18B.7Population-level benefits and harms of increasing e-cigarette use

Last updated: October 2021 

Suggested citation: Greenhalgh, EM, & Scollo, MM. 18B.7 Population-level benefits and harms of increasing e-cigarette use. In Greenhalgh, EM, Scollo, MM and Winstanley, MH [editors]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2021. Available from:  http://www.tobaccoinaustralia.org.au/chapter-18-harm-reduction/indepth-18b-e-cigarettes

 

Given the uncertainty of the effects of the rapid increase in e-cigarette use on smoking behaviours and public health, several comprehensive reviews have attempted to synthesise all available evidence on the potential risks and benefits of e-cigarettes for both smokers and non-smokers. The US National Academies of Sciences Engineering and Medicine concluded in 2018 that, based on its findings, e-cigarettes cannot be simply categorised as either beneficial or harmful to health.1 The CSIRO in Australia similarly concluded in 2018 that based on the evidence, it was not possible to determine whether e-cigarettes have a positive or a negative effect on health in countries where they are permitted.2 Public Health England, while noting that more research is needed on the use of e-cigarettes among particular groups and the different types and strengths of products, supports the availability and use of e-cigarettes for smoking cessation in its latest evidence review.3

The availability and regulation of e-cigarettes continues to be a fraught issue among public health researchers and policy makers.4 In light of the rapidly evolving evidence and uncertainty surrounding the products, Australian researchers have attempted to develop a framework for assessing the public health impact of e-cigarettes and to inform the development of evidence-based policy. The framework comprises seven components: (1) characterisation of products under consideration; (2) definition of populations of interest; (3) characterisation of exposure to tobacco smoking, control and impacts on health and well-being; (4) review of evidence on patterns of e-cigarette use; (5) review of evidence on the relationship of e-cigarette use to health outcomes ; (6) assessment of likely risks, benefits and safety and (7) identification and assessment of policy options to optimise health outcomes. Consideration of each of these components—and reconsideration as more evidence becomes available—can guide high-quality decision making on e-cigarettes.5 Discussion of e-cigarettes in Tobacco in Australia follows this model. Section 18B.1 characterises e-cigarette products and Section 18B.2 describes how these are advertised and promoted to populations of interest. Section 18B.3 sets out available data about extent of use of e-cigarette products in Australia. Section 18B.4 summarises safety risks. Section 18B.5 summarises the findings of a rapidly growing body of research on the potential health effects of use of e-cigarettes. Section 18B.6 provides an overview of the evidence on the effects of e-cigarette use on smoking uptake and cessation.

This section (section 18B.7) focuses on potential population-level impacts, including:

  • an overview of studies that have modelled population-level effects of e-cigarette use and availability
  • the possibility that e-cigarette use could renormalise smoking, and
  • the potential for the tobacco industry—which is increasingly investing in e-cigarettes—to become re-involved in public health policy.

18B.7.1 Modelling of net impact of use of e-cigarettes on smoking prevalence and tobacco-related disease

Using data generated from reviews of the evidence to date about effects of e-cigarette use on smoking behaviour and making varying assumptions about effects on risk of major health conditions, several researchers have attempted to model hypothetical scenarios and estimate possible outcomes of e-cigarette use on smoking behaviours and public health. The usefulness of such modelling is of course limited by the absence of data on long-term health effects, difficulties of precisely quantifying the effects on smoking uptake and continuing uncertainty about effectiveness for cessation. Conclusions consequently vary substantially depending on the assumptions and parameters used by researchers.

One early study modelled the potential future effects of e-cigarette use on smoking behaviour and noted that, based on current usage patterns, smoking prevalence appears to be far more sensitive to e-cigarette effects on smoking cessation than on smoking initiation. Results from the model suggested that if e-cigarettes increase both uptake and quitting of conventional cigarettes, the effects on uptake would have to be extremely large (i.e., increase over 200%) to offset even small cessation effects on population smoking prevalence.6 It is not surprising then, that models that assume optimistic estimates of likely effects on smoking cessation tend to find high net positive benefits for increasing population use of e-cigarettes.

A modelling study of the health and cost impacts of e-cigarettes in New Zealand concluded that a fairly permissive regulatory environment achieves net health gain and cost savings. However, there was a large degree of uncertainty for this finding, given the uncertainty around the impact of vaping on cessation rates and the relative health risk of vaping compared with smoking.7 Updated modelling in New Zealand using less optimistic estimates about cessation effects and less optimistic assumptions about potential reductions in health effects however found that while net health and cost-saving benefits were still likely from the liberalisation of access to e-cigarettes, the revised estimates suggest these gains and savings would be of smaller magnitude than previously thought, with a greater possibility of there being no net health gain or even net health harm.8         

US researchers have concluded that a substantial gateway effect (of vaping to smoking by never smokers) or an increase in the magnitude of harms from e-cigarettes relative to cigarettes (or both) would be required before the harms to public health outweigh the benefits of e-cigarette uptake. The authors estimate a net public health benefit associated with e-cigarettes resulting in 21% fewer smoking-attributable deaths and a 20% reduction in life years lost.9 A more recent modelling study by some of the same researchers concluded that, under an ‘optimistic scenario’, replacement of cigarette by e-cigarette use over a 10-year period would yield 6.6 million fewer premature deaths with 86.7 million fewer life years lost. Even under pessimistic assumptions regarding cessation, initiation and relative harm, they argue that replacing cigarette smoking with vaping would yield substantial life year gains, particularly among younger cohorts.10

Updates of these studies that modelled smoking outcomes in England and the US concluded that e-cigarette use is associated with substantial reductions in smoking prevalence and smoking-attributable deaths— 0.4 million averted deaths between 2012 and 2052 in the US,11 and 165,660 in England.12 However, these studies only considered the outcomes for smoking, and not health outcomes or uptake/gateway effects. When the researchers more broadly modelled the effects of e-cigarette use on public health they found that it would translate to 1.8 million premature smoking-attributable and vaping-attributable deaths avoided and 38.9 million life-years gained during the period 2013–2060, but noted the uncertainty of future trends given unknown use behaviours and regulations.13 Additional modelling studies in the US also found that e-cigarette use was likely to reduce smoking-attributable deaths;14, 15 however one study notes that this would only represent a small fraction of such deaths, and emphasises the importance of continued existing evidence-based tobacco control measures in order to reduce smoking-related harms.15  

In contrast to the modelling studies that find net population benefits of e-cigarette use, modelling studies with less optimistic assumptions about cessation effects and more pessimistic assumptions about effects on uptake tend to find net population harm. A collaboration of researchers with expertise in youth smoking uptake have estimated that e-cigarette use in 2014 represents a population-level harm in the US of about 1.6 million years of life lost over the lifetime of all adolescent and young adult never-cigarette smokers and adult current cigarette smokers. If e-cigarette use confers long-term health risks, the model estimated even greater population-level harm. They argue that previous models—which reached more favourable conclusions about the public health impact of e-cigarettes—are based on faulty assumptions about uptake and smoking initiation among young people.16

Another study that modelled the potential health effects of increasing e-cigarette use concluded that—in order for there to be any benefits to public health—most e-cigarette users need to be current smokers interested in quitting or people who would have otherwise gone on to be smokers.  Other scenarios, such as e-cigarette use renormalising smoking, dual use, or significant uptake by young people (those young people who would otherwise never have smoked tobacco cigarettes) have the potential to increase population-level harm. The authors suggest that the likelihood of negative scenarios eventuating will ultimately depend on the regulatory environment, with benefits to public health being more probable with strict regulations on the sale, promotion, and use of the products; i.e., regulations that encourage use only by smokers,17  and only without simultaneous use of tobacco products.

Researchers in Singapore modelled the potential impact of different e-cigarette and tobacco cigarette policies over 50 years, combining evidence from Singapore (where e-cigarettes are currently banned) with evidence from Japan, the UK and the US (where e-cigarettes are much more widely accessible). The study concluded that while a less restrictive e-cigarette policy could reduce smoking prevalence in the short term, it is not as effective as other policies in the long term. The most effective single policies were ‘smokefree generation’ and substantial tax increases; the most effective combination of policies was raising the minimum legal age plus moderate tax increases and e-cigarettes on prescription.18

A review published in 2021 critically appraising all these modelling studies concluded that while most suggest that the introduction of modified risk tobacco products would have a beneficial population health impact, the predictions are based on a number of factors and assumptions for which epidemiological evidence is lacking.19 Overall, any population-level effects may include some groups incurring harm (e.g., young people who would not otherwise have smoked who take up vaping or who start smoking), and some incurring benefits (e.g., smokers who quit). Changing cessation rates are seen earlier than the effects of changing initiation rates, due to the health effects of smoking taking many years to manifest. Conclusions of various models will therefore vary based on whether the projections are short- or long-term, with potential harms from increased initiation by youth occurring decades after the benefits of increased cessation are seen.1

18B.7.2 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.20 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.20, 21 E-cigarette use among young people is especially worrying if e-cigarettes promote the normalisation of nicotine use and smoking behaviour, and subsequently lead to long-term use among those who would otherwise never have vaped or smoked.1 Research has found that exposure to e-cigarette use among young people increases their likelihood of using e-cigarettes—see Section 18B.12.6.4. Along with being more susceptible to vaping, data from a nationally representative survey of US secondary school students showed that observation of e-cigarette use at school was associated with significantly higher odds of being susceptible to smoking cigarettes, especially among middle-school students.22 Californian research similarly found that adolescents who had a family member or peer that used e-cigarettes reported more positive attitudes about and greater willingness to take up smoking.23

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.24 Dual users of e-cigarettes and cigarettes commonly report using the products to circumvent no-smoking policies,25-27 and in the face of increasing restrictions on e-cigarette use in smokefree environments, many users report using e-cigarettes discreetly in places where such use is prohibited.28 British American Tobacco has promoted its e-cigarette products to investors as a means of increasing the frequency of nicotine use, including at home, commuting to work, at work, and in bars where smoking is now less acceptable.29 However, it is unclear whether the growing acceptance and use of e-cigarettes affects acceptance of cigarette smoking, or levels of support for regulations to discourage smoking.2 Research in the US found that one in five high school students who had never used tobacco products reported exposure to secondhand e-cigarette aerosol in public, which was associated with overestimation of peer use for both e-cigarettes and conventional cigarettes, as well as increased curiosity and susceptibility to e-cigarettes and cigarettes.30 On the other hand, some have argued 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.31 Researchers in Great Britain found that positive perceptions of smoking attitudes among young people declined at a faster rate following the proliferation of e-cigarettes.32

Norms among adult smokers and vapers towards e-cigarettes appear to reflect country regulations, such that people in countries with less restrictive policies (England, Canada and the US) are exposed to more e-cigarette use in public and are more likely to report that society and people important to them approve of e-cigarette use compared with people in countries with more restrictive policies (such as Australia).33 In 2019, about two-thirds of Australians indicated that they would support restrictions on vaping in public places and on e-cigarette advertising, and about four in five supported restricting sales to people aged 18+.34 Patterns are less clear among teenagers. Research in 2017 found that while young people in Canada, England, and the US had more pro-vaping than pro-smoking norms overall, English young people reported the most pro-smoking but least pro-vaping norms compared with Canadian and US teens.35

18B.7.3 Potential to re-involve 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 subsequently heavily invested in 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.24 One paper concluded that there is little evidence to support claims that tobacco companies are moving away from the combustible cigarette market, and instead may be using investment in e-cigarettes to strategically position themselves as legitimate stakeholders in research and policy debates.36

Following decades of interference in tobacco control policy—see InDepth 10A—the tobacco industry has been adopting a range of tactics to prevent or weaken e-cigarette regulations. Common strategies that have been reported include lobbying decision makers (see also Section 18B.1.4), funding research (see below), running public relations campaigns, attempting to discredit those working in tobacco control,37 using international trade and investment agreements to challenge regulations,38 and creating front groups.37 For example, the Foundation for a Smoke-Free World, while claiming its mission is to eliminate smoking and encourage a shift to ‘reduced harm’ products, is funded by Philip Morris International who continue to oppose and undermine effective tobacco control policies.39 Philip Morris has also funded retail groups in Australia that have lobbied for weaker e-cigarette regulations,40 and Philip Morris and Imperial Brands have also reportedly sent pro-e-cigarette messages and/or requested meetings with Australian MPs in recent years.41 While the Australian Labor Party, Liberal Party, and Greens do not accept donations from the tobacco industry, the Nationals and Liberal Democrats have continued to receive donations—see Section 10A.7.3.

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 (including the tobacco industry), which appeared to influence the conclusions of the papers.42 Another analysis found that while almost all papers published on e-cigarettes and health without a conflict of interest found potentially harmful effects, less than eight per cent of tobacco industry-related studies reported potential harm. Tobacco industry papers were cited more often than papers written by independent researchers.43 A systematic review published in 2019 found that research funded by the e-cigarette, tobacco, or pharmaceutical industry was significantly associated with a supportive stance on tobacco harm reduction compared with non-industry funded articles,44 and a 2021 review of public health recommendation documents from the WHO, UK, Australia and the US found that many drew on evidence that contained substantial conflicts of interest, including funding from e-cigarette and tobacco companies.45 An additional concern is the selective or non-reporting of trial outcomes, with an analysis finding that Juul Labs had not completely reported the findings from its registered clinical trials.46

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.31 Many e-cigarette advertisements resemble traditional tobacco advertising.47 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).31 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”.48

 

Relevant news and research

For recent news items and research on this topic, click  here. ( Last updated February 2022)

 

References  

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