18B.6Potential negative impacts

Material under review: November 2017     

Suggested citation: Greenhalgh, EM, & Scollo, MM. InDepth 18B: Electronic cigarettes (e-cigarettes). In Scollo, MM and Winstanley, MH [editors]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2017. Available from: http://www.tobaccoinaustralia.org.au/chapter-18-harm-reduction/indepth-18b-e-cigarettes

At the heart of the debate over the utility of e-cigarettes is concern about the extent to which the potential benefits of making a likely-less harmful alternative to tobacco widely available to smokers might be outweighed by several potential risks. Risks identified to date include uptake by non-smokers, gateway effects, dangers associated with dual use, discouragement from cessation, renormalising smoking, and allowing the tobacco industry to influence decision-making in public health.1-3

18B.6.1.Uptake among non-smokers and a ‘gateway effect’ to tobacco smoking

Experimentation with e-cigarettes among non-smoking adults appears to be relatively rare.4, 5  Among young people however, use is increasing, in some countries quite rapidly (see Section 18B.3). While initial reports indicated that e-cigarette use occurred predominantly among adolescents who had also experimented with tobacco,6 more recent data shows increasing use among never smokers.7 An analysis of trends from 2011 to 15 in e-cigarette use among US adolescents found that over time, past month e-cigarette users increasingly encompassed those who were not users of other tobacco products.8 In 2016 in the US, e-cigarettes remained the most commonly used tobacco-related product among students.9

Of great concern to public health experts is the growing body of research suggesting a possible relationship between e-cigarette use and the uptake and escalation of smoking among young people.  A large longitudinal study of Californian high school students has suggested that e-cigarettes are attracting users who would not have taken up combustible tobacco products.7 A number of studies in the US have observed an association between e-cigarette use and intention/willingness to smoke in the future,10-12 and subsequent tobacco use.13-19 A 2016 meta-analysis concluded that never-smoking adolescents and young adults who use e-cigarettes are more likely to intend to smoke,20 and a systematic review in the same year concluded that e-cigarette use is associated with an increase in smoking, even among adolescents not susceptible to smoking.21 A more recent study in the UK found a robust relationship between ever-use of e-cigarettes and subsequent uptake of smoking among adolescents, and weaker evidence of a relationship between e-cigarette use and increasing consumption of conventional cigarettes.22   

Such studies cannot establish causation (i.e., vaping could be a marker in young people who would have gone onto use conventional cigarettes regardless; one cannot rule out the possibility that the relationship between e-cigarette use and smoking is explained by another/other variable/s). However several studies have noted conventional cigarette uptake among e-cigarette users who would be considered least at risk of smoking,13, 21, 22 and the best-quality studies and reviews have attempted to control for underlying susceptibility. Several possible mechanisms of how vaping may act as a ‘gateway’ to smoking have been proposed. E-cigarette use could normalise nicotine use and smoking behaviours more generally, leading to the renormalisation of smoking, or it could cause users to develop nicotine addiction.20, 22   

Regardless of whether they go on to be smokers, use of e-cigarettes by children is a concern to public health specialists and regulators. Exposure to nicotine during adolescence may have significant and lasting health consequences,23 including long-term addiction to e-cigarette delivered nicotine.24 Further, although the adverse health effects of e-cigarette use are likely less than those of cigarettes, the long-term consequences are not well understood. Limited evidence suggests that vaping—particularly when e-liquids include sweet flavourings25, 26 —may increase users’ risks of cardiovascular and respiratory disease (see Section 18B.5). Some adolescents are also using e-cigarettes for vaping of cannabis and other substances which pose additional risks.27   

As with tobacco cigarettes, exposure to e-cigarette marketing and promotion is associated with greater e-cigarette use among young people,28-31 with ads for flavoured e-cigarettes potentially being more appealing to children than those for non-flavoured products32 (see Section 18B.2.3). Along with curiosity, the wide range of fruit, candy, and other sweet flavours is one of the most commonly cited reasons for experimentation among children.33-36 Although such flavours have been banned in conventional cigarettes in Australia (except WA)37-43 and the US44 largely due to their appeal to children, and despite the high levels of toxic compounds found in flavoured e-cigarettes,45, 46 it has been estimated that there are over 7500 different flavours of e-liquid available.47

Together, these issues have led to calls for strict regulations that would minimise use among young people and non-smokers, including restrictions on advertising and promotion, prohibiting use in smokefree areas, banning flavours that could appeal to youth, raising taxes, implementing health warnings, and prohibiting sales to minors.48, 49   

18B.6.2 Prolonged dual use 

Dual use refers to the concurrent use of conventional tobacco products and e-cigarettes.  Dual use is actively promoted by some e-cigarette manufacturers, especially those that also manufacture tobacco products, as a way for smokers to by-pass smokefree regulations.50 Other smokers use both products as a means of reducing their exposure to tobacco smoke, and/or as an intended pathway to smoking cessation.51 A 2016 meta-analysis concluded that cigarette smoking increases the probability of e-cigarette use, especially among current smokers and adolescents.52

While a reduction in risk seems likely for smokers who completely substitute tobacco cigarettes,53, 54 the benefits for those who continue to use some tobacco cigarettes are much less certain. Among those who exclusively smoke tobacco cigarettes, cutting down the number of cigarettes consumed may not reduce toxic exposure if smokers compensate by drawing more deeply on the cigarettes they do smoke. There is some evidence that supplementing reduced cigarette consumption with an alternative source of nicotine might reduce toxicant exposure and hence mortality among smokers who continue to smoke at a reduced rate—see section 18B.7.3.55-57 However, there are no long-term studies to measure whether long-term dual use translates into measurably better health outcomes compared to continued smoking of cigarettes alone.

18B.6.3 Discouragement from cessation

Smokers taking up e-cigarettes while still smoking tobacco cigarettes, who might otherwise have quit altogether had they not commenced e-cigarette use, might represent missed opportunities for complete cessation. So far, research on the likelihood of dual use of cigarettes and e-cigarettes prompting or supporting cessation is limited.  While cutting down cigarettes has been associated with later increased success in quitting, the evidence for improved cessation rates among those who supplement tobacco cigarettes with e-cigarettes is mixed. Evidence to date suggests that smokers who use e-cigarette intensively may be more likely to quit conventional cigarettes,58-61 however intermittent users—who comprise the majority of users—may be less likely to quit58, 61 (see Section 18B.7).

Smoking poses a very significant risk to health both in the immediate and the longer term, but the most serious diseases emerge only with long-term use. While two of every three long term smokers in Australia will die from smoking, quitting prior to age 45 reduces mortality risk close to that of never smokers.62 Given that complete cessation of use of any nicotine product is the option associated with least harm, it follows that the optimal approach for younger smokers at least in the first instance would be to attempt to quit without continuing use of nicotine. 

18B.6.4 The renormalisation of smoking 

Decades of successful public health campaigning have profoundly denormalised smoking. As evidence has accumulated about the hazards of tobacco to smokers and non-smokers alike, stronger public health measures—including restrictions on smoking—have been widely adopted.63 Those advocating caution about e-cigarettes have characterised these new products as having the potential to weaken these tobacco control efforts and help to renormalise smoking, particularly if they are used in smokefree areas.63, 64   

It has also been argued that e-cigarettes could revive the behaviour of smoking in public, undermining increasingly stringent restrictions on smoking in both indoor and outdoor areas.1 Along with cessation, a study of older adults in the US found that they reported using e-cigarettes as a way to circumvent no-smoking policies, and perceived e-cigarette marketing as a way to renormalise smoking.65 An alternative view is that e-cigarettes are easily distinguishable in appearance and smell from tobacco cigarettes, and that widespread use of e-cigarettes is more likely to normalise alternative nicotine devices than smoking, and may benefit and support smokefree environments.6  

18B.6.5 Potential to reinvolve the tobacco industry in public health policy 

Although e-cigarettes were originally developed and marketed independently from the tobacco industry, some of the world’s largest tobacco companies have  come to dominate the market—see Section 18B.1.3. Given its history of unethically promoting and defending tobacco cigarettes, the tobacco industry’s involvement in e-cigarettes is of great concern to public health experts. The tobacco industry is said to be pursuing five goals: promoting widespread dual use; hindering smoking cessation; renormalising public smoking; conveying to young people that nicotine is a benign drug; and welcoming back lapsed smokers.1 Concerns have also been raised regarding the quality of research on e-cigarettes, with one systematic review finding many serious methodological shortcomings. In 34% of the papers reviewed, the authors had a conflict of interest. Most studies were funded or otherwise supported/influenced by manufacturers of e-cigarettes, which appeared to influence the conclusions of the papers.66

As well as enjoying commercial gains from investing in e-cigarettes, it has been argued that tobacco companies are likely to be keen to exploit opportunities for advertising and promotion that will promote tobacco and/or e-cigarette use. By becoming involved in alternative nicotine delivery products, companies may be able to evade current restrictions on engagement in policy imposed by Article 5.3 of the Framework Convention on Tobacco Control (FCTC).6 In response to concerns regarding the possibility of e-cigarettes interfering with existing tobacco control efforts, the WHO has invited FCTC Parties to “protect tobacco-control activities from all commercial and other vested interests related to [electronic nicotine delivery systems], including interests of the tobacco industry”.67   

 

Relevant news and research

For recent news items and research on this topic, click here (Last updated September 2018)    

 

References 

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