Electronic Cigarettes (E-Cigs)

Views of Aficionados and Clinical/Public Health Perspectives

J. Foulds; S. Veldheer; A. Berg

Disclosures

Int J Clin Pract. 2011;65(10):1037-1042. 

In This Article

Discussion

The results of this face-to-face survey of experienced e-cig users are broadly consistent with previous online or e-mail based surveys of e-cig users in finding that a high proportion have completely replaced cigarette smoking with e-cig use.[5–8] Etter and Bullen[8] found that the cigarette-shaped models that had been tested in previous studies were seldom used by respondents in their large online survey. Among 3037 ever-users of e-cigs, 77% used e-cigs to quit smoking or avoid relapsing and 20% stated that they used e-cigs to reduce tobacco consumption with no intention of quitting smoking. Most of the ex-smokers in that study (79%) feared that they might relapse to smoking if they stopped using the e-cig.

The present study differed from prior e-cig studies by focusing on experienced long-term users, with the majority having used e-cigs for over a year. It also differs from prior studies in that the survey was completed in person rather than online (avoiding potential repeat completion by motivated activists). One interesting finding was that comparatively few of these e-cig aficionados are using the most widely marketed and sold types of e-cigs. Instead, they frequently use e-cigs with characteristics that appear designed to enable the atomiser to achieve a higher and more consistent temperature, resulting in a hotter, more intense vapour. This can be done in a number of ways, including (i) using more powerful (often larger) batteries, (ii) using batteries that last longer (and so produce consistent high heat for each use throughout the day), (iii) using a manual switch to initiate the atomiser prior to inhalation and enable a longer inhalation if necessary (pneumatic/airflow activation may result in the inhalation taking place before the atomiser had achieved a sufficient temperature).

It is possible, but remains to be confirmed by future studies, that these differences in characteristics of various e-cigs may at least partially explain the differences in nicotine absorption found in the initial studies.[4] These differences may also relate to user experience with the products. For example, some users of standard cigarette-shaped e-cigs with 3.7 v batteries learn to 'prime' (or preheat) the atomiser prior to inhalation by taking a priming puff a few seconds prior to the puff they intend to inhale.

Public Health Perspective

As e-cigs are largely sold via the internet, it is difficult to estimate total sales and use rates. However, in a legal case against the U.S. FDA, Smoking Everywhere, reported selling 600,000 e-cigs in just over a year, and NJOY reported selling 135,000 in the United States.[9] In a prospective survey by Siegel et al.,[5] the initial sampling frame was reported as consisting of purchasers of a new e-cig from one company (BLU) over a 2-week period and consisted of 5000 new customers. An unpublished study in the U.K. found that 9% of smokers had used e-cigs and 3% were still using them.[10] These figures, combined with the evidence of growing public interest in e-cigs based on internet searches, suggest that they could potentially have a public health impact. Clinicians will more frequently see patients who are e-cig users and will have to assess the potential impact on the individual patient's health. One inquest into the death of an e-cig user in the United Kingdom has already been widely reported.[11]

As in previous studies, most of the participants in this study used e-cigs as a way to quit smoking and because they perceive it to be much less harmful to their health than smoking. So the key questions are whether these products really help smokers to quit, and relative to both tobacco use, and existing smoking cessation medicines, whether the e-cigs themselves have their own health risks.

To date there are no published randomised clinical trials designed to test the efficacy and safety of e-cigs as smoking cessation aids. The few published short-term laboratory studies confirm that users do not absorb carbon-monoxide (confirming that no smoke is produced), but also suggest relatively low nicotine absorption, at least in inexperienced e-cig users, using standard e-cig models. Trtchounian and Talbot[12] evaluated the design and labelling of five popular e-cig brands and noted that leaking of liquid and inadequate labelling were common. For example, the labelling of liquid/cartridges does not specify whether the stated mg of nicotine is per cartridge or per millilitre. They concluded that regulation of manufacturing, quality control, sales and advertisements of e-cigs is needed.

In May 2009, the U.S. FDA announced the results of analyses of two leading brands of e-cigs and comparison with the FDA-approved Nicotrol Nicotine Inhaler.[13] They found that concentrations of nicotine were approximately proportional to the labelling (zero, low, medium and high), with some inconsistencies, and that a 100 ml puff on a 'medium' nicotine e-cig contained a similar amount of nicotine as a puff on the Nicotrol inhaler. The analyses also detected the presence of some impurities in the e-cig liquid, (e.g. tobacco specific nitrosamines and diethylene glycol), albeit at low levels. At that time, the FDA expressed concern about quality control and labelling accuracy of e-cigs. Following a court ruling, in April 2011, the FDA announced that it will not attempt to regulate e-cigs as drugs/devices (unless manufacturers make health claims or seek approval via that route), but rather will develop a strategy to regulate them as tobacco products.

Other studies have detected additional impurities in e-cig liquid or vapour, (e.g. polycyclic hydrocarbons, aldehydes, acrolein and glycerol), although generally at much lower concentrations than are found in cigarettes and on occasions e-cigs have been advertised as containing other drugs (e.g. tadalifil and rimonabant).[14,15] Propylene glycol (the primary vehicle in e-cig liquid) is generally considered safe in food. It is sometimes used as the vehicle in both inhaled and injected medicines (e.g. cyclosporine and lorazepam).[16,17]

Additional public health concerns include: (i) never-tobacco users may initiate nicotine use with e-cigs, (ii) e-cigs may be used mainly in places where smoking is banned and so help smokers continue their nicotine addiction by becoming a dual user, (iii) e-cigs may pose unknown health problems, such as via long-term inhalation of propylene glycol or inadvertent poisoning of a child consuming flavoured e-cig liquid (iv) e-cigs are unproven as smoking cessation aids and may be used in place of medicines that have been proven to be safe and effective for smoking cessation.[18]

There is clearly an urgent need for research to establish the safety profile of e-cigs and if this is demonstrated to be acceptable, to assess their efficacy as smoking cessation aids in appropriately designed clinical trials.[15]

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