Vaping and health: What the evidence tells us

Dr Wendy Winnall

Dr Wendy Winnall is a scientist and scientific communicator with a varied background in research and public health. She holds a Bachelor of Science with a major in genetics, a PhD in immunology and a Masters of Public Health. Over her career as a scientist, she worked in cancer research, reproductive biology and HIV vaccine research, as well as studying the toxic chemicals in tobacco smoke. As a communicator, she is widely experienced in translating complex health information into accessible content, particularly around the health effects of tobacco and vaping, helping to inform policy and educate the public. 

• Further reading: Tobacco in Australia Facts and Issues 18.6 The health effects of e-cigarette use
• Podcast: The Importance of Smoking and Vaping Cessation in Pregnancy and Breastfeeding, with Hao Vo-Tran
• Podcast: The Reality of Youth Vaping and How to Support Young People to Quit, with Dr Moya Vandeleur
• Electronic cigarette use after smoking cessation and lung cancer risk
• Tobacco in Australia Facts and Issues
• Dr Wendy Winnall: LinkedIn
• Refer to Quitline
• Subscribe to Quit Centre's newsletter
• Quit
• My QuitBuddy App
• Cancer Council Victoria

[00:00:00] Paulette: This Quit Insights clinical series podcast is recorded on Wurundjeri Woi-Wurrung Country. We acknowledge the traditional custodians and pay our respects to elders past and present, and we extend that respect to those on the lands where you're listening today. This podcast is intended for health professionals and is for educational and informational purposes only. The content discussed does not constitute medical, legal or professional advice and should not replace your own clinical judgment. Welcome. I'm Paulette Trevena and this is the Quit Insights Clinical Series podcast for health professionals. Each of our episodes bring you in-depth information and insights from professionals who are experts in smoking and vaping cessation. Our guest today is Doctor Wendy Winnall, who is a scientist and scientific communicator with a varied background in research and public health. She holds a Bachelor of Science with a major in genetics, a PhD in Immunology and a Masters of Public Health. Over her career as a scientist, Wendy has worked in cancer research, reproductive biology, and HIV vaccine research, as well as studying the toxic chemicals in tobacco smoke. As a communicator, she is widely experienced in translating complex health information into accessible content, particularly around the health effects of tobacco and vaping, helping to inform policy and educate the public. Welcome, Wendy, and thank you for being our podcast guest today, and thank you very much.  

So in this episode, we'll be exploring the health effects of vaping. Nicotine dependence is still a significant health issue. Tobacco use has declined over time, but it's still a leading risk factor for disease in Australia. Vape use has stabilised. However, it's still a major health concern, especially in teenagers and young adults. Vapes are now extensively used by people who are not smoking, including those who have never smoked, in particular teenagers and young adults under the age of 30. Many people who smoke are now dual users of conventional cigarettes and vapes. So, Wendy, what do the current stats around vaping tell us?  

[00:02:12] Wendy: Well, it's good news in that the vaping rates are no longer rising. And in fact, in young people they've actually dropped slightly. But the bad news is that there's still a significant proportion of people that are vaping. And this puts them at risk of diseases such as lung disease going into the future. Over the past ten years, vaping rates rose dramatically. Only about 1% of people vaped in 2016, and this peaked at 7% in 2022. But now this has dropped slightly. So currently it's 6%, which is good news. But if we look a little deeper into this data, we can see that there are less people who casually vape like once a week or a few times a month, but people who vape every day, these rates haven't fallen, but at least they've stabilised.  

[00:03:00] Paulette: Right.. Okay. You've talked about youth and vaping there. Which specifically are the groups of people that are most likely to be vaping? Is there a breakdown within that group?  

[00:03:12] Wendy: Vaping is most common in people who are in the lower socio economic group, which is similar to smoking. And it's also most common in people under the age of 25, which is actually the opposite of smoking. It's very encouraging to see a drop in vaping rates for these young people. So in 2022, over 20% of people aged 18 to 24 were regular vapers. But this has gone down now from 20% to 14%. But 14% is still quite high. It's actually more than double the current smoking rate. So this 14% is a large proportion of young people who are at risk of addiction, and whose lungs are exposed to a range of chemicals on a regular basis.  

[00:03:55] Paulette: So is there much evidence about the health effects of vaping yet?  

[00:04:00] Wendy: Yes, there is evidence for the health effects, particularly for short term health effects. There's also evidence of cellular damage that could put people at risk of cancer and other conditions. But the risks of long term disease, such as cancer and cardiovascular diseases, these haven't been quantified yet. This is due to the short time period that people have been vaping. So I think it's worth briefly describing the different types of research that are needed to fully understand the health risks of vaping. For the health effects of smoking, of course, we've had over 70 years of research, so the long term effects of smoking on the body are very well characterised. But we've only just started this journey for vaping. We're about ten years into this research, so there's still a long way to go. What we need to determine is which conditions can be caused by vaping. So to establish causation, there's a range of different types of studies that are done. Epidemiology is the most important but it takes the longest time. Cohort studies are the most useful. These are studies that track people over time into the future, and we use these studies to determine the relative risks of specific conditions for people who vape compared to those who have never vaped. There's a number of large cohort studies that are in progress now, and these will start to reveal the longer term health effects of vaping in the future. And we should get some really solid evidence in the next 5 to 10 years. To build a case for causation, we also ask if there's a dose effect, such as do people who vape more have a greater risk? And we ask whether quitting vaping reduces the risk of disease. So this would be very important information.  

[00:05:42] Paulette: Sure.  

[00:05:43] Wendy: We also look for evidence of the biological mechanisms that underlie disease, how the chemicals in vapes could be causing the pathophysiology. And we look for biomarkers of exposure and biomarkers potential damage in people who vape. And we can use this to predict the risks of disease in the future. Putting all this evidence together is what we do to build an overall case to support the claims that vaping is causing specific conditions, and we can also quantify the extent of the risk. So we could say vaping leads to a two fold risk of certain conditions. So after ten years of research, we've certainly made progress. And we know some of the short term risks, and we can make some predictions as to what are the long term risks. For longer term conditions such as cancer and cardiovascular disease, these can take a long time to develop after a first exposure to chemicals. So a lack of solid evidence for vaping causing these diseases cannot be taken as meaning that vaping is safe. We'll only really know the full extent of the risk with sufficient time.  

[00:06:54] Paulette: Sure. So what are the biggest known health risks associated with vaping and what areas still require more research?  

[00:07:00] Wendy: Well, let's start with respiratory diseases. You may have heard of the term EVALI. This stands for E-cigarette or Vaping Product Use-Associated Lung Injury. It's a form of pneumonia without infection that's refractory to antibiotics. So EVALI can result in long term lung injury. And in some cases it causes death. Vaping is widely considered to be the cause and the only cause of EVALI, but many cases involved people vaping THC from cannabis. There were a subset of people, however, that were diagnosed with EVALI that have only used nicotine vapes. EVALI is thought to have been caused by vitamin E acetate added to the vape. This is a form of vitamin E that's used in topical treatments. This chemical has previously been found in some vapes, and presumably the industry has made changes to remove it now. 

[00:07:51] Paulette: Right. Okay. So what about COPD? 

[00:07:55] Wendy: Like cancer and cardiovascular disease, COPD takes a long time to develop, so we don't expect to see a huge increase, as most people have been vaping for only ten years or less. But there are some very concerning signs of increased risk. Results from three different cohort studies have indicated a slightly increased risk of COPD for people who vape, compared to those who don't vape or smoke. There are some inconsistencies in the evidence and still a lot of details to work out. So we're not sure that vaping is a cause of COPD yet, but it is very concerning to see this slight increase in risk in three different studies. If vaping does increase the risk of COPD, this could be really disastrous for all the young people vaping at the moment. 

[00:08:42] Paulette: Absolutely. 

[00:08:43] Wendy: I really hope it's not the case. There are also many studies showing a decrease in lung function after vaping, and that's consistent with a possible risk of COPD. 

[00:08:53] Paulette: Okay. And for cardiovascular disease and cancer? 

[00:08:57] Wendy: This is a similar story for cardiovascular diseases and cancer. It's too early to tell from the cohort studies whether people who vape have a higher risk of these, but particularly we're concerned that vaping could increase the risk of cancer. And this is because the emissions from vapes contain quite a few different carcinogens, particularly aldehydes, such as formaldehyde. These chemicals are present at very low levels, usually much lower than tobacco smoke. But carcinogens actually act at low levels because the danger comes from exposure that happens many times a day for years or decades. And there's actually one exception to this low level. The levels of toxic metals can be relatively high in vapes, sometimes even higher than cigarette smoking. And we're particularly concerned about lead and cadmium and arsenic, which are all carcinogens. In people who vape there are some concerning signs of damage that could underlie carcinogenesis. People who vape but don't smoke have higher levels of carcinogens like nitrosamines, cadmium, lead, and other chemicals in their bodies compared to people who don't vape. There are also higher levels of biomarkers of potential harm that are associated with carcinogenesis. These include DNA adducts. So these are signs of chemicals such as acrolein are causing DNA mutations. But we also see oxidative stress, inflammation, and other damage. And particularly we see this damage in the airways such as samples of mouth tissue. 

[00:10:37] Paulette: Right. So tell us about the two studies from South Korea. 

[00:10:41] Wendy: Well these are two very important and recent studies for people who have quit smoking but then vape afterwards. They have a higher risk of lung cancer than people who quit completely. In fact, they actually have the same high risk of lung cancer as people who didn't quit smoking. So you could take this to mean that vaping after quitting smoking has failed to protect these people from lung cancer. However, even though they had the same high risk of lung cancer, there was an improvement in overall survival for these people. So this indicates that it's always beneficial to quit smoking. But I think both of these studies certainly highlight the importance of vaping cessation for people who have quit smoking but vape afterwards. 

[00:11:27] Paulette: Right. Okay. And for cardiovascular diseases? 

[00:11:33] Wendy: For cardiovascular diseases, the evidence is in a similar place to cancer. We can see biomarkers of changes and damage to the cardiovascular system. But there's no solid epidemiology yet. There's no cohort study showing an increased risk of cardiovascular disease. It's likely that it's too soon to see any difference in the relative risks, given that most people who vape are young. So we really don't know the risks of cardiovascular disease yet. 

[00:11:59] Paulette: Right. So are there chemicals in vapes that can lead to cardiovascular disease? 

[00:12:04] Wendy: Well, it's interesting. One difference between tobacco smoke and vaping is that the vape emissions contain almost no carbon monoxide. So carbon monoxide from tobacco smoke, this takes up roughly 10% of the binding spots on hemoglobin in the blood of heavy smokers. And this certainly contributes to the risk of cardiovascular diseases for people who smoke cigarettes. So without this carbon monoxide, we hope that vaping won't be as damaging to the cardiovascular system as smoking. But there are signs of damage in people who vape, such as oxidative stress and impaired microvascular function, and this could put them at risk of cardiovascular diseases in the future. So to summarize, we see some changes and damage in the cardiovascular system and people who vape, but we don't yet know what is the risk of cardiovascular diseases for these people. 

[00:12:59] Paulette: Right. Okay. So in pregnancy, is there evidence of poor outcomes from vaping? 

[00:13:04] Wendy: Yes, there is evidence. There's evidence that there's an increased risk of preterm birth, low birth weight and small for gestational age. And this risk is about 1.5 fold higher than for people who don't vape during pregnancy. 

[00:13:21] Paulette: Right. We actually have an episode on cessation in pregnancy and breastfeeding in the first series of our podcast for those who'd like to listen to that as well. And we'll link to that in our show notes. So tell us about tobacco in Australia and how it can help health professionals. 

[00:13:36] Wendy: I am a writer for a website called Tobacco in Australia Facts and Issues. And honestly, it's a wonderful job, I love it. 

[00:13:44] Paulette: I can imagine. 

[00:13:46] Wendy: Yeah, this is a comprehensive online resource. So it's a bit like Wikipedia. It's an evidence base that covers all tobacco products, as well as vapes and other nicotine products such as pouches. So there's up to date information on things like prevalence of use, the health effects, the factors affecting uptake and cessation, taxation, and economics and the behaviour of the tobacco industry. It's fully referenced and we do not use AI to write up this evidence. 

[00:14:16] Paulette: That's good news. 

[00:14:18] Wendy: It is good news. Tobacco in Australia is written more at an academic level. So this is suitable for clinicians and for researchers and policy makers, but it's less suitable for the general public. I think one of the most interesting sections for clinicians is about cessation interventions in the healthcare system. This is section 7.10 If you wanted to have a read. The website is tobaccoinaustralia.org.au. So this section describes the evidence for smoking cessation interventions that are used in healthcare. And it has separate sections for GPs, pharmacists, dentists and a range of specialties as well as allied health. There is good evidence that interventions delivered by healthcare providers can increase smoking cessation. Even brief, simple advice about quitting increases a patient's chance of cessation. 

[00:15:12] Paulette: Right. 

[00:15:13] Wendy: So if you're interested in using such interventions and you want to know what works, then reading this section would be very helpful for you. 

[00:15:20] Paulette: Thank you so much to our guest doctor Wendy Winnall, for your insights and information on the ever evolving topic of vaping. 

[00:15:28] Wendy: You're very welcome. 

[00:15:29] Paulette: As well as visiting the Tobacco in Australia website, which is an absolute trove of useful information, we invite listeners to also visit the Quit Centre website at quitcentre.org.au for more information and resources for health professionals. And thank you for listening today. Please listen in for future episodes of the Quit Insights Clinical Series podcast. 

This podcast is intended for health professionals and is for educational and informational purposes only. The content discussed does not constitute medical, legal, or professional advice and should not replace your own clinical judgment.