Professor Polosa has recently completed his latest study, a review of the effect of vaping on respiratory health. We got together with Riccardo Polosa to discuss how vaping can reverse harm, the potential to reduce infections, the latest controversy over vaping and respiratory diseases in the US and more.
In a recent press release you reiterated that vaping is at least to be 95% safer than smoking, and probably even safer than 95%. As you’ve also said, no-one can prove e-cigarettes are 100% safe because we don’t have very long term data. How confident can we be of the 95% safer figure?
Public Health England reiterated this finding in their evidence update from last year (2018). Stating that vaping is at least 95% less harmful than smoking remains a good way to communicate the large difference in relative risk based on current toxicological evidence. It has been repeatedly shown that vape aerosol contains far fewer toxins found compared to cigarette smoke and – just as important – the levels of those toxins detected in vape aerosol were substantially lower than in tobacco smoke, often several orders of magnitude lower (10 times lower).
In your study you mention the need for long term studies based on an analysis of medical records. How close are we to being able to achieve this?
The collection of patient records varies widely between countries. In addition, patient records must report if a person is vaping, how much, and for how long, and include the same information on smoking or other tobacco use. This may be available currently or in the near future in some countries, but will never be possible for others.
Research based on access to medical records is challenging due to ethics and privacy concerns, but where the reports are available, the studies can provide a key to understanding the long-term effects of vaping. Another way we can check on the long-term effects of vaping is through the science of epidemiology. As fewer people smoke cigarettes, over time we expect to see a reduction in tobacco-related diseases (respiratory, cardiovascular, and cancers). Using mathematics, we can apply population estimates of the number of vapers to the number of reports of smoking-related diseases to observe the correlations.
You also talked about the need for studies looking at the effect of vaping on people who have never smoked, in order to separate negative effects of vaping from existing harms caused by smoking. Given the low number of non-smokers who regularly vape, how easy is it to find these people, and how realistic would it be to conduct a large scale study?
Vapers who never smoked regularly are the proverbial needle in the haystack. Nonetheless, well-coordinated multi-national efforts may gather study populations that are large enough to answer important research questions about the long-term health effects of vaping. This is the only way to go. We are lucky enough that we have been awarded a generous research grant from the Foundation for a Smoke Free World to accomplish just that.
Your previous research has suggested that electronic cigarettes can help to reverse some smoking diseases.
It’s particularly interesting to see in this review that smokers suffering from COPD experienced an improvement in health when at the same time smokers who quit smoking often don’t experience an improvement. Why do you think this is the case?
Simple. When interpreting these studies, it is important to understand the distinction between smokers who quit and with a smoking-related disease and quitters who do not have (or have not yet developed) any medical conditions. It is relatively easy to show improvements in quitters who have an abnormal baseline (they have already caused damage to their health by smoking) – and this is what I call harm reversal. On the contrary, relatively healthy smokers have already a normal/healthy baseline, so there is no room for improvement. The benefit for relatively healthy smokers stands in the ability of quitting at reducing their risk of developing a smoking-related disease in future – and this is risk reduction.
To what extent do you think anti-bacterial and anti-viral properties of propylene glycol in e-liquid could benefit vapers?
PG in aerosol form has been long known as an effective antibacterial and antiviral agent and likely to efficiently preventing infections of the respiratory tract. Therefore, far from creating an ideal condition for germs to multiply and spread, PG vaping can help users fight off all sorts of bacteria, viruses and common infections (e.g. colds, tonsillitis, gingivitis). Moreover, daily vaping could be a practical way to prevent respiratory exacerbations associated with diseases such as asthma and COPD.
As you’ve mentioned in the article, technology is contributing to an improvement in the safety of vaping devices, mentioning in particular automatic temperature control. To further improve the safety of vaping, where should manufacturers concentrate their efforts?
Temperature regulation is very important. But it is just one aspect of technological improvement in e-cigarette design. Manufacturers should invest in new generation batteries that can provide the power in the safest manner possible and develop new formulations that can guarantee maximum satisfaction with less chemicals. Ease of refilling, as well as ease of use in general, are important features. Public concerns over plastics and recycling should be another area for improvements, particularly for pods and other pre-filled devices.
In the UK over the last few years, there has been a lot of effort to improve the safety of e-liquid by identifying potentially harmful ingredients in e-liquid and eliminating them. How much can this work contribute towards improving the safety of vaping?
Different flavours have different chemical profiles, and therefore different levels of toxicity. Vapers should have the assurance that the liquids have been tested and conform to current quality/safety guidelines. Concerns about poor quality/safety products are currently being addressed by the Technical Committee of the European Standardization body for e-cigarettes and e-liquids (CEN TC437).
However, when looking at top priority for safer vaping, careful toxicological characterization and risk assessment of flavours in vape aerosols comes immediately to my mind. We have recently circulated a revised draft proposal of the study aiming at creating a toxicological database of common commercially available flavours, and possibly identify upper limit thresholds for the use of specific ingredients. The aerosols will be tested using “cell on chip” technology, a more affordable method of understanding the toxicological impact of flavours in vitro.
Your review of the literature at times seems to be a catalogue of errors by researchers. These include exposing animals to far higher concentrations of e-cigarette emissions than that of cigarette emissions in comparative tests, not adjusting for the weight of animals used in research, and not using a control group. Why are there so many issues with the studies being carried out into electronic cigarettes? Is this simply due to poor standards, or are standards being deliberately manipulated to support a desired outcome?
No manipulation here. Vapour product research is fairly new, and so researchers have had to make their own judgements on proper testing. As a consequence of this, many of the research designs have not been adequate or based on pharmaceutical testing where overdosing is a common procedure.
In addition, when researching the impact of real-world interventions and epidemiology, conventional study designs are not fit- for-purpose and it is difficult to reconcile more appropriate study designs with good scientific principles. Last but not least, sometimes the problem is a lack of adequate funding for testing equipment, so the researchers use whatever they have available, even if it is less valid or reliable. It goes without saying that this research field is in need of urgent critical review and reform.
You also mentioned some encouraging initiatives to standardise research methods in the field of electronic cigarettes. Do you think the appetite to adopt these exists across the field?
Absolutely. For example, the ISO (International Standards Organization) is creating testing standards for vaping machines and for the analytical chemistry of vape aerosols constituents. In addition, besides the one just published and addressing the quality of research in the respiratory field, we are about to conduct a series of reviews of the quality of research techniques.
By discussing the problems and flaws with a large number of current research articles in the field, we intend to draft a set of guidelines and framework for improved quality in tobacco and vaping research. It is envisaged that the framework will be utilized by journal editors as a code of best practice or checklist for future research articles. Researchers want to be utilizing the best practices.
We’ve seen recent reports of vaping seizures in the US and the UK. In the UK it has been clear that these have been due to vaping illicit drugs, but this has been less clear in the US. What’s behind these seizures, how concerning are they and how do they tarry with the findings of your research?
Surprisingly very little research has been done on nicotine use and seizures in humans, either with tobacco or vapes. Animal studies are not applicable to humans in this case. The US reports do not document the substance(s) which these people were vaping, and the awareness of vaping other drugs appears low in the US (and elsewhere). Self-report in the US of illegal drug vaping may be low as disclosure could result in arrest or denial of payment for emergency services. Where clusters of seizure reports occur, it suggests a common source. In addition, no other adverse effects registries have reported an increased occurrence of seizures.
Finally, what would you say to a smoker who is considering switching to vaping, but is concerned by media reports of the dangers of vaping?
The media’s job is to make headlines and stories. Your need is good information. You have a right to know that vaping is far less toxic than smoking. Public Health England has put a lot of research into its findings that e-cigs are far less harmful. It is generally accepted in the research community that e-cigs are substantially less toxic than continuing to smoke.
I would add that to get the most risk reduction, a vaper should completely stop smoking as soon as she/he reasonably can. As we know in harm reduction, substitution is easier to achieve than abstinence. Even smoking 2 or 3 cigarettes a day still carries about half of the risk for cancer that comes from smoking 20 cigarettes a day.
I would add that vapers should vape with moderation and stress that extreme form of vaping (e.g. cloud chasing, excessive daily consumption of e-liquid) should be avoided because of the increase in potential health and safety risks.
Polosa R, New Review Suggests Normal Use of Electronic Cigarettes is Unlikely to Raise Significant Health Concerns, Aug 2019, PR Newswire
Polosa R, O’ Leary R et al, The effect of e-cigarette aerosol emissions on respiratory health: a narrative review, 2019 Expert Review of Respiratory Medicine, DOI: 10.1080/17476348.2019.1649146