There are many hundreds of websites where vaping advocates promote research papers and reports with findings and conclusions which are compatible with their goals. This page provides links to important findings and reviews which are inconvenient to those interest groups’ objectives. Click the headings below to go to the reports
A very long list of health agencies and expert bodies around the world which do not recommend nicotine vaping products for smoking cessation or harm reduction.
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Respiratory, cardiovascular & other disease
EXPLOSIONS (see this compilation video)
REVIEW Seitz CM, Kabir Z. Burn injuries caused by e-cigarette explosions: A systematic review of published cases. Tob Prev Cessation 2018;4(September):32
US Fire Administration (FEMA).Electronic cigarette fires and explosions in the United States 2009 – 2016. July 2017 “Between January 2009 and December 31, 2016, 195 separate incidents of explosion and fire involving an electronic cigarette were reported by the U.S. media. These incidents resulted in 133 acute injuries. Of these injuries, 38 (29 percent) were severe.”
FLAVOURS
Flavor and Extract Manufacturers Association of the United States (FEMA). The Safety Assessment and Regulatory Authority to Use Flavors: Focus on E-Cigarettes. 2021 (“E-cigarette manufacturers should not represent or suggest that the flavor ingredients used in their products are safe because they have FEMA GRAS status for use in food because such statements are false and misleading“)
OVERVIEWS, MAJOR REPORTS
REVIEW Banks E et al. Health impacts of electronic cigarettes. National Centre for Population Epidemiology and Population Health, Australian National University 2022
RESPIRATORY, CARDIOVASCULAR & OTHER DISEASE
REVIEW Siddiqi TJ et al. Association of electronic cigarette exposure on cardiovascular health: a systematic review and meta-analysis. Current Probl Cardiology 2023 “Overall, 27 studies (n=863) were included. Heart rate increased significantly after acute EC exposure (weighted mean difference [WMD]: 0.76 bpm; 95% confidence interval [CI], 0.48, 1.03; p<0.00001; I2=92%). Significant increases in systolic blood pressure (WMD: 0.28 mmHg; 95% CI, 0.06, 0.51; p=0.01; I2=94%), diastolic blood pressure (WMD: 0.38 mmHg; 95% CI, 0.16, 0.60; p=0.0006; I2=90%), and PWV (WMD: 0.38; 95% CI, 0.13, 0.63; p=0.003; I2=100%) were also observed. … Our results demonstrate that smoking EC is associated with a significant increase in cardiovascular hemodynamic measures and biomarkers.“
REVIEW Braken-Clarke et al Vaping and lung cancer – A review of current data and recommendations, Lung Cancer 2023 “E-cigarette devices and vaping fluids demonstrably contain a series of both definite and probable oncogens including nicotine derivatives (e.g. nitrosnornicotine, nitrosamine ketone), polycyclic aromatic hydrocarbons, heavy metals (including organometal compounds) and aldehydes/other complex organic compounds. These arise both as constituents of the e-liquid (with many aldehydes and other complex organics used as flavourings) and as a result of pyrolysis/complex organic reactions in the electronic cigarette device (including unequivocal carcinogens such as formaldehyde – formed from pyrolysis of glycerol). Various studies demonstrate in vitro transforming and cytotoxic activity of these derivatives … there is clear reason for concern regarding the potential oncogenicity of E-Cigarettes/E-Liquids with a strong basic and molecular science basis. Given lag times (extrapolating from tobacco smoke data) of perhaps 20 years, this may have significant future public health implications.”
REVIEW Park et al Vaping and lung inflammation and injury. Ann Rev Physiology 2022 “In this comprehensive review, we discuss the diverse spectrum of vaping exposures, epidemiological and clinical reports, and experimental findings to provide a better understanding of EVALI and the adverse health effects of chronic e-cigarette exposure“
STATE OF THE ART REVIEW Jonas A. Impact of vaping on respiratory health. BMJ 2022
SYSTEMATIC REVIEW Chand BR, Hosseinzadeh H. Association between e-cigarette use and asthma: A systematic review and meta-analysis. J Asthma 2021 https://doi.org/10.1080/02770903.2021.1971703 “Pooled analysis found a significant association between current e-cigarette use and asthma (pOR =1.36, 95% CI 1.21-1.52) and ever e-cigarette use and asthma (pOR =1.24 95% CI 1.13-1.36).”
REVIEW Keith R, Bhatnager A. Cardiorespiratory and immunologic effects of electronic cigarettes. Current Addiction Reports 2021 8:336–346 (“The use of e-cigarettes in humans is associated with significant adverse cardiorespiratory and immunological changes. Data from animal models and in vitro studies support the notion that long-term use of e-cigarettes may pose significant health risks.”)
REVIEW Tsai M, Byun MK, Shin J, Alexander LEC. Symposium Review: Effects of e-cigarettes and vaping devices on cardiac and pulmonary physiology J Physiol 2020;588(22): 5039–5062 (“Research thus far demonstrates that the heart and lung undergo numerous changes in response to e-cigarette use,and disease development will depend on how those changes combine with both environmental and genetic factors.E-cigarettes have been advertised as a healthy alternative to cigarette smoking, and users are under the impression that vaping of e-cigarettes is harmless, but these claims that e-cigarettes are safer and healthier are not based on evidence. Data from both humans and animal models are consistent in demonstrating that vaping of e-cigarettes causes health effects both similar to and disparate from those of cigarette smoking.“)
Wehrli FW et al. New insights from MRI and cell biology Into the acute vascular-metabolic implications of electronic cigarette vaping. Frontiers in Physiology 21 May 2020 (“The acute effects observed following a single vaping episode persist for 1–3 h before subsiding to baseline and are paralleled by build-up of biological markers. Sparse data exist on long-term effects of vaping, and it is likely that repeated regular exposure to e-cig aerosol during vaping will lead to chronic conditions since there would be no return to baseline conditions as in the case of an isolated vaping episode.”)
SECONDHAND VAPING
Soule EK, Maloney SF, Spindle TR et al. Electronic cigarette use and indoor air quality in a natural setting. Tob Control 2017;26:109-112 (PM2.5 concentrations observed at an e-cig vaping event with 59-86 vapers present were higher than concentrations reported previously in hookah cafés and bars that allow cigarette smoking)
Fuoco FC et al. Influential parameters on particle concentration and size distribution in the mainstream of e-cigarettes. Environ Poll 2014 Jan;184:523-9. “Different types of electronic cigarettes, liquid flavors, liquid nicotine contents, as well as different puffing times were tested. Conventional tobacco cigarettes were also investigated. The total particle number concentration peak (for 2-s puff), averaged across the different electronic cigarette types and liquids, was measured equal to 4.39 ± 0.42 × 10(9) part. cm(-3), then comparable to the conventional cigarette one (3.14 ± 0.61 × 10(9) part. cm(-3)). Particle number distribution modes of the electronic cigarette-generated aerosol were in the 120-165 nm range, then similar to the conventional cigarette“
SMOKING CESSATION
16 Reviews of cessation evidence published since 2017
(2021) Wang, Bhadriraju & Glantz E-Cigarette Use and Adult Cigarette Smoking Cessation: A Meta-Analysis. Am J Public Health “We identified 64 papers (55 observational studies and 9 randomized clinical trials [RCTs]). In observational studies of all adult smokers (odds ratio [OR] = 0.947; 95% confidence interval [CI] = 0.772, 1.160) and smokers motivated to quit smoking (OR = 0.851; 95% CI = 0.684, 1.057), e-cigarette consumer product use was not associated with quitting. Daily e-cigarette use was associated with more quitting (OR = 1.529; 95% CI = 1.158, 2.019) and less-than-daily use was associated with less quitting (OR = 0.514; 95% CI = 0.402, 0.665). The RCTs that compared quitting among smokers who were provided e-cigarettes to smokers with conventional therapy found e-cigarette use was associated with more quitting (relative risk = 1.555; 95% CI = 1.173, 2.061).Conclusions. As consumer products, in observational studies, e-cigarettes were not associated with increased smoking cessation in the adult population. In RCTs, provision of free e-cigarettes as a therapeutic intervention was associated with increased smoking cessation.Public Health Implications. E-cigarettes should not be approved as consumer products but may warrant consideration as a prescription therapy.“
(2021) Pound, Zhang et al .Smoking cessation in individuals who use vaping as compared with traditional nicotine replacement therapies: a systematic review and meta-analysis. BMJ Open “We found no difference in smoking cessation, harms and smoking reduction between e-cigarette and NRT users. However, the quality of the evidence was low. Further research is needed before widespread recommendations are made with regard to the use of ENDS.”
(2021) World Health Organization: ”To date, evidence on the use of ENDS as a cessation aid is inconclusive.” (World Health Organization 2021)
(2021) US Preventive Health Services Taskforce: “The USPHSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of e-cigarettes for tobacco cessation in adults.”
(2021) World Health Organization’s WHO study group on tobacco product regulation (TOBREG): “There is insufficient evidence that HTPs (heated tobacco products) aid a switch from smoking. Therefore, claims should not be made to that effect. Even if future evidence supported HTPs as effective switching aids (i.e. substituting one tobacco product for another), they should never be considered as treatment for smoking cessation, which includes quitting nicotine use.”
(2020) European Commission’s Scientific Committee on Health, Environmental and Emerging Risks ”there is weak evidence for the support of electronic cigarettes’ effectiveness in helping smokers to quit”
(2020) United States Surgeon General report on smoking cessation “there is presently inadequate evidence to conclude that e-cigarettes, in general, increase smoking cessation.”
(2020) Ireland’s Health Research Board “there is no evidence of a difference in effect on incidences of smoking cessation. There is a low-level of certainty in these results due to low successful event rates and high rates lost to follow-up in all studies”.
(2020) Australian National University Review for Commonwealth Department of Health (preliminary report) (“there is insufficient evidence that nicotine-delivering e-cigarettes are efficacious for smoking cessation, compared to no intervention, placebo existing nicotine-replacement therapy or other best-practice interventions.”
(2020) Thoracic Society of Australia and New Zealand “Smokers who enquire about using e‐cigarettes as a cessation aid should be provided with appropriate information about approved medication in conjunction with behavioural support (as these have the strongest evidence of efficacy to date). E‐cigarettes are not the first‐line treatment for smoking cessation.”
(2020) Grebovac et al (Effectiveness of Electronic Cigarettes in Smoking Cessation: a Systematic Review and Meta-Analysis) “nicotine-ECs may be more effective in smoking cessation when compared to placebo ECs or NRT. When compared to counselling alone, nicotine ECs are more effective short-term but its effectiveness appears to diminish with later follow-ups. Given the small number of studies, heterogeneous design and the overall moderate to low quality of evidence, it is not possible to offer clear recommendations.”
(2019) European Respiratory Society “There is not enough scientific evidence to support e-cigs as an aid to smoking cessation “
(2018) US National Academies of Science, Engineering and Medicine — a “review of reviews”. (“Conclusion 17-1. Overall, there is limited evidence that e-cigarettes may be effective aids to promote smoking cessation.”)
(2018) European Public Health Association (“e-cigarettes may help some smokers quit but, for most, e-cigarettes depress quitting”)
(2018) CSIRO “There is currently no evidence that quit rates for smoking have decreased as a result of e-cigarette use. Long-term success with cessation was not measured in trials.”
(2017) El Dib et al A systematic review and meta-analysis three RCTs and nine cohort studies concluded: “There is very limited evidence regarding the impact of [e-cigarettes] on tobacco smoking cessation, reduction or adverse effects: data from RCTs are of low certainty and observational studies of very low certainty. The limitations of the cohort studies led us to a rating of very low-certainty evidence from which no credible inferences can be drawn.”
Other important cessation evidence
Kaplan B et al. Effectiveness of ENDS, NRT and medication for smoking cessation among cigarette-only users: a longitudinal analysis of PATH Study wave 3 (2015-2016) and 4 (2016-2017), adult data. Tobacco Control 2021 Sep 15;tobaccocontrol-2020-056448. doi: 10.1136/tobaccocontrol-2020-056448. “None of the cigarette-only users who used ENDS (ecigs) to quit smoking became ENDS-only users in wave 4; 37.6% became dual users of ENDS and cigarettes … No differences were found when cessation rates of ENDS, NRT or non-NRT medication were compared.”
Xia W et al. The association between heated tobacco product use and cigarette cessation outcomes among youth smokers: A prospective cohort study. J Subst Abuse Treat. 2021 Aug 15 “7-day point prevalence of cigarette absence was statistically significantly lower among heated tobacco product users than among non-HTP users after 6 months (19.0% vs. 34.2%) … Youth HTP users were less likely to abstain from tobacco use than their non-HTP-using counterparts.”
Greenhalgh, EM, & Scollo, MM. 18B.6 Effects of e-cigarette use on smoking. In Greenhalgh, EM, Scollo, MM and Winstanley, MH [eds]. Tobacco in Australia: Facts and issues. Melbourne: Cancer Council Victoria; 2022.
TOXICITY
Gordon T et al. E-cigarette toxicity. Annu Rev Pharmacol Toxicol. 2022 January 06; 62: 301–322. doi:10.1146/annurev-
pharmtox-042921-084202.
WHO study group on tobacco product regulation: Report on the scientific basis of tobacco product regulation: eighth report of a WHO study group May 2021 334pp
Eshraghian EA, Al-Delaimy WK. A review of constituents identified in e-cigarette liquids and aerosols. Tob. Prev. Cessation 2021;7:10. “[there were] 60 compounds in e-liquids and 47 compounds in aerosols. A total of 22 compounds were identified in both e-liquids and aerosols. These are: acenaphthylene, acetaldehyde, acetol, antimony, benzaldehyde, benzene, chromium, copper, diacetyl, formaldehyde, glycerol, lead, limonene, naphthalene, nickel, nicotine, nicotine-N’-oxides, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), N-Nitrosonornicotine (NNN), propylene glycol, toluene, and vegetable glycerin. Some of the identified chemicals have been labeled as harmful, toxic, or cancerous through human, animal, and cell line studies.”
Committee on Toxicity of Chemicals in Food, Consumer Products an Environment (COT). Statement on the potential toxicological risks from electronic nicotine (and non-nicotine) delivery systems (E(N)NDS – e-cigarettes) UK, 2020 [“The use of E(N)NDS products, produced according to appropriate manufacturing standards and used as recommended, as a replacement for CC smoking, is likely to be associated with a reduction in overall risk of adverse health effects, although the magnitude of the decrease will depend on the effect in question. Uptake of E(N)NDS product use de novo by non-users of tobacco products is likely to be associated with some adverse health effects to which the user would not otherwise have been subject. The use of a wide range of flavouring products in eliquids, for which data on toxicity by inhalation, particularly of any thermally-derived products, are generally not available, is an area of uncertainty. While there is currently no information that this is leading to adverse effects on human health, this is an important data gap.“]
YOUTH UPTAKE
Yoong S et al. Prevalence of electronic nicotine delivery systems and electronic non-nicotine delivery systems in children and adolescents: a systematic review and meta-analysis. Lancet 2021
The most recent prevalence data from 26 national surveys representing 69 countries and territories, with a median sample size of 3925. Mean pooled prevalence for ever vaping =17.2% (1 in 5.8) and vaped in last 30 days = 7.8% (1 in 12.8).
Staff J, Kelly BC, Maggs JL, Vuolo M. Adolescent electronic cigarette use and tobacco smoking in the Millennium Cohort Study. Addiction 2021 [“Among youth who had not smoked tobacco by age 14 (n = 9046), logistic regressions estimated that teenagers who used e-cigarettes by age 14 compared with non-e-cigarette users, had more than five times higher odds of initiating tobacco smoking by age 17 and nearly triple the odds of being a frequent tobacco smoker at age 17 , net of risk factors and demographics.“]
Simon Chapman AO 