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

Abstract and Introduction

Abstract

Background: Electronic cigarettes (e-cigs) have experienced a rapid growth in popularity but little is known about how they are used.
Aim: The aim of this study was to identify the e-cig products used by experienced e-cig users, their pattern of e-cig use and the impact on tobacco use.
Method: Face-to-face survey of 104 experienced e-cig users.
Results: Of all the e-cig users, 78% had not used any tobacco in the prior 30 days. They had previously smoked an average of 25 cigarettes per day, and had tried to quit smoking an average of nine times before they started using e-cigs. Two-thirds had previously tried to quit smoking using an FDA-approved smoking cessation medication. The majority of the sample had used e-cigs daily for at least a year. Three quarters started using e-cigs with the intention of quitting smoking and almost all felt that the e-cig had helped them to succeed in quitting smoking. Two-thirds used e-cig liquid with a medium to high concentration of nicotine (13 mg +). Only 8% were using the most widely sold types of cigarette-sized e-cigs that are typically powered by a single 3.7 volt battery. Instead most used e-cigs designed to enable the atomizer to more consistently achieve a hotter more intense vapour.
Conclusion: Until we have more evidence on the safety and efficacy of e-cigs for smoking cessation, smokers should be advised to use proven treatments (e.g. counselling and FDA-approved medicines). However, for those who have successfully switched to e-cigs, the priority should be staying off cigarettes, rather than quitting e-cigs.

Introduction

Electronic cigarettes (e-cigs) in the current form were invented by Chinese pharmacist Hon Lik in 2003 with patents held by the Ruyan company. Exports of e-cigs from China continue to rise despite legal challenges regarding their regulatory status (tobacco product, medical drug delivery device, or neither) and sales (mainly online) have continued to grow. One recent study reported that by September 2010 internet searches for e-cigs were several-hundred-fold greater than searches for nicotine replacement therapy products.[1] However, despite the rapid rise in popularity of these products, remarkably little is known about e-cigs, how they are used, what substances are in them and what substances are delivered to the user and the environment.

Figure 1 shows a typical e-cig setup for a breath-activated (pneumatic) inhalation. The cartridge holds a liquid mixture typically containing propylene glycol and nicotine. Inhalation activates a pressure-sensitive circuit that heats the atomizer and turns the liquid into a vapour which is drawn through the mouthpiece. The vapour is a fine mist without smoke or carbon-monoxide, which dissipates more quickly than smoke. Many e-cigs are designed for the tip of the e-cig to light up during inhalation and more recently some have been designed to light up blue rather than red to show that this is not really a cigarette (Figure 1).

Figure 1.

Typical components of an electronic cigarette

Two published studies have measured the blood nicotine levels resulting from e-cig use and, contrary to expectations, both studies found that even e-cigs labelled as 'high nicotine', produced remarkably low nicotine absorption. Bullen et al.[2] found that whereas smokers obtained a fairly typical blood nicotine concentration of 13.4 ng/ml from smoking a single cigarette, they obtained only 1.3 ng/ml from use of a Ruyan V8 e-cig, using a cartridge labelled as containing 16 mg of nicotine. Despite the very low nicotine delivery, the participants reported that the 'high nicotine' e-cig resulted in less desire to smoke than an e-cig containing a zero nicotine cartridge and was rated as more pleasant to use than the pharmaceutical nicotine inhaler (Johnson & Johnson Inc., New Brunswick, NJ, USA). Vansickel et al.[3] found that whereas smoking two regular cigarettes resulted in a peak blood nicotine increase from 2.1 ng/ml to 18.8 ng/ml, two 5-min puffing sessions with either the NPRO (NJOY, Scottsdale, AZ, USA) or HYDRO (Crown Seven, Scottsdale, AZ, USA) e-cigs loaded with 16–18 mg nicotine cartridges, resulted in very low blood nicotine levels (3.5 ng/ml and 2.5 ng/ml respectively). In contrast to cigarette smoking, 'vaping' an e-cig produced no increase in exhaled carbon-monoxide levels. It should be noted that both of these studies involved providing e-cig naïve cigarette smokers with e-cigs of the researchers' choosing and asking volunteers to use it, like a cigarette. However, more recently Vansickel et al.[4] reported (as yet unpublished) preliminary results from a study in which experienced e-cig users were allowed to use their own (customised) e-cigs. In this study, two of three initial participants achieved rapid increases in blood nicotine concentration with a similar order of magnitude and speed as a cigarette (> 10 ng/ml in 5 min).

These early signs of different results in experienced e-cig users (when compared with e-cig naïve smokers) suggest that we may learn useful information about e-cigs from these individuals, including a better understanding of the characteristics of the e-cigs they choose and their patterns of use. This paper reports on results of a face-to-face survey study of experienced e-cig users attending a meeting for e-cig aficionados, describes the e-cig products they use and discusses public health issues raised by these products and implications for clinicians.

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