What are the risks?
Cancer
A handful of known carcinogens can be found in inhaled vapor, including formaldehyde, acetaldehyde, acrolein, toluene, and nitrosamines. However, they are present in far lower concentrations than in traditional cigarettes (Goniewicz ML, et al. JAMA Netw Open. 2018;1[8]e185937). This leads to the natural assumption that vaping, while not benign, poses a much lower cancer risk when compared with smoking. Whether that is borne out in the long term remains to be seen.
Pulmonary function
The long-term effect on pulmonary function is not known. Small studies have shown no significant changes to spirometry after acute exposure to vapor. More data are needed in this area (Palazzolo DL. Frontiers Public Health. 2013;1[56]1-20).
Wound healing
An animal study has shown evidence of poor wound healing extrapolated from skin flap necrosis in rats. Exposure to vapor vs smoke yielded similar results, and both were worse than the sham arm (Troiano C, et al. JAMA Facial Plast Surg. 2019;21[1]:5). While it is difficult to know how to apply this clinically, it may be prudent to advise patients to abstain while in preparation for elective surgery.
Cardiovascular/stroke
Much of the cardiovascular toxicity from cigarette use is tied to the myriad of complex toxic particles produced in inhaled smoke, the vast majority of which are not present in e-cigarette vapor. While nicotine itself has known acute cardiovascular effects, including tachycardia and vasoconstriction, a tolerance to these effects occurs over time. Previous evaluations of nicotine replacement therapies and smokeless tobacco for their cardiovascular effects have had mixed results. But, there appears to be a trend toward minimal cardiovascular risk when using “cleaner” products, such as nicotine replacement therapy compared with smokeless tobacco (Benowitz NL, et al. Nature Rev Cardiol. 2017;14[8]:447). Whether this can be extrapolated to electronic cigarette use is unknown but is encouraging.
Alternative toxicity
In addition to the above risks that are in comparison to traditional smoking, vaping also introduces novel toxicities. There are case reports of lipoid pneumonia, ARDS, hypersensitivity pneumonitis, eosinophilic pneumonia, and diffuse alveola hemorrhage. Burns from malfunctioning devices must also be considered, as there is a wide array of products available, at differing levels of build quality.
Toxic oral ingestion of nicotine, especially by children, has led to increased calls to poison centers. For a small child, this can be fatal. Regulation of labels and containers could curtail this issue. But, public education regarding the toxicity of these substances when ingested in large quantities is also important. If there is a lack of understanding about this danger, then typical safeguards are easily overlooked by individual users.
Are there benefits?
Smoking cessation
Compared with other products, such as nicotine patches, gum, and pharmaceutical methods, e-cigarettes most closely mimic the actual experience of smoking. For some, the habit and ritual of smoking is as much a part of the addiction as nicotine. Vaping has the potential to help alleviate this difficult aspect of cessation. Data involving early generation products failed to show a significant advantage. Newer devices that are more pleasurable to use and offer more efficient nicotine delivery may be more effective. Indeed, a recent study in the New England Journal of Medicine from this year demonstrated improved smoking cessation compared with traditional methods, using second generation vape devices (Hajek P, et al. N Engl J Med. 2019;380[7]629). It will be interesting to see if this can be repeatable going forward and if protocols can be established to maximize effectiveness.
Dr. Jason Clark
As outlined above, it is difficult to make definitive conclusions or recommendations regarding electronic cigarette use at the present time. The risk of cancer and cardiopulmonary disease is likely to be significantly lower but not eliminated. Use as a smoking cessation aid is starting to show promise. Even without cessation, ongoing vaping is likely to be safer than ongoing smoking. Two caveats to this remain: some patients, in an effort to quit smoking, may take up vaping but eventually become “dual users.” This scenario has been associated with higher toxic exposure and possibly worse outcomes. The second caveat is that while there is promise to using this as a cessation tool, it should not yet replace other more well-studied, first-line agents in this regard. It should, perhaps, target patients who are motivated to quit but have failed more traditional methods. Finally, there continues to be concern that vaping could appeal to never smokers, given its perceived safety profile and ease of use in public places. This could lead to an overall increase in nicotine addiction, which could be a significant step backwards.
Dr. Clark is Assistant Professor, Pulmonary and Critical Care Medicine, UT Southwestern Medical Center, Dallas, Texas.