The blog was in response to media stories about a new study which claims e-cigs lead to a restriction in airway passages, published as a press release entitled: Experts warn that e-cigarettes can damage the lungs.While we were complaining, The Electronic Cigarette Trade Industry Association (ECITA), some ecig companies and tobacco harm reduction scientists have been digging into the study - and found some major flaws in it. This blog post draws heavily upon their efforts. Unfortunately, the only published version I am currently able to link to is Professor Siegel's excellent analysis of the study - I'll add more links as I come across them.
Undisclosed Conflict of Interest
Professor Gratzio, the author of the study, has received funding from Pfizer to conduct studies on 'suicide drug' chantix, a drug which has lead to thousands of incidences of suicide, suicidal thoughts, violence and many other negative side effects, and carries a black box warning by the FDA, but which is considered an effective smoking cessation treatment by the Professor.
Pfizer, along with other pharmaceutical companies, produces nicotine cessation products (including Chantix/Champix) which are threatened by the success of e-cigarettes. They have also spent millions funding groups which have attacked the electronic cigarette.Crucially, this conflict of interest was not disclosed, either to the press or in the media abstract.
Neither Published nor Peer Reviewed
The study in question has neither been published nor peer reviewed. There is no written study available, only an abstract which was presented at a conference.What's alarming is that the pre-release of this abstract seems to have been calculated to create maximum waves in the press - before the actual contents of the study have been made available for scientists to analyse!
Mis-Representation of the Study and Unproved Claims
Damage to the Lungs
The study claims that e-cigarettes can temporarily increase airway resistance to the lungs. This does not mean it causes any harm to the lungs.
However, the study has been represented as showing that damage is caused to the lungs.
Professor Michael Siegel has discussed this in depth, pointing out:
A temporary increase in airway resistance does not equate to "lung damage."Hot humid air also increases airway resistance - but air has not yet been found to damage lungs. (Hopefully, the MHRA and FDA will not attempt to ban humid air!)
Starving Lungs of Oxygen
Claims have also been made that the change in airway resistance leads to lower levels of oxygen in the blood.
In fact, no attempt to measure levels of oxygen in the blood was made, and we do know that humid air does not lead to lower levels of oxygen in the blood!
E-Cigarettes Not Proven SafeThe Professor claimed:
We do not yet know whether unapproved nicotine delivery products, such as e-cigarettes, are safer than normal cigarettes, despite marketing claims that they are less harmful.In contrast to the above claim, the study does not prove that e-cigs are not safe. The claim runs counter to experts' opinions, research and elementary science that shows that 99% or more of the damage of smoking is caused by inhaling the smoke and tar caused by burning tobacco.
Conflicts with Previous Studies
Katherine Devlin of ECITA has queried some of the results of the study.
In particular, in previous research smokers have been found to have a higher airway resistance then never smokers. However, according to the study, smokers have a lower airway resistance than non-smokers.
Professor Siegel also contrasted the results with a previous study into airway resistance, which only found "sub-clinical" changes in airway resistance, and concluded:
the clinical changes may be too small to be of major clinical importance.Professor Polosa, who we interviewed here, also criticised the study in an email to Elaine Keller of the Consumer Advocates for Smoke Free Alternatives Association (CASAA), stating:
A recent clinical safety assessment of one such product in 40 smokers showed that mouth and throat irritation and dry cough were commonly reported in the initial few weeks of use, but all appeared to wane spontaneously by the end of the study, after 24 weeks of regular use. Thus the authors’ conclusions are not fully supported by the data, and the accumulating evidence is rather strongly supportive of a good safety profile for the e-cigarettes.These conflict of results highlights the need for peer review - preferably before conclusions are drawn and published in major newspapers!