Electronic cigarettes: fact and faction

There are a number of public health advocates who appear to consider electronic cigarettes (e-cigarettes) primarily as a threat to public health, and bodies such as the British Medical Association (BMA) and the World Health Organization (WHO) are warning smokers about their potential dangers.1 This editorial takes a close look at the evidence.

Published: 01 September 2014

Positive: Yes

Link to publication: http://bjgp.org/content/64/626/442

Authors:


Full text

WHAT ARE E-CIGARETTES?

E-cigarettes are devices designed to give much of the experience of smoking and usually contain a certain amount of nicotine without exposing the user to the highly carcinogenic tar and harmful carbon monoxide gas that cigarettes deliver.2 Many of them look broadly similar to cigarettes but are often larger and sport different colours; some look very different from cigarettes. Some have a tip that glows red, blue, or green when the user sucks on them. They contain a battery-powered heating element that is activated either manually or automatically when the user sucks on the end. This element heats a liquid mostly made up of propylene glycol or glycerol, usually with some nicotine and flavourings. The resulting vapour is inhaled and delivers varying amounts of nicotine, typically less than from smoking, depending on the device and experience of the user. Some of the vapour is exhaled as a visible mist.

Given that smokers smoke primarily for the nicotine but die primarily from the tar,3 one might imagine that e-cigarettes would be welcomed as a means to prevent much of the death and suffering caused by cigarettes. For every million smokers who switched to an e-cigarette we could expect a reduction of more than 6000 premature deaths in the UK each year, even in the event that e-cigarette use carries a significant risk of fatal diseases, and users were to continue to use them indefinitely.

SAFETY OF E-CIGARETTES

This raises the question as to why some in the public health community are so vociferous in their opposition to them. One concern is over safety. Given how long it took to discover the link between smoking and lung cancer when the risks were so great, we have to accept that it will probably be more than 30 years before we would have a chance of being able to use epidemiology to quantify risks from e-cigarette use. In fact we may never be able to do so because we are chasing a moving target in terms of the products and their development.

This means that we must make judgements based on the toxicology of the vapour. Despite alarmist commentaries, studies on the toxicology of the vapour tell us that, while propylene glycol is an irritant and some toxins are present in measurable quantities, the concentrations are in fact very low.4 Some reviews have bizarrely concluded that we do not know whether e-cigarette use is safer than smoking,5 ignoring the fact that the vapour contains nothing like the concentrations of carcinogens and toxins as cigarette smoke.6,7 In fact, toxin concentrations are almost all well below 1/20th that of cigarette smoke.

EFFECT OF E-CIGARETTES ON SMOKING PREVALENCE

The second concern is that widespread use of e-cigarettes may ‘re-normalise’ smoking, leading to an increase in smoking prevalence, or at least a slowing down of the rate of decline. Yet, in England, where the ‘Smoking Toolkit Study’ surveys the adult population every month, the rise in prevalence of e-cigarette use has been accompanied by an increase in smoking cessation rates and a continued fall in smoking prevalence.8,9 The proportion of those aged 16–25 years who have ever smoked regularly has stayed constant at 30% over the period when e-cigarette use has increased.8

E-CIGARETTES AND SMOKING CESSATION

The third concern is that there is only limited scientific evidence that e-cigarettes can help smokers to stop smoking. Two randomised controlled trials (RCTs) of now obsolete products that delivered little nicotine found those products to yield success rates broadly similar to licensed nicotine products.10,11 More trials of newer products are needed but these will only give us part of the answer. The number and variety of products, the rate of development, the time taken to conduct these trials, and the difficulty in generalising to people who are not willing to be randomised mean that we will have to supplement randomised trials with other kinds of study.

A review of surveys suggested that e-cigarette use by smokers might hinder quitting. However, the studies reviewed could not address the question satisfactorily because they failed to address differences in important factors such as nicotine dependence among those using e-cigarettes versus other smokers, and/or did not address whether the e-cigarettes were used as part of a quit attempt.6 A recent study has addressed these deficiencies.9 It used a survey methodology that had previously confirmed RCT findings that behavioural support and licensed nicotine products and varenicline obtained on prescription all improve smokers’ chances of stopping, while confirming findings from other studies that licensed nicotine products when bought over the counter may not improve the chances of stopping.12,13 The latest study, involving almost 6000 respondents, found that use of an e-cigarette in the most recent quit attempt was associated with a 60% increase in the odds of still being abstinent compared with using no aid and with using a licensed nicotine product bought over the counter.14 This difference persisted after adjusting statistically for a wide range of potential confounding variables. This is just one correlational study but it is an important piece of the jigsaw.

E-CIGARETTES AS A GATEWAY TO SMOKING

The fourth concern is that e-cigarettes may act as a gateway into smoking. The gateway hypothesis has been widely debated in relation to ‘soft’ and’ hard’ drugs and it has been recognised that simply counting the numbers of people who try a ‘soft’ drug and go on to use a ‘hard’ drug does not address the question.14 The reason is obvious: the association could easily be due to a pre-existing disposition on the part of the people concerned. To date, studies that have been claimed as addressing the gateway issue in relation to e-cigarettes have not in fact done so.1 Moreover, warnings about a rapid rise in e-cigarette use among the young have been based on the proportion of young people who report ever having tried an e-cigarette, not the proportion of current users.15 In England, the proportion of current users in people who have not smoked regularly remains extremely small at 0.2%.8

THE NEED FOR OBJECTIVITY

This brings us back to the question as to why some individuals and bodies involved in public health are so opposed to e-cigarettes. It may be a concern over how things might turn out in the future given commercial incentives, puritanical ethics, distaste for any industry profiting from a psychoactive drug, inappropriate application of a medical rather than a public health model, or even just a gut feeling that e-cigarettes are bad. Whatever the reasons, it is important that interpretation of the evidence and communication with policy makers and the public is not distorted by a priori judgements.16

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Nicotine Levels and Presence of Selected Tobacco-Derived Toxins in Tobacco Flavoured Electronic Cigarette Refill Liquids

Some electronic cigarette (EC) liquids of tobacco flavour contain extracts of cured tobacco leaves produced by a process of solvent extraction and steeping. These are commonly called Natural Extract of Tobacco (NET) liquids. The purpose of the study was to evaluate nicotine levels and the presence of tobacco-derived toxins in tobacco-flavoured conventional and NET liquids.

Published: 24 March 2015

Positive: Yes

Link to publication: http://www.mdpi.com/1660-4601/12/4/3439

Link to press release: http://www.ecigarette-research.org/research/index.php/research/research-2015/195-ecig-net

Authors

Konstantinos E. Farsalinos
I. Gene Gillman
Matt S. Melvin
Amelia R. Paolantonio
Wendy J. Gardow
Kathy E. Humphries
Sherri E. Brown
Konstantinos Poulas
Vassilis Voudris


Summary

Methods. Twenty-one samples (10 conventional and 11 NET liquids) were obtained from the US and Greek market. Nicotine levels were measured and compared with labelled values. The levels of tobacco-derived chemicals were compared with literature data on tobacco products.

Results. Twelve samples had nicotine levels within 10% of the labelled value. Inconsistency ranged from −21% to 22.1%, with no difference observed between conventional and NET liquids. Tobacco-specific nitrosamines (TSNAs) were present in all samples at ng/mL levels. Nitrates were present almost exclusively in NET liquids. Acetaldehyde was present predominantly in conventional liquids while formaldehyde was detected in almost all EC liquids at trace levels. Phenols were present in trace amounts, mostly in NET liquids. Total TSNAs and nitrate, which are derived from the tobacco plant, were present at levels 200–300 times lower in 1 mL of NET liquids compared to 1 gram of tobacco products.


 

Conclusions

NET liquids contained higher levels of phenols and nitrates, but lower levels of acetaldehyde compared to conventional EC liquids. The lower levels of tobacco-derived toxins found in NET liquids compared to tobacco products indicate that the extraction process used to make these products did not transfer a significant amount of toxins to the NET. Overall, all EC liquids contained far lower (by 2–3 orders of magnitude) levels of the tobacco-derived toxins compared to tobacco products.

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Electronic cigarette use and harm reversal: emerging evidence in the lung

Direct confirmation that long-term EC use leads to reductions in smoking-related diseases is not available and it will take a few decades before the tobacco harm reduction potential of this products is firmly established. Nonetheless, it is feasible to detect early changes in airway function and respiratory symptoms in smokers switching to e-vapor.

Published: 18 March 2015

Positive: Yes

Link to publication: http://www.biomedcentral.com/1741-7015/13/54

Authors:

Riccardo Polosa


Summary

Abstract

Electronic cigarettes (ECs) have been rapidly gaining ground on conventional cigarettes due to their efficiency in ceasing or reducing tobacco consumption, competitive prices, and the perception of them being a much less harmful smoking alternative. Direct confirmation that long-term EC use leads to reductions in smoking-related diseases is not available and it will take a few decades before the tobacco harm reduction potential of this products is firmly established. Nonetheless, it is feasible to detect early changes in airway function and respiratory symptoms in smokers switching to e-vapor. Acute investigations do not appear to support negative respiratory health outcomes in EC users and initial findings from long-term studies are supportive of a beneficial effect of EC use in relation to respiratory outcomes. The emerging evidence that EC use can reverse harm from tobacco smoking should be taken into consideration by regulatory authorities seeking to adopt proportional measures for the e-vapor category.

Keywords:

E-cigarette; E-vapor products; Harm reversal; Lung function; Respiratory system; Smoking cessation; Tobacco harm reduction

Background

The electronic cigarette (EC) has been rapidly gaining ground on conventional cigarettes and could surpass consumption of conventional cigarettes within the next decade, according to some prediction analyses [1]. The growing popularity of ECs proves that many adult smokers are keen on using an alternative technologic form of smoking to reduce cigarette consumption or quit smoking and to relieve tobacco withdrawal symptoms [2]. Data from internet surveys [2],[3] and clinical trials [4],[5] have shown that ECs may help smokers quit or reduce their tobacco consumption. Moreover, the popularity of ECs appears to be associated with the fact that they can be used in many smoke-free areas, their prices are competitive, and they are perceived as a much less harmful smoking alternative [3],[6].

Vapor toxicology under normal conditions of use is by far less problematic than that of conventional cigarettes [7], and exclusive EC users have significantly lower urine levels of tobacco smoke toxicants and carcinogens compared to cigarette smokers [8]. Thus, smokers completely switching to regular EC use are likely to gain significant health benefits.

Although a reduction in smoking-related diseases from long-term EC use can be inferred by the positive findings on Swedish snus (a tobacco harm reduction product consisting of refined oral tobacco which is low in nitrosamines) [9], direct confirmation is not available and it will take a few decades before a reduction in individual and population health outcomes due to the regular use of e-vapor products can be firmly established. Nonetheless, it is feasible to detect early changes in airway function and respiratory symptoms in smokers switching to e-vapor.

In this commentary, I discuss the emerging potential of ECs for harm reversal with a specific focus on the respiratory system.


Conclusion

Compared to combustible cigarettes, e-vapor products are at least 96% less harmful and may substantially reduce individual risk and population harm [22]. Future research will better define and further reduce residual risks from EC use to as low as possible by establishing appropriate quality control and standards. Although large longitudinal studies are warranted to elucidate whether ECs are a less harmful alternative to tobacco cigarettes and whether significant health benefits can be expected in smokers who switch from tobacco to ECs, the emerging evidence that EC use can reverse harm from tobacco smoking should be taken into consideration by regulatory authorities seeking to adopt proportional measures for the e-vapor category [23].

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Gateway effects: why the cited evidence does not support their existence for low-risk tobacco products (and what evidence would)

It is often claimed that low-risk drugs still create harm because of “gateway effects”, in which they cause the use of a high-risk alternative. Such claims are popular among opponents of tobacco harm reduction, claiming that low-risk tobacco products (e.g.,ecigarettes, smokeless tobacco) cause people to start smoking, sometimes backed by empirical studies that ostensibly support the claim. However, these studies consistently ignore the obvious alternative causal pathways, particularly that observed associations may represent causation in the opposite direction (smoking causes  people to seek low risk alternatives) or confounding (the same individual factors increase the chance of using any tobacco product).

Published: 9 March 2015

Positive: Yes

Link to publication: http://antithrlies.com/2015/03/12/new-phillips-working-paper-on-thr-related-gateway-claims/

Author:

Carl V. Philips (CASAA)


Summary

Abstract

It is often claimed that low-risk drugs still create harm because of “gateway effects”, in which they cause the use of a high-risk alternative. Such claims are popular among opponents of tobacco harm reduction, claiming that low-risk tobacco products (e.g., ecigarettes, smokeless tobacco) cause people to start smoking, sometimes backed by empirical studies that ostensibly support the claim. However, these studies consistently ignore the obvious alternative causal pathways, particularly that observed associations may represent causation in the opposite direction (smoking causes people to seek low risk alternatives) or confounding (the same individual factors increase the chance of using any tobacco product). Due to these complications, any useful analysis must to deal with simultaneity and confounding by common case. In practice, existing analyses provide almost cartoon examples of drawing naïve causal conclusions from observed associations. The present analysis examines what evidence and research strategies would be needed to empirically detect such a gateway effect, if there were one, explaining key methodological concepts including causation and confounding, examining the logic of the claim, identifying potentially useful data, and debunking common fallacies on both side of the argument, as well as presenting an extended example of proper empirical testing. The analysis demonstrates that none of the empirical studies to date that purport to show a gateway effect from tobacco harm reduction products actually does so. The observations and approaches can be generalized to other cases where observed association of individual characteristics in cross-sectional data can result from one or several causal relationships.


Conclusion

Searching for some signal of a gateway effect amidst overwhelming confounding requires more rigorous methods than are typical in public health epidemiology. This generalizes to any attempt to use cross-sectional data to sort out causation in a particular direction from confounding or reverse causation. When seeking epidemiologic associations where confounding is minimal or relatively simple in its causes, the typical methods used in the field are still far from optimal, but the empirical results might still be basically useful. That is not the case in this context. While it might never be possible to convincingly demonstrate a gateway effect given the challenges, and statistical analyses have no hope of detecting a tiny effect, there are clearly better and worse ways to pursue the question.

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Electronic cigarette use among patients with cancer: Characteristics of electronic cigarette users and their smoking cessation outcomes

Given that continued smoking after a cancer diagnosis increases the risk of adverse health outcomes, patients with cancer are strongly advised to quit. Despite a current lack of evidence regarding their safety and effectiveness as a cessation tool, electronic cigarettes (E-cigarettes) are becoming increasingly popular. To guide oncologists’ communication with their patients about E-cigarette use, this article provides what to the authors’ knowledge is the first published clinical data regarding E-cigarette use and cessation outcomes among patients with cancer.

Published: 22 September 2014

Positive: No

Link to publication: http://onlinelibrary.wiley.com/enhanced/doi/10.1002/cncr.28811/

Debunked by Carl Philips: http://antithrlies.com/2015/03/12/what-is-peer-review-really-part-8-the-case-of-borderud-et-al/

Authors:

Sarah P. Borderud
Yuelin Li
Jack E. Burkhalter
Christine E. Sheffer
Jamie S. Ostroff


Summary

METHODS

A total of 1074 participants included smokers (patients with cancer) who recently enrolled in a tobacco treatment program at a comprehensive cancer center. Standard demographic, tobacco use history, and follow-up cessation outcomes were assessed.

RESULTS

A 3-fold increase in E-cigarette use was observed from 2012 to 2013 (10.6% vs 38.5%). E-cigarette users were more nicotine dependent than nonusers, had more prior quit attempts, and were more likely to be diagnosed with thoracic and head or neck cancers. Using a complete case analysis, E-cigarette users were as likely to be smoking at the time of follow-up as nonusers (odds ratio, 1.0; 95% confidence interval, 0.5-1.7). Using an intention-to-treat analysis, E-cigarette users were twice as likely to be smoking at the time of follow-up as nonusers (odds ratio, 2.0; 95% confidence interval, 1.2-3.3).


Conclusions

The high rate of E-cigarette use observed is consistent with recent articles highlighting increased E-cigarette use in the general population. The current longitudinal findings raise doubts concerning the usefulness of E-cigarettes for facilitating smoking cessation among patients with cancer. Further research is needed to evaluate the safety and efficacy of E-cigarettes as a cessation treatment for patients with cancer. Cancer 2014;120:3527–3535. © 2014 American Cancer Society.

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Does the magnitude of reduction in cigarettes per day predict smoking cessation? A qualitative review

Reduction in cigarettes per day (CPD) aided by nicotine replacement therapy (NRT) increases cessation in smokers; however, it is unclear whether this is due to use of NRT or reduction per se. If the latter, a greater magnitude of reduction in CPD should increase the odds of cessation.

Results show that dual use increases tobacco cessation.

Published: 05 March 2015

Positive: Yes

Link to publication: http://ntr.oxfordjournals.org/content/early/2015/03/04/ntr.ntv058.short?rss=1

A good analysis from Dr Siegel: http://tobaccoanalysis.blogspot.fr/2015/03/new-study-provides-evidence-that.html

Article en Français sur l’étude: http://www.ma-cigarette.fr/etude-la-cigarette-electronique-aide-au-sevrage-tabagique-meme-pour-les-vapofumeurs/

Authors:

Elias M. Klemperer, B.A.
John R. Hughes, M.D.


Summary

Methods: The authors searched PubMed, Cochrane, PsychINFO, clinicaltrials.gov and their personal libraries for studies on smoking reduction. Seven of the 76 (9%) identified intervention trials and four of 28 naturalistic studies (14%) reported on the magnitude of reduction in relation to the odds of cessation.

Results: Five of the seven intervention trials and three of the four naturalistic observational (cohort) studies found that increased reduction in CPD was associated with increased cessation. The intervention trials that reported effect sizes found that every one percent decrease in CPD or carbon monoxide (CO) was associated with a 3% to 4% increase in the odds of cessation. The naturalistic studies found that ordinal (e.g., quartile) increases in participants’ magnitude of reduction in CPD were associated with 50% to 290% increases in the odds of cessation. All of the naturalistic studies and four of the intervention trials included covariates; however, reduction’s association with cessation could still be due to its association with NRT use or motivation.


Conclusions

Although prospective prediction does not necessarily indicate causality, our findings suggest reduction in CPD is a mechanism of increased cessation in prior NRT-aided reduction studies.

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