Published: 20 March 2014

Electronic cigarettes have become a staple of everyday UK life in a remarkably short time, but questions about their safety, efficacy and legal status still need to be answered. Dr Ilze Bogdanovica, Professor Linda Bauld and Professor John Britton from the UK Centre for Tobacco and Alcohol Studies review the facts and give their views.

Electronic cigarettes – commonly known as e-cigarettes – are novel nicotine delivery devices that were developed in China more than 10 years ago. Most first-generation devices bore a physical resemblance to cigarettes (so-called cigalikes), but a wide range of larger designs known by various names including personal vapourisers and clearomisers has since been introduced.

E-cigarettes have been available in the UK since around 2005, and since then sales and use have risen dramatically. This rapid proliferation in the UK and elsewhere has provoked extensive debate on the role of e-cigarettes in health and society. Although some claim that uncertainty about their effects and role in tobacco control precludes e-cigarettes from being endorsed on health grounds, others argue that any products that offer a significantly lower hazard alternative to tobacco should be welcomed. 

Potential benefits 

According to data from the Smoking Toolkit Study, the proportion of smokers in England who have used an e-cigarette in the past three months increased from around 2% in May 2011 to more than 15% in November 2013 – equivalent to around 1.3 million smokers in the UK. Use does not seem to vary by sex or socioeconomic status. Use among non-smokers in the UK, and particularly among young non-smokers, is rare. Although data for prevalence suggest that growth stalled in late 2013, some people have forecast that use of these products will soon overtake that of cigarettes.

Most smokers who use e-cigarettes do so to help them to cut down or stop smoking, though some report use predominantly to replace cigarettes at times when smoking is not allowed or accepted. Smokers smoke for nicotine, but are killed by the carcinogens, carbon monoxide and many other toxins that accompany nicotine in tobacco smoke. Because e-cigarettes deliver nicotine in vapour rather than smoke, their emissions are limited to those contained in, or generated from, the nicotine solution used in the device. 

Although data for e-cigarette emissions are sparse, those available suggest that nicotine, propylene glycol, glycerine, flavours (sometimes) and a range of contaminants or products of the heating process, including tobacco-specific nitrosamines, carbonyls, volatile organic compounds and metals, are present in the vapours. Although less pure than the vapour produced by a medicinal nicotine inhaler product (such as the Nicorette Inhalator), e-cigarette emissions are much less hazardous than tobacco smoke. 

The main benefit of e-cigarettes, therefore, is that they provide inhalable nicotine in a formulation that mimics the behavioural components of smoking but has relatively little risk. And for the smoker who cannot quit, or wants to continue to use nicotine in a manner that resembles smoking, e-cigarettes are an obvious choice. Switching completely from tobacco to e-cigarettes achieves much the same in health terms as does quitting smoking and all nicotine use completely. Furhtermore, e-cigarettes tend to be cheaper than is tobacco smoking, and risks associated with passive exposure to e-cigarette vapour are far less than those associated with passive exposure to tobacco smoke. 

Potential hazards 

The potential hazards of e-cigarettes fall into three broad categories: those from the product itself, those arising from the relationship between use and tobacco smoking, and those from the exploitation of e-cigarettes to promote tobacco smoking. 

Given the likely low hazard of inhaled nicotine, potential risks to health from the product arise almost entirely from the other constituents of vapour. The main component is propylene glycol, which is thought to be safe, although adverse lung effects from sustained long-term inhalation cannot be ruled out. Similar concerns apply to other constituents, but again the risks are probably slight. Thus, even in the absence of regulation to ensure product standards, the direct hazard to users – irrespective of smoking status – and others, from e-cigarettes is low. However, the introduction of product standards to avoid or minimise contamination could further reduce any ill effects.

The greater potential risks, and much of the controversy, arise from the relationship between e-cigarette use and tobacco smoking. There are concerns about sustained dual use in smokers who might otherwise have quit completely and also that continued use of e-cigarettes might make relapse to smoking more likely among those who have quit tobacco completely. Although it is too early to tell whether smokers who quit smoking with e-cigarettes are more likely to relapse than are those who use other methods, no evidence as yet shows that dual use results in reduced quit rates.

For non-smokers, the worry is that using e-cigarettes will either lead to nicotine addiction and sustained use or act as a gateway to smoking. Again, no evidence suggests that either of these outcomes is occurring to an appreciable degree. Some non-smoking young people are trying e-cigarettes, but in very small numbers, and any gateway risk should be assessed in the context that nearly one in five 16–19 year olds in Britain has already become a regular tobacco smoker. Given the small risks of exclusive e-cigarette use, progression to tobacco use will thus be a problem only if it adds to the total number taking up tobacco smoking. 

In practice, new users of e-cigarettes are probably most likely to come from the same population of young people who currently experiment with tobacco. The available data suggest that, in any case, young non-smokers are not keen on e-cigarettes, and data from Poland suggest that most of the interest in young age groups arises, as in adults, from those who already smoke tobacco.

Much concern has been expressed that use of e-cigarettes in public, especially in places where tobacco smoking is prohibited, undermines the denormalisation of smoking achieved in recent years and hence promotes smoking. Concerns about renormalisation through use in places where smoking is prohibited assume that e-cigarettes and tobacco cigarettes look so similar that non-smokers, and particularly children, cannot tell the difference, which is unlikely. E-cigarettes – especially later generation products – clearly look different, and the odourless vapour that they produce is quite different from tobacco smoke. 

Advertising for e-cigarettes, much of which is reminiscent of that for cigarettes from decades ago, could actually promote tobacco smoking, some argue. This issue could be resolved by appropriate regulation and prescreening, as applies to medicines, but action is probably needed to prevent inappropriate advertising. Perhaps of more concern is the fact that these effects are a key driver of the growing involvement of multinational tobacco companies in the e-cigarette market, providing these companies with opportunities to circumvent restrictions imposed by the Framework Convention on Tobacco Control on engagement of the tobacco industry with policy-makers. This issue of tobacco industry manipulation to undermine tobacco control policy should be resolvable through stricter adherence to the convention. 

E-cigarettes as cessation or harm reduction products 

Although evidence is limited, first generation cigalike products probably deliver a similar amount of nicotine to Nicorette Inhalators, and are about as effective – but no more effective – as cessation therapy as are transdermal nicotine patches. Later generation vapourisers might be more effective in terms of nicotine delivery, which is likely to improve further as the technology develops. The strength of e-cigarettes in health terms probably lies less in their ability to compete as pharmacological therapies than in their consumer acceptability, wide availability, non-medical image and price advantage over cigarettes. Although trends in the use of nicotine products in smokers show that e-cigarettes have displaced some conventional use of nicotine replacement therapy, particularly over-the-counter sales, they seem to have led to a substantial increase in the proportion of smokers and ex-smokers using an alternative source of nicotine. 

E-cigarettes thus appear to be providing smokers with a valuable alternative route to smoking cessation. However, switching to e-cigarettes without behavioural support is probably far less effective than use in conjunction with the support currently offered alongside licensed drugs by NHS Stop Smoking Services. Unfortunately, the unlicensed status of e-cigarettes precludes endorsement by the NHS or organisations such as the National Institute for Health and Care Excellence (NICE). This situation will probably change this year, however, when the first licensed e-cigarettes are likely to emerge on the market. 

UK regulation 

E-cigarettes are marketed in the UK as consumer products, and are thus exempt from medicines and tobacco regulations. Suppliers have no obligation to provide data for the performance of the products they sell, and few do. In 2013 the Medicines and Healthcare Products Regulatory Agency announced their intention to regulate e-cigarettes as medicines from 2016, using a streamlined light touch approach to apply medicines standards of purity and delivery, and prescreen advertising to prevent marketing abuse. 

In a parallel development, under the revised European Union Tobacco Products Directive, unlicensed e-cigarettes will become subject to tobacco regulation, which prohibits advertising, requires a health warning to be printed on packs, and will impose as yet unspecified purity standards from 2017. Although medicines licensing increases manufacturing costs, licensed products in the UK qualify for 5% rather than 20% sales tax, will be available on prescription through health services as well as on general sale, and can be advertised as cessation or harm reduction products. It is therefore likely that while some suppliers will opt for regulation as a tobacco product, others will opt for medicines regulation. In either case, these forms of regulation will resolve many of the concerns outlined above. 

Despite the controversies, it is clear that e-cigarettes are far less hazardous than is tobacco. With more than a million UK smokers using them to help to cut down or quit smoking, they are proving to be valuable harm reduction and cessation products and could make a substantial contribution to reducing the burden of death, disability and poverty currently caused by tobacco smoking. Health professionals should embrace this potential by encouraging smokers, particularly those disinclined to use licensed nicotine replacement therapies, to try them, and, when possible, to do so in conjunction with existing NHS smoking cessation and harm reduction support. E-cigarettes will save lives, and we should support their use.

The views expressed are those of the authors.


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A step in the right direction

It is about time that these products are recommended for smoking cessation. They are clearly far safer than tobacco, and patients are more likely to quit smoking using e-cigarettes rather than conventional nicotine replacement therapy if the device has the look and feel of a cigarette.

electronic smoking in public

It is not clear that e-smoking will be always prohibited in the same way as conventional tobacco as for example in private clubs. Will e -cigarettes be prohibited in cars carrying children? Are there potential hazards from nicotine in passive smoking? The passive smoke certainly will cause upper respiratory irritation. There must be safeguards for other than smokers.

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