less harmful alternative to tobacco smoking. E-cigarettes may reduce the tobacco-related harm of combustible cigarettes by assisting in the complete cessation of smoking, reducing the number of traditional cigarettes smoked, and reducing secondhand smoke exposure. However, these benefits have yet to be fully substantiated by evidence-based research.
Electronic cigarettes are rapidly changing the tobacco control landscape. Awareness of e-cigarettes rose from 16% in 2009 to nearly 80% in 2013.2,3 Likewise, e-cigarette use has increased dramatically. Depending on sampling methods, prevalence of e-cigarette use is up from 3% in 2010 to 20% to 30% in 2012.4,5 North American surveys indicate that most e-cigarette users are current or former smokers and that many e-cigarette users intend to use the products to cease or substantially reduce their smoking.6,7 Currently, e-cigarettes are not regulated by the US Food and Drug Administration. Lack of regulation may result in inaccurate or inadequate labeling, marketing, and manufacturing. As such, clinicians need to be familiar with evidence related to e-cigarettes to correct false perceptions and provide sound counseling to patients considering their use as a smoking cessation aid.
Cessation Aid Data
To date, there are only 2 randomized controlled trials and 1 well-designed cross-sectional survey assessing the efficacy of e-cigarettes for smoking cessation. The first randomized controlled trial compared the use of e-cigarettes with and without nicotine to nicotine patches in 657 healthy New Zealanders, all interested in quitting smoking. 8 Subjects were assigned to 1 of 3 interventional groups: group 1 received 16 mg nicotine e-cigarettes, group 2 received 21 mg nicotine patches, and group 3 received placebo e-cigarettes. At 6 months, smoking cessation rates were assessed, and no statistically significant difference was observed between groups. Cessation rates were 7.3% in the nicotine e-cigarette group, 5.8% in the nicotine patch group, and 4.1% in the placebo e-cigarette group. The authors concluded that e-cigarettes are modestly effective at helping smokers quit, similar to use of nicotine patches without behavioral support. Interestingly, the study also found that dual use of conventional cigarettes and cessation aid persisted at 6 months, though at much lower rates in the nicotine patch group (29% for e-cigarette users vs 7% for patch users). 8
The second randomized controlled trial assessed e-cigarette use in healthy Italian smokers, uninterested in quitting at baseline. 9 The subjects were randomized to 12 weeks of 1 of 3 regimens: group 1 received 7.2 mg nicotine cartridges for 12 weeks, group 2 received 7.2 mg nicotine cartridges for 6 weeks followed by 5.4 mg nicotine cartridges for 6 weeks, and group 3 received placebo nicotine cartridges for 12 weeks. After 12 months, subjects were assessed for reduction in cigarette smoking and smoking cessation rates. The researchers found no difference in quit rate between the 3 groups with a mean cessation rate of 9%. Reduction in smoking was seen in 10.3% of subjects at 12 months, with similar reductions in number of conventional cigarettes smoked across groups.
Last, a well-designed, large, cross-sectional survey of adult smokers assessed the use of e-cigarettes for smoking cessation under “real-world” conditions. The survey found that e-cigarette users were 63% more likely to achieve successful smoking cessation compared with those who used nicotine replacement therapy and 61% more likely to achieve successful cessation compared with those who had no support quitting. 10 Importantly, these interventions occurred in subjects who wanted to quit smoking without professional help. All products were purchased over the counter without the oversight of a health care professional or any behavioral support.
Safety Data
While preliminary evidence exists that e-cigarettes may be helpful in controlling or ceasing tobacco use, the safety and health effects of e-cigarettes is a major public health concern. The sheer number of types and designs of electronic cigarettes complicate the ability to assess for product safety, and in general, the health effects of e-cigarettes have not been well studied. Much of the deleterious health effects of conventional cigarette smoking is caused by the tobacco combustion products. 11 While minor tobacco alkaloids and tobacco-specific nitrosamines have been detected in some (but not all) e-cigarette products, the levels are low and unlikely to cause significant carcinogenic risk. 12
Other potentially dangerous components found in e-cigarettes include propylene glycol and metals. Propylene glycol is generally considered nontoxic; however, it can cause ocular and respiratory irritation and some concern exists over inhalation of the compound in patients with asthma or chronic obstructive pulmonary disease. Limited data exist to substantiate these concerns. Low levels of potentially harmful metals have also been detected in several available e-cigarette products. 13 These metals include tin, silver, iron, nickel, cadmium, and copper. While the metals are found in low levels, caution is warranted as the effects of prolonged exposure to these elements is unknown.
Both electronic and conventional cigarettes contain nicotine. Electronic-cigarettes are generally marketed as high, medium, or low strength with nicotine concentrations ranging between 6 and 36 mg/mL. In comparison, one combustible cigarette contains approximately 10 to 15 mg of nicotine. While the predominant health concern with nicotine lies in its addictive properties, the chemical can also increase heart rate and blood pressure, constrict coronary arteries, promote insulin resistance, and endothelial dysfunction and adversely effect lipid levels. 11 There is little data regarding the long-term effects of prolonged exposure to nicotine, though the available data (from long-term nicotine replacement therapy in former smokers) found no adverse effects for use up to several years. 14 While there are currently no studies assessing the effects of e-cigarettes in patients with existing cardiovascular disease, the risks of nicotine replacement are small compared with continued tobacco smoking. 15
Conclusions and Recommendations
The use of electronic cigarettes as a smoking cessation aid has provoked much debate among clinicians and raised several public health concerns. As discussed above, robust evidence-based support of e-cigarettes for smoking cessation is lacking, but the use of electronic cigarettes is likely less harmful than that of conventional cigarettes. The American Heart Association (AHA) recently published a policy statement regarding the use of electronic cigarettes. 7 The AHA recommends e-cigarette use should be included in tobacco screening questions during the patient interview and that clinicians should be educated about the benefits and risks of their use. While there is not enough evidence to encourage patients to use e-cigarettes as the primary means for smoking cessation, it is reasonable to support a quit attempt with e-cigarettes following failure of evidence-based cessation treatments and behavioral support. Patients who do choose to use e-cigarettes should be advised that it is safest to do so without continuing to smoke tobacco, because even at reduced levels, conventional cigarettes impose tobacco-induced health risks.