Two studies conducted by the Duke and Yale Universities in the US, claimed that flavours combine with solvents in e-cigarettes to produce new toxic chemicals that irritate the airways, leading to respiratory and cardiovascular problems. The findings were presented at the ‘virtual’ European Respiratory Society International Congress.

Sven-Eric Jordt, associate professor of anesthesiology, pharmacology, and cancer biology at Duke University School of Medicine in North Carolina, said that while e-cig manufacturers say that vapes are safe and chemically stable, the mixture of some components makes them toxic.

“Our co-author and analytical chemist Dr. Hanno Erythropel and colleagues at Yale University found new chemicals in e-liquids and revealed that they are formed when components are mixed by manufacturers. We became concerned about the high levels of these new compounds that had not been studied in the past, and decided to conduct toxicological tests,” said Prof Jordt.

The studies looked at how flavour compounds reacted with main solvents in e-cigs

The researchers looked at what happened when cells that line the bronchi (the main airways from the trachea to the lungs) were exposed to chemicals used in flavours such as vanillin and ethyl-vanillin (responsible for vanilla and other sweet flavours), benzaldehyde (berry or fruit flavour) and cinnamaldehyde (cinnamon flavour). Then they analysed how these chemicals react when combined with the solvents propylene glycol (PG) and vegetable glycerine (VG), which are the main solvents in e-cigarette liquids.

“The bronchi are exposed to e-cigarette vapor when the user inhales them into the lungs,” said Prof Jordt. “We consistently observed that the new chemicals formed from the flavors and e-liquid solvents were more toxic than either of their parent compounds. The new chemicals derived from benzaldehyde and cinnamaldehyde were more toxic than the vanillin-derived compounds.”

Duke’s Research Center is financed by Big Tobacco

However, Italy’s national vapers association, the ANPVU, is pointing out that the Duke’s Research Center is financed by tobacco multinational, and therefore the study should be withdrawn on grounds of conflict of interest. A press release by the association offers the following clarifications on the claims made by the study:

“ROME, September 5, 2020 – Too many errors and manipulations in the scientific article reported by some Italian newspapers that reveals the prejudice towards the electronic cigarette.

 The premise: the news that the vapors of the electronic cigarette contain irritants caused by the mixing of some aromas with glycol and glycerin, the main diluents contained in refill liquids. The research was conducted by the universities of Yale and Duke. It will be officially presented at the European Respiratory Society congress

 Consumer protection first of all – “The attention to consumer protection is such that just a few months ago ETHRA and ANPVU (the Italian arm of consumers of electronic cigarettes) were called upon to participate in the revision of the existing TDP Directive, in light of the latest scientific discoveries ”underlines Carmine Canino, President of ANPVU.

 Let’s briefly summarize the critical points:

– The titles speak of liquids in general that would create new toxic compounds while on a careful reading it emerges that the study speaks of ‘toxic substances created by the mixing of three aromas in particular’ (vanilla, red fruits and cinnamon) with the diluents of the liquids of refill: glycol and glycerin.

 – On an accurate reading, it is also noted that changes in pressure and heartbeat emerge in ‘subjects predisposed’ to these disorders, central information but not highlighted as it should. The assumption of the study is incorrect. Here is the opinion of Professor Fabio Beatrice, Director of the ENT Department of the San Giovanni Bosco Hospital in Turin and the Nosocomio Anti-Smoking Center: “There is no healthy smoking and therefore no one can claim that electronic smoking is safe. However, it is a viable alternative in selected subjects who are unable to abandon traditional smoking with a view to reducing risk. The study design seems to be done in such a way as to expose ‘predisposed subjects’ to extreme situations to support a thesis. Studies such as these have the serious side effect of causing consumers to relapse into traditional cigarette addiction.

 – The text of the ERS press release reports the statement by Dr. Hanno Erytropel of Yale University stating that ‘high levels of these new compounds have never been studied in the past and we have therefore decided to conduct toxicological tests’. As Alexandre Vedrine, Director of Gaiatrend, one of Europe’s leading e-liquids producers, states: “The issue of chemical compounds in e-liquids is not new and is an integral part of the vision of the best companies on the market. Industry does not discover today. on the contrary, this topic is at a rather advanced stage in his research, just look at the standardization framework for the products of our sector which is being established at European level and which already exists in France.

We know that aromatic molecules combine with each other, interact with glycol and glycerin and nicotine, creating new potentially dangerous or toxic substances by hitting target organs.

 The European Chemicals Agency is very clear on this point: chemical combinations must be analyzed and controlled in both liquid and gaseous phases, and products that do not meet safety criteria and health thresholds proven for the consumer cannot be placed on the market. Our products are tested in human phase 3 clinical studies (ESTxENDS, ECSmoke, VapexpAIR),) by independent researchers.

 – It is written in the ERS press release that ‘the producers have placed the products on the market without any real understanding or control of the basic chemicals’: the study, says the President of ANPVU Carmine Canino, although presented in the context of a prestigious European Congress such as the ERS was conducted on liquids and products on the market in the United States. It is widely known to those involved in the sector that the legislation between the two continents is very different and Europe boasts a very strict legislation called TPD (Tobacco Products Directive) to which everyone must comply.

Confirms the position Sebastien Roux – Chemical Engineer of the Research and Innovation Center for the Crivape vaping who declares: “the producers of liquids for electronic cigarettes, in Europe, are obliged with the TPD to notify the products and declare the carbonyl emissions of which we talk in the studio “.

 – How was the study conducted?- The question that European manufacturers are asking is: what are the machines used to reproduce the vaporization protocol as well as the materials related to the trapping of substances in the vapor of electronic cigarettes?

These techniques are extremely complex and specific, there are only about fifteen laboratories to have developed this technique, to master it and to continue to evolve it.

Dr Roux continues: “To date we have not seen any of the authors and / or organizations linked to this group use these techniques”.

 – The nasty surprise – says Carmine Canino: “when we read the news in the press we would have liked to congratulate the attention that the scientific world pays to the health of consumers of electronic devices and ask that research, clinics, consumers and industry join forces with example by creating a data sharing platform. But the cold shower soon came: The press release contains statements from the first signatory, Professor Sven-Eric Jordt, associate professor of anesthesiology, pharmacology and cancer biology at Duke University School of Medicine. A university not new to researching electronic cigarettes and the alleged damage caused by the vaporization of liquids. Too bad that Duke University Medical Center’s research center on nicotine and smoking cessation was created with a $ 15 million grant from a well-known tobacco multinational.

 The appeal to withdraw the study – By statute, the European Respiratory Society defines itself as an independent body aimed at safeguarding public health. Last October, on the occasion of the congress, an amendment was approved that introduces in the statute a ban on the publication of scientific studies funded by electronic cigarette companies and the tobacco industry. ANPVU therefore asks that the research be withdrawn and not presented to the Congress which will take place online from 7 to 9 September.


 Who is ANPVU – The National Association for United Vapers represents one and a half million Italian consumers of personal vaporizers. It is engaged in the dissemination of medical-scientific news and direct experiences on the validity of the use of vaporizers as a means for reducing the damage from combusted smoke. On the Italian territory and internationally, it undertakes to offer support to smokers in the path of cessation of nicotine addiction through the use of personal vaporizers. It is also committed to defending the rights and interests of vapers and to promoting initiatives aimed at promoting knowledge of the means of harm reduction.

 ANPVU is one of the promoters / founders of ETHRA European Tobacco Harm Reduction Advocates, the international network of Consumer Associations through which dialogue with the institutions of the member countries is fostered, to promote the use of vaporizers as a tool for harm reduction and further clarify that public opinion cannot and must not remain unaware of the real effectiveness of these devices in the fight against smoking.”

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