Comments on the SCHEER Preliminary Opinion on electronic cigarettes

*SCHEER Preliminary Opinion on electronic cigarettes

– ABSTRACT: ”The overall weight of evidence for risks of long-term systemic effects on the cardiovascular system is strong.” 
(Page 2, lines 13-14).
– SCIENTIFIC OPINION: Overall assessment for electronic cigarette
(page 15, lines 5-17)
– RATIONALE: 6.5.4 Human evidence for health impacts of electronic cigarettes/Cardiovascular diseases
(page 47, line 27 – page 48, line 47)
– RATIONALE: Conclusions/Cardiovascular diseases
(page 61, lines 15-27)

Most e-cigarette users are smokers/ex-smokers, so they already have a higher than average risk of heart problems. An association observed in some studies between the use of e-cigarettes and the increased risk of heart disease is therefore more likely to be explained by past, possibly very long-lasting smoking, than with the current use of e-cigarettes.

For example, the Bhatta & Glantz -study (2019) found an association between the use of e-cigarettes and increased risk of heart attack, but the association disappeared when those users who had had a heart attack before starting to use e-cigarettes were excluded from the analysis (the study has since been retracted).

The potential heart risks of e-cigarettes are primarily associated with nicotine. The cardiac effects of nicotine are however mild and transient, and no problems have been observed with long-term use of, for example, pharmaceutical nicotine replacement products. In a systematic review published in 2018 (Rostron et al.), Swedish-type snus was not found to increase the risk of cardiovascular disease.

The heart risks of smoking are mainly caused by harmful substances generated during combustion. There is no combustion in e-cigarettes, so switching from smoking to e-cigarette use results in significant benefit to heart health (Benowitz et al., 2016).

A study published in 2019 (George et al.) found a significant improvement in heart health as early as one month after switching from smoking to e-cigarette use. Another recent study found that switching from smoking to e-cigarette use reduced arterial stiffness and oxidative stress after four months of use (Ikonomidis et al., 2020).

1_1 Rodu
1_2 Rostron:
1_3 Benowitz:!po=3.33333
1_4 George:
1_5 Ikonomidis:

– ABSTRACT: ”The overall weight of evidence for risks of carcinogenicity of the respiratory tract due to long-term, cumulative exposure to nitrosamines and due to exposure to acetaldehyde and formaldehyde is weak to moderate.”
(Page 2, lines 15-17)
– SCIENTIFIC OPINION: Evidence for risk for carcinogenicity of the respiratory tract due to long-term, cumulative exposure to nitrosamines and due to exposure to acetaldehyde and formaldehyde
(page 15, lines 19-34)
– RATIONALE: The overall weight of evidence for risk of respiratory tract carcinogenicity due to long-term, cumulative exposure to nitrosamines and due to exposure to acetaldehyde and formaldehyde
(page 61, line 29 – page 62, line 5)

Studies to date have estimated the risk of cancer from the use of e-cigarettes to be very low. For example, a study by Stephens (2017) estimates that the risk of cancer is generally <1% of the risks of smoking and a Public Health England review (2018) estimates the cancer risk to be largely less than 0.4%.

A Kosmider et al. study (2020) on acetaldehyde and formaldehyde exposure from e-cigarettes found the cancer risk to be 3117-21818 times smaller compared to smoking.

A study by Cancer Research UK (2017) found long-term users of e-cigarettes to have levels of carcinogens and toxicants comparable to users of pharmaceutical nicotine replacement products.

2_1 Stephens:
2_2 PHE:
2_4 Kosmider:
2_5 Shahab:


– ABSTRACT: ”SCHEER concludes that there is strong evidence that electronic cigarettes are a gateway to smoking for young people.”
(Page 2, lines 43-44)
– SCIENTIFIC OPINION: Role of electronic cigarettes as a gateway to smoking/the initiation of smoking, particularly for young people
(page 16, line 27 – page 18, line 39)
– RATIONALE: Health effects of electronic cigarette use on young populations, children and adolescents
(page 52, lines 13-49)
– RATIONALE: Role as a gateway product or renormalisation of traditional tobacco smoking
(page 67, lines 11-24)
– RATIONALE: Experimentation with tobacco products among non-tobacco using youth that experiment with electronic cigarettes (gateway)
(page 67, line 26 – page 68, line 8)
– RATIONALE: Experimentation with electronic cigarettes among non-smoking adults and youth in the EU
(page 69, line 10 – page 70, line 15)

E-cigarettes have not acted as a gateway to smoking, but if a gate is to be seen, it is away from smoking. Smoking has not increased, but has decreased faster than before alongside the increase in the use of e-cigarettes. One obvious reason for this is that most users of e-cigarettes are smokers or ex-smokers. Instead, regular use of e-cigarettes among never-smokers has remained very low (<1%).

3_1 Levy:
3_2 ASH:
3_3 Glasser:
3_4 ASH:
3_5 Zhu:


– ABSTRACT: ”There is also strong evidence that […] flavours have a relevant contribution for attractiveness of use of electronic cigarette and initiation.”
(Page 2, lines 44-47).
– SCIENTIFIC OPINION: Role of electronic cigarettes as a gateway to smoking/the initiation of smoking, particularly for young people 
(page 17, line 34 – page 18, line 39)
– RATIONALE: Role in the initiation of smoking (particularly focusing on young people/Flavours
(page 64, line 34 – page 66, line 2)

Flavours are an essential part of the use of e-cigarettes, without which e-liquids would be in practice tasteless. A range of flavours corresponding to different taste preferences is also needed because e-cigarettes cannot realistically mimic the taste of smoking cigarettes.

Smokers who have quit or are trying to quit smoking find flavours to be important when replacing cigarettes with e-cigarettes. According to a survey in 2018 (Farsalinos et al.), comprising of about 70,000 adult users of e-cigarettes, the majority of adult users, about 90%, use flavours like fruit, confectionery, dessert, etc. So these flavours are by no means particularly favored by youth.

Flavours are not the main reason for young people’s e-cigarette experiments, but curiosity and the same risk predisposing factors than in young people experimenting with tobacco. Because of this, young people who try e-cigarettes are largely the same young people who are potentially likely to try smoking cigarettes.

4_1 Farsalinos:
4_2 Russell:
4_3 Kim:
4_4 Kinouani:


– ABSTRACT: ”SCHEER concludes that there is weak evidence for the support of electronic cigarettes effectiveness in helping smokers to quit while the evidence on smoking reduction is assessed as weak to moderate.”
(Page 2, lines 50-52).
– SCIENTIFIC OPINION: 3. Role of electronic cigarettes in cessation of traditional tobacco smoking
(page 18, line 41 – page 19, line 7)
– RATIONALE: 6.7 Role of electronic cigarettes in the cessation of traditional tobacco smoking and dual use
(page 70, line 18 – page 71, line 34)

Multiple studies have shown the use of e-cigarettes to increase the probability of quitting smoking. E-cigarettes have also been proven to be more effective than nicotine replacement products for this purpose. These facts are stated e.g. in a recent Cochrane systematic review of 50 studies.

5_1 Cochrane:


– SUMMARY: ”Some data available from the US indicate that the prevalence of electronic cigarette use is increasing in children and adolescents.”
(Page 8, lines 22-23).

In fact, according to the latest statistics, e-cigarette use among young people in the United States fell this year by about one third compared to last year.

6_1 FDA:


– RATIONALE: 6.2. Design Features: ”It should be noted, that the electronic cigarette brand with the largest US market share (~75% as of 2019 […].”
(Page 21, lines 25-26).

The percentage is incorrect as it only takes into account sales in tracked channels like convenience stores and it doesn’t take into account online sales or sales by electronic cigarette specialty stores.


– RATIONALE: Use in young populations, children and adolescents (USA).
(Page 26, line 27).

The most important information is missing from this section, i.e. the figures describing the regular use of e-cigarettes.

In 2018, of all middle- and high-school students in the United States, 3.6% used e-cigarettes regularly (≥20 days/month) and only 0.4% of never-smoking youth.

At the same time, with the increase in the use of e-cigarettes, young people’s smoking has decreased two to four times faster than before. Currently, about one percent of U.S. youth smokes daily.

3_1 Levy
3_3 Glasser:


– RATIONALE: Exposure to aerosols, qualitative description 
(page 30, line 16 – page 31, line 27)
– Quantification of aerosol concentrations
(page 31, line 55 – page 38, line 12)
– 6.5.3 Hazard identification of most relevant compounds
(page 39, line 26 – page 46, line 15)

In the handling of this topic the level of risk from these exposures has been completely disregarded, i.e., whether the amounts of toxicants released from e-cigarettes are high or low and how they compare to exposures to toxicants from smoking.

The latter information is particularly relevant given that the use of e-cigarettes is mainly concentrated among smokers/ex-smokers and the main purpose of use being smoking cessation, reduction or prevention of relapse to smoking.

Studies have shown that the amount of contaminants released from e-cigarettes is small and the level of risk they represent is low. Compared to cigarette smoke, the levels of harmful substances are substantially lower. Most of the harmful substances in cigarette smoke are not present in e-cigarette aerosol at all, including combustion products, which are primarily responsible for the harmful health effects of smoking.

2_1 Stephens:
2_4 Kosmider:
9_2 PHE: 
9_5 Shahab:


– Second-hand exposure

(page 38, line 14 – page 39, line 24)
– 6.5.4 Health effects related to second-hand exposure to aerosol from electronic cigarettes
(page 51, line 27 – page 52, line 10)
– On risks for second-hand exposure
(page 62, lines 11-43)

Due to the small amount of pollutants released into the environment from e-cigarettes, exposure to aerosols released from e-cigarettes have not been shown to pose a health risk to bystanders. In indoor measurements, pollutant levels have been below permissible limit values.

It should also be noted that there is no side-stream aerosol emitted from the tip of an electronic cigarette, just the exhaled aerosol entering the atmosphere. Particles are liquid droplets that evaporate rapidly, approximately in 10–20 seconds, in comparison with the conventional cigarette particulate emissions which had a dissipation time of approximately 1.4 hours in a 35 m3 room (Lampos et al., 2019).

10_1 PHE: 
10_2 Zwack:
10_3 Klepeis:
10_4 Scungio:
10_5 Lampos:


– RATIONALE: 6.5.4. Lung diseases
(page 49, lines 1-20)

In addressing this issue, it would be important to mention that studies have also found that switching from smoking to e-cigarettes reduces respiratory infections as well as asthma- and COPD symptoms. By focusing solely on the potential risks without putting them into proportion relative to the risks of smoking, this section risks misleading smokers who, by switching to e-cigarettes, would substantially reduce those risk factors.

This is the general problem of this report: given that the user base of e-cigarettes consists primarily of smokers/ex-smokers who use e-cigarettes for smoking reduction or cessation, ignoring the transition from smoking to e-cigarette use and its benefits to health, the report is basically ignoring the central health effects of the use of e-cigarettes among the main user group of these products.

11_1 Polosa:
11_2 Campagna:
11_3 Miler:
11_4 Polosa:
11_5 Cibella:


– RATIONALE: Electronic cigarette nicotine poisonings
(page 50, line 25 to page 51, line 25)

Serious cases of nicotine poisoning are very rare, and the mentioned lethal dose for adults taken orally (60 mg) is based on suspicious self-experiments in the nineteenth century. In light of current knowledge, the oral lethal dose for adults is significantly higher, >500 mg.

12_1 Mayer:


– RATIONALE: Assessment for second-hand exposure: ”Scungio et al. (2018) evaluated the excess lifetime carcinogenic risk (ELCR) of […] second-hand smoke from electronic cigarettes and found about two orders of magnitude of difference between ELCR associated to mainstream aerosol (that were below 1.10-5) and second-hand aerosol.”
(Page 60, lines 16-19).

In the same study it is also mentioned that: ”The corresponding ELCR value of mainstream EC [electronic cigarette] aerosol […] is 5 orders of magnitude lower than that of mainstream traditional cigarettes smoke, and also lower than the guideline values defined by EPA and WHO. Particle number concentrations […] were measured in second-hand aerosol of ECs, leading to extremely low values of ELCR due to the exposure to second-hand EC aerosol.”

10_4 Scungio:


– RATIONALE: 6.6 Role in the initiation of smoking (particularly focusing on young people).
Page 62, line 45 – page 64, line 27.

All sections on the use of e-cigarettes among young people lack information on the regularity of use among young people who have never smoked, which is essential information when evaluating both the health risks of e-cigarette use and its potential addictiveness.

Regular use of e-cigarettes by never-smoking youth is very rare. In the United States, for example, among never-smoking young people regular use of e-cigarettes (≥20 days/month) was 0.4% in 2018, Great Britain 0,1% in 2019 (weekly), Finland 0,4% in 2015 (weekly).

3_3 Glasser:
3_4 ASH:
12_3 Kinnunen:

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