The growingly popular electronic cigarettes are one form of “Electronic nicotine delivery systems”, or “ENDS”. They use a heating element to heat a solution that is vaporized and delivered to the user in the form of an aerosol. The main constituents of this solution are propylene glycol and flavoring agents, in addition to nicotine, which is not always present.
Some experts welcome ENDS as a pathway to the reduction of tobacco smoking, while others characterize them as products that could undermine efforts to denormalize tobacco use. ENDS, therefore, represent an evolving frontier, filled with promise and threat for tobacco control.
What are the products available, and what is the market for them?
Electronic nicotine delivery systems use a heating element to vaporize a solution into an aerosol. But there is a wide range of different products, and the way the devices are used may affect nicotine absorption; length of puffs, depth of inhalation and frequency of use may be such influencing factors. In addition, some users modify products to alter delivery of nicotine and/or other drugs.
The market seems to be booming. It is estimated that in 2014 there were 466 brands and that in 2013, US$ 3 billion was spent on ENDS globally. Sales are forecasted to increase by a factor of 17 by 2030. In 2012, 7% of EU citizens aged 15 years and over had tried electronic cigarettes. Users report that the main reasons for using ENDS are to reduce or stop smoking and because they can be used in smoke-free places.
Are there health risks associated with electronic nicotine delivery systems” (ENDS)?
Most ENDS products have not been tested by independent scientists but the limited testing has revealed wide variations in the nature of the toxicity of contents and emissions.
What is clear is that there are health risks associated with nicotine inhalation. Nicotine is addictive, and can contribute to cardiovascular disease. It can have adverse effect during pregnancy, and although it does not cause cancer by itself, it can function as a ‘cancer promoter’. The evidence is sufficient to caution children and adolescents, pregnant women, and women of reproductive age about ENDS use, because of the potential for fetal and adolescent nicotine exposure to have long-term consequences for brain development.
The inhalation of the aerosols delivered by electronic systems can have some effects on health. Eyes and lungs can get irritated by exposure to propylene glycol, for instance. The existing evidence shows that ENDS aerosol is not merely “water vapour” as is often claimed in the marketing for these products. ENDS use poses serious threats to adolescents and fetuses.
Given the relatively short time since those products have entered the market and the lag time of many diseases such as cancer, there is, as of now, no conclusive evidence about the health risks of ENDS, and this evidence won’t likely be available for years or even decades. However, it is very likely that average ENDS use produces lower exposures to toxicants that combustible products.
Bystanders can be exposed to second-hand aerosol that increases the background level of some toxicants, of nicotine, and of fine and ultrafine particles in the air. Exhaled aerosol is likely to increase above background levels the risk of disease to bystanders in the case of some ENDS that produce toxicant levels in the range of that produced by some cigarettes. If the levels emitted by ends are generally much lower than by conventional cigarettes, it is however unknown if this exposure will lead to an increased risk of disease among bystanders.
Are electronic nicotine delivery systems an effective way to stop smoking and to get rid of nicotine dependence?
Although anecdotal reports indicate that some ENDS users have quit smoking using these products, their efficacy has not been systematically evaluated yet. It is likely that the use of ENDS will help some smokers to quit cigarettes, but more likely to simple reduce the number of cigarettes and not quit entirely. Since it appears that the number of years of smoking is a more important factor than the intensity of smoking in generating health problems, dual use will have much smaller beneficial effects on overall survival compared with quitting smoking completely.
Have these substitutes an impact on existing tobacco-control efforts?
Although electronic nicotine delivery systems may present a range of potential benefits to smokers, there is an extensive and often heated debate about whether these will prove to have a positive or negative impact on population health and particularly tobacco control. Areas of legitimate concern include avoiding nicotine initiation among non-smokers and particularly youth while maximizing potential benefits for smokers. A report considered that ENDS would provide public health benefits only in an environment where the appeal, accessibility, promotion, and use of cigarettes and other combusted tobacco products are being rapidly reduced.
What are the recommendations of the World Health Organisation (WHO) regarding these products?
WHO reiterated that smokers would obtain the maximum health benefit if they completely quit both tobacco and nicotine uses. In the context of the framework convention on tobacco control, the WHO recommends that electronic nicotine delivery systems should be regulated and this should be done on a robust scientific background, which is not currently available.
More specifically, the promotion of ENDS should be impeded, as is their uptake by non-smokers, pregnant women and youth. Unproven health claims should be prohibited from being made about ENDS, and existing tobacco-control efforts should be protected from commercial and other vested interests of the tobacco industry.