By Dr Farsalinos

I am sure you all remember the story with the research letter published in New England Journal of Medicine, claiming to have found 10-15 times higher formaldehyde levels in e-cigarettes compared to tobacco cigarettes. This letter generated a lot of publicity and worldwide headlines about e-cigarettes being more carcinogenic than tobacco cigarettes. I have commented twice on this study (here and here). Moreover, I published a study showing that high levels of formaldehyde are generated only in dry puff conditions.

However, we did not stop there. Together with Clive Bates we prepared an official letter asking for retraction of the NEJM research letter, with a very detailed presentation of our case using the Code of Conduct of the Committee on Publication Ethics. We considered that this is an important public health issue which should not be handled behind “closed doors”; thus, today the journal Addiction published our letter to the editor presenting in short the case for retraction of the NEJM paper. The letter was accompanied by the full document of the case for retraction as supplementary material. Additionally, 40 academics and experts submitted a letter supporting our case for retraction. The authors of the NEJM letter responded to our Addiction letter, and we provided another response to their comments.

In short, our case for retraction is based on misleading claims made in NEJM letter about cancer risks. We all know that cancer risks from smoking are not attributed to formaldehyde but to a large list of carcinogenic compounds which synergistically result in harm and disease. In reality, formaldehyde is not even associated with lung cancer, the most common form of cancer observed in smokers. Moreover, the authors did not assess whether the laboratory conditions of use were relevant to realistic use patterns. We all know the dry puff phenomenon and there is no reason to expand on that. Another argument was that they did not find any formaldehyde but only formaldehyde hemiacetals, which could in fact protect from formaldehyde exposure. Finally, the presentation of the results in the figure was misleading because they used standard deviation for the tobacco cigarette and standard error of mean for the e-cigarette formaldehyde levels. Had they used standard deviation, they would probably have to present error bars that crossed the zero line, showing that the formaldehyde measurements in e-cigarettes had huge variability.

All the documents are available with free access to the full text. Additionally, Clive Bates prepared two documents summarizing the whole case (here and here).

This is an important public health issue because of the confusion and misinformation created by the NEJM research letter, and the widespread misleading headlines in the news-media which had important implications in the message communicated to the society, especially smokers, about the relative risks of e-cigarette use compared to smoking.