A growing number of severe respiratory illnesses and deaths linked to vaping has sounded the alarm about the use of electronic cigarettes, which were introduced several years ago as a safer alternative to traditional cigarettes. The Centers for Disease Control and Prevention announced recently that it is currently investigating 380 cases of severe lung disease across 36 states, along with seven deaths.
Studies have looked at the impact of e-cigarettes with nicotine, but new research from the University of Pennsylvania and published in the journal Radiology shows that vaping without nicotine can also be detrimental. In the study, nonsmokers who vaped just once showed reduced blood flow and impaired endothelial function in the large (femoral) artery that supplies blood to the thigh and leg.
Alessandra Caporale is a postdoctoral fellow in the radiology department at the University of Pennsylvania’s Perelman School of Medicine. She is also lead author on the study, which was co-authored by Michael C. Langham, Wensheng Guo, Alyssa Johncola, Shampa Chatterjee and Felix W. Wehrli, all with Penn Medicine. Caporale joined the Knowledge at Wharton radio show on SiriusXM to discuss what the study’s findings mean for consumers who use e-cigarettes (Listen to the podcast at the top of this page.)
An edited transcript of the conversation follows.
Knowledge at Wharton: What did your study entail, and what were the findings?
Alessandra Caporale: We wanted to investigate the acute effects of non-nicotinized electronic cigarette vaping on vascular function. We used a non-invasive technique, MRIs or magnetic resonance, and we wanted to see what inhaling these aerosols caused to the endothelium. The endothelium is the innermost layer of the vasculature.
We used an e-cigarette without nicotine, and after a single episode of vaping, we saw that these affected the capacity of the femoral artery to vasodilate.
Knowledge at Wharton: You were able to see an impact after just one use?
Caporale: Yes, it was a transient effect. On a parallel study, we also show that inhalation caused inflammation and oxidative stress that eventually came back to the baseline levels within six hours. So, it’s a transient effect, and this is related to the effect to the vasculature. Because when you inhale the aerosol, the tiny droplets can be translocated or transferred into the bloodstream from the tiny sacs, from the alveoli of your lungs.
“We need to be cautious about associating this highly specific study to what is happening right now.”
Knowledge at Wharton: This was a one-time instance for nonsmokers involved in this study. From the results, can we theorize that, even seeing some recovery after several hours, there is a negative effect from vaping over a longer period of time?
Caporale: Yes, it would be logical to extrapolate that. But we need to be cautious about associating this highly specific study to what is happening right now. There are over 200 cases, but they’re not just cases. They have faces and names: Alexander Mitchell, Maddie Nelson, Kevin Boclair — these are teenagers. A common aspect is that they were vaping. Some of them were also vaping THC, so they were vaping marijuana, and you don’t really know the vaping habits and what they put inside the cartridges.
It is well-known that inside of the aerosol there are some toxic compounds and carcinogenic compounds that can be created by the heating of the liquid, and also the flavorings.
Knowledge at Wharton: Your study used just one vaping product. Would you say that this is really the start of more research in this area?
Caporale: Correct. There is a huge variety of products and a huge variety of liquids, and the problem is that there is no regulation. You can also imagine a black market with counterfeiters, so they are putting on the market probably some unknown concoctions. We really need more investigation and more regulation.
Knowledge at Wharton: Do the results from your study indicate that there could be more long-term impact on blood vessels, such as hardening of the arteries, as people vape habitually?
Caporale: Yes. The fact that the endothelium doesn’t work very well is commonly, universally known as being the first step towards the pathogenesis of cardiovascular disease. On the long-term, if repeated multiple times, you could likely see a harmful effect on your vasculature.
Knowledge at Wharton: When these products were first introduced, they were marketed as a safer alternative to traditional cigarettes, correct?
Caporale: Yes, and it could be true in some cases. Many studies found that some levels of, for example, formaldehyde were lower in the electronic cigarettes compared to the tobacco cigarettes. But if you use the electronic cigarettes at high voltages or high powers, then the likelihood that you release these carcinogens increases. So, it’s generally true. It might be slightly safer. The problem is, you need to consider your usage of it.
Knowledge at Wharton: We know that nicotine has an impact, but we’re also talking about the impact of the aerosol that’s used within these products as well, correct?
Caporale: Yes. It’s known that nicotine worsens the situation. Nicotine accelerates some processes, for example. But even without nicotine — that’s the problem, because the flavors attract young people. They could vape even without nicotine, but that’s not just water vapor. It’s an aerosol, and it’s different.
Knowledge at Wharton: Do blood vessels react differently to vaping compared with, say, a poor diet? Are there elements that are the same?
Caporale: The common aspect would be to increase the risk of cardiovascular disease. Having a bad diet and not doing physical activity, all these things would commonly increase the risk of cardiovascular disease. It means the risk of stroke and heart attack because the vessels are subject to aging. But if you could maintain them as much as possible, that would be the best thing.
“There is a huge variety of products and a huge variety of liquids, and the problem is that there is no regulation.”
Knowledge at Wharton: A lot of people are looking at these studies because vaping products have become a significant business for tobacco companies in the United States and around the world.
Caporale: Of course, tobacco smoking is not safe at all. I just want to point out that I’m not here to say, “OK, we need to come back to tobacco smoking.” The best thing would be just to breathe air, possibly not polluted. But everything you inhale that is not air can be harmful.
Knowledge at Wharton: What reaction have you been receiving to the study?
Caporale: I was personally contacted by people worried because they had quit smoking and started using electronic cigarettes. Also, CBD is very common and is used for medical purposes. But there are some people who are using CBD vape pens, so I would just like to point out more research is needed.
Knowledge at Wharton: As these products were developed, the medical concerns were not tackled at the outset. Are we now playing catch-up in trying to understand the impact of these products?
Caporale: Yes, correct. We need to understand what impact they may have on a large scale and on long-term use.
Knowledge at Wharton: What are the next steps for this research?
Caporale: I’m personally fascinated by the endothelium, so my research would go in this direction to see the long-term impact. That is a question that I would like to answer. I’d like to see other properties of the vessels and how they react to these interactions with the e-cigarette inhalants and with tobacco, as well.
There are studies coming out comparing different products. There are over 8,000 flavors on the market, so they’re also looking at the effects of the different flavorings. Some conclusions were made. For example, it’s known from other studies that the cinnamon flavor is toxic to cells. Also, sometimes what is labeled on the products doesn’t really correspond to what is inside the cartridge.
I would like to underline another aspect, which is the social and psychological impact of these products because I have seen them. At the beginning of this year, the Food and Drug Administration organized a public hearing, and there was an important aspect that was stressed. Some teenagers and middle school kids start vaping and start using e-cigarettes to be accepted by the group. It is a current trend. If you go on YouTube, you can find many videos of these kids vaping to prove something, probably. This is another aspect that is worth noting.
Knowledge at Wharton: What else will future research in this area examine?
Caporale: There have been studies also on air pollution, and the problem here is the ultra-fine particles. They are so tiny that they can reach the brain. There are several mechanisms. For example, they could pass what is called the blood-brain barrier, or they could reach the brain through the olfactory nerve. Once inside the brain vasculature, they promote inflammation and oxidative stress. Inflammation was associated with the development of neurodegenerative diseases.
Knowledge at Wharton: Is there greater risk for young people?
Caporale: Yes, these are developing brains. And there is not just the impact of ultra-fine particles, but also the impact of nicotine. Some of these products contain a high dose of nicotine. This is important, too, because some teenagers are not aware that their intake of nicotine is so high. They get hooked by nicotine addiction before they can even notice it.
Knowledge at Wharton: What is the message that you hope is delivered from this research?
Caporale: That parents should be warned and should warn, in turn, their children. There is no need to vape to be cool or to be accepted. And these products need more regulation.
