Evidence submitted to the FDA concerning electronic cigarettes


Evidence submitted to the FDA concerning electronic cigarettes


By Dr Farsalinos

Today, I submitted a comment to the FDA, presenting the paper: Farsalinos K.E., Polosa R. Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarettes substitutes: A systematic review. Ther Adv Drug Saf 2014;5:67-86.

This is the systematic literature review on safety/risk profile of electronic cigarettes as tobacco cigarette substitutes that was published few months ago. You can see the submitted comment below.




Comment Submitted in Response to FDA Regarding Proposed Rule Deeming Tobacco Products to be Subject to the Federal Food, Drug, and Cosmetic Act, as Amended by the Family Smoking Prevention and Tobacco Control Act; Regulations on the Sale and Distribution of Tobacco Products and Required Warning Statements for Tobacco Products


Konstantinos Farsalinos, MD

Onassis Cardiac Surgery Center, Kallithea, Greece

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Riccardo Polosa, MD, PhD

Centro per la Prevenzione e Cura del Tabagismo, Institute of

Internal Medicine, Azienda Policlinico-V Emanuele, Dipartimento di Biomedicina

Clinica e Molecolare, Universita di Catania, Catania, Italy

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Comment Tracking Number: 1jy-8do7-pcm4


We are submitting our recent review of the scientific evidence on safety evaluation and risk assessment of electronic cigarettes as tobacco cigarette substitutes, for the FDA's consideration.


Farsalinos K.E., Polosa R. Safety evaluation and risk assessment of electronic cigarettes as tobacco cigarettes substitutes: A systematic review. Ther Adv Drug Saf 2014;5:67-86.


This is a peer reviewed systematic literature review, published in Therapeutic Advances in Drug Safety, which evaluates all the evidence on safety and risk associated with electronic cigarette use. Of note, the authors of this review are actively involved in electronic cigarette research and are listed as the most productive scientists in terms of number of publications on this issue in peer-reviewed journals (Zyoud et al. Worldwide research productivity in the field of electronic cigarette: a

bibliometric analysis. BMC Public Health 2014;14:667.)

Although the research and knowledge on electronic cigarettes is continuously expanding, there is sufficient evidence to support that they are by far less harmful compared to tobacco cigarettes and that switching from tobacco cigarette to electronic cigarette use is expected to result in significant health benefits for smokers.


The main points of this review are:

  • ·         Electronic cigarette deliver an aerosol to the user (which may contain nicotine) without involving combustion.
  • ·         Nicotine is not officially listed as a carcinogen, is not causing respiratory disease and has minimal effects in initiating and propagating atherosclerosis. Despite laboratory evidence that nicotine may exhibit carcinogenic and mutagenic effects, no clinical study has ever confirmed that it has such properties at levels associated with human use. It is well-known that smokers smoke for nicotine but die from combustion products.
  • ·         Most of the chemicals emitted in tobacco cigarette smoke are completely absent from electronic cigarettes, or are present in minimal quantities. A characteristic example is tobacco-specific nitrosamines, with smoking resulting in up to 1800 times higher daily exposure compared to electronic cigarette use. No combustion products are emitted from electronic cigarettes. Other toxic chemicals such as carbonyls are emitted at levels lower by order(s) of magnitude compared to tobacco products. The chemical profile of electronic cigarette liquids and aerosol is perfectly compatible with their role as tobacco harm reduction products.
  • ·         The studies evaluating particle size have been mispresented as showing evidence of risk for cardiovascular and respiratory disease. In reality it is scientifically unprecedented to discuss about size and ignore the composition of the particles. Electronic cigarette aerosol is mostly comprised of droplets of propylene glycol, glycerol, nicotine and flavorings, with minimal quantities of other chemicals. They are incomparable to micro- and nano-particles emitted from combustion sources (such as tobacco cigarettes) or to environmental pollution particulate matter. There is no evidence that the particles emitted from electronic cigarettes represent a risk factor for cardiovascular disease. Based on their composition, they confer minimum (if any) risk.
  • ·         All cytotoxicity studies of electronic cigarette aerosol have found that electronic cigarettes have minimal, and in some cases no, cytotoxic properties on cultured cells. The comparison with tobacco cigarette smoke confirmed that electronic cigarettes are by far less toxic to the cells studied. Animal studies have verified the beneficial safety profile of the basic electronic cigarette ingredients (propylene glycol, glycerol and nicotine) compared to tobacco cigarette smoke.
  • ·         There is no second-hand exposure to combustion products. Exposure to nicotine is at levels 10 times lower than tobacco cigarettes. Of note, second-hand exposure to nicotine is not associated with addiction or other adverse health implications. One study found the release of polycyclic aromatic hydrocarbons; however, the finding is questionable due to the lack of combustion in electronic cigarettes.
  • ·         Clinical studies have shown that electronic cigarette use is not associated with acute worsening of cardiac function or coronary flow disturbances and does not activate inflammatory pathways. There are mixed findings concerning the acute effects on respiratory function. No study has found worsening of spirometry measurements, while a study comparing active and passive smoking with electronic cigarette use found adverse effects only after smoking. Of note, a recent study (not included in the review because it was published later) found asthmatic smokers who switch to electronic cigarette use show significant improvement in respiratory function after 1 year of electronic cigarette use (Polosa et al. Effect of smoking abstinence and reduction in asthmatic smokers switching to electronic cigarettes: evidence for harm reversal. Int J Environm Res Public Health 2014;11:4965-4977).


Current evidence overwhelmingly supports that electronic cigarettes are by a large margin less harmful compared to tobacco cigarettes. Every regulatory decision should be based on scientific evidence. Although long-term studies are needed to accurately evaluate the magnitude of risk-reduction, this should be examined through post-marketing surveillance, as is the case for every other consumer product and even for medications.



We have attached the pdf file of the published review.




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