If asking your mate down the pub about vaping is what they probably say, no one agrees if it's safer or not, so you might as well smoke anyway.
And now what you need is a Cochrane review.
All the facts have been checked at least twice they find there's been a lot that the experts and Brian might give you a different advice.
Hi, I'm Nicola Linson and I'm Jamie Hartman, Boyce.
We're both researchers based at the University of Oxford, where we work with the Cochrane Tobacco Addiction Group.
Welcome to this edition of Let's Talk E-cigarettes. This podcast is a companion to a research project being carried out at the University of Oxford,
where every month we search the e-cigarette research literature to find new studies.
We then use these studies to update our Cochrane systematic review of e-cigarettes for smoking cessation.
This is called a living systematic review. In each episode,
we start by going through the studies we have found that month and then go into more detail about a particular study or topic related to e-cigarettes.
This month, we ran our searches on the first of May and found two new included studies,
three new ongoing studies and two records linked to previously identified studies.
We'll tell you more about the two included studies in a nutshell. The first new paper we found is led by Dr Eliza Skelton,
based at the University of Newcastle in Australia and funded by Hunter Medical Research Institute.
This is actually the right of a study that I discussed in the February edition of our podcast with Professor Billy BNF scheme.
The study recruited people with drug and alcohol use disorders, and in brief,
all participants in the study were provided with the e-cigarettes and were assigned to either quit smoking abruptly or gradually.
Rates of quitting smoking were very similar in both groups, however, as quitting smoking was only measured up to 12 weeks in this study.
And our cut-off is six months will not be including quit data in our review.
We are, however, currently corresponding with the authors regarding their safety data, as discussed with Billy in February.
This was a pilot study that informed a larger, randomised trial,
which is currently in progress called the Harmony trial, so we're really excited to hear the results of that one.
Watch this space! Thanks, Nicola.
Our second trial comes from Associate Professor Sarah Pratt and her team from Dartmouth University in the United States.
Their randomised controlled trial was funded by the National Institute on Drug Abuse and enrolled 240 cigarette smokers with serious mental illness.
The participants were divided equally into intervention and control groups.
The intervention group received disposable and joint nicotine e-cigarettes for eight weeks,
and the control condition didn't receive any further intervention. There were all followed up to six months at six months.
The authors found persistent reductions in the number of cigarettes smoked per day in the e-cigarette group compared to the control condition.
They didn't find any evidence that provided an e-cigarette increased nicotine dependence.
At six months, six participants in the intervention group and two in the control group were not smoking any cigarettes.
Overall, carbon monoxide levels were significantly lower in the e-cigarette group at earlier assessment points, but not at study end.
Now, if you've been listening, you have heard us talk about carbon monoxide before.
It's a poisonous, colourless, odourless gas which is present in varying amounts in indoor and outdoor air.
Cigarette smoke contains really high levels of carbon monoxide, so exhaled carbon monoxide is a common measure in a lot of the studies we look at,
and we're actually going to be talking about it a bit more today in this month's deep dive.
So I had the pleasure of speaking with Professor Neal Benowitz at the US E-cigarettes Summit in Washington, DC earlier this month.
I'll play you the interview I had with him. You'll get a sense of the bustle in the background was a busy event,
and we recorded this during a coffee break after Professor Benowitz just finished giving his talk entitled The Risk Continuum,
in which he reviewed the risks, as well as potential benefits of nicotine delivered from sources other than combustible tobacco.
So to start with, could you just introduce yourself and tell us about your history with e-cigarette research?
So I'm Neil Benowitz. I am an emeritus professor at the University of California, San Francisco.
I practise medicine,
cardiology and clinical pharmacology for many years and got interested in tobacco in general as a major risk factor for cardiovascular disease.
Great. And what I wanted to ask you about a little bit today was one of the things we're interested in talking about
in this podcast is how we understand some of the toxicological data that we got from studies of e-cigarettes.
What we can know from that. What we can't know from that and how that informs our understanding about risk and the continuum of risk.
Obscure science term definition The continuum of risk in this context refers to not all nicotine
products being equally harmful and appreciating that although unlikely to be completely harmless,
some products are not as dangerous as others. So there are basically three sources of data.
One is comparing it to cigarette smoking, so that's important for all the comparisons.
One is what does the e-cigarette aerosol contain in terms of chemicals?
You know, cigarette smoke contains 7000 chemicals, many toxins, and we know that e-cigarette aerosols contain many fewer.
And the ones that are similar are present in much smaller amounts. So that suggests that there's lower risk.
A second thing that we do is we can look at biomarkers of exposure to known toxicants.
So we have a well known profile in cigarette smokers of chemicals that cause oxidative stress.
Obscure science term definition Oxidative stress occurs when there is an excess in oxygen containing molecules called free radicals in the body.
It can lead to an increased risk of negative outcomes,
such as heart disease and some cancers that cause cardiovascular effects that cause inflammation.
And we look at those chemicals that we know are toxicants, and we measure them in the urine or blood of people who switch from cigarettes to vaping.
And by and large, those exposure biomarkers fall to almost the same level as non-smokers.
But for the most part, exposure to the known toxins we can measure is much lower.
That brings me on to something I was going to ask about, which was the unknown unknowns, I suppose,
and obviously makes sense to measure the things that we know are present in people who smoke and cigarette smoke.
Is there a risk in? This might be a really dumb question, but there are things present in e-cigarette vapour contents that aren't there in
cigarette smoke that we're not picking up on because we don't know to measure for them.
Well, there probably are, but the question is how relevant are they?
Yeah. For example, there's some flavours. Yeah, we know that cinnamon flavour is potentially toxic in animal models and potentially in humans as well.
Some e-cigarette products are cinnamon flavoured. Most cigarettes are not.
So I think that that's that's one issue. The thing that's the biggest concern about extrapolation is effects on the lung compared to systemic.
So when you look at toxins in the urine, that's really what your total absorption is.
Yeah, but it doesn't separate out what the effects could be of smaller amounts in your lung over a long period of time.
And the third area of assessment is what is it observed in people who are vaping?
Now there's a problem there because almost all vapers, adult vapers have been cigarette smokers before.
Yeah. And so it's almost impossible when you have something that's a terribly toxic to assess something that may be mildly toxic.
And there are reasons to be concerned that long term vaping say and never smoker could cause some lung problems.
We don't know. We hope not to take 20 years to see it.
In the meantime, if someone can switch, we know that's a benefit. But whether it's safe to vape for 20 or 30 years, we don't know.
And I totally hadn't appreciated the point.
But now it makes obvious sense about measuring things in the urine versus what we'd find if we measured in the lungs.
Is there a good way to look at what's happening in the lungs? Should we be looking at something other than studies of blood, breath and urine?
Well, it's very hard to do in humans. There are some invasive things like, for example,
bronchoscopy where you basically have someone using a cigarette or a cigarette and then
you put a tube down into their lungs and take fluid out and measure what's in the fluid.
Sounds unpleasant and. Doesn't some studies have been done to do that, and so those are informative, but again, those are really short term studies.
Yeah, and it's hard to know what the effects say if you see inflammation.
It's hard to know what a little bit of inflammation is going to do in the long term. Yeah, I mean, it might do something or it might not.
So, you know, my perspective is that we should encourage e-cigarette use to get people off of cigarettes.
My own patients are cardiovascular patients. I do encourage them if they've been quit smoking and they're secure.
Yeah. Harkening back to smoking at to try to quit e-cigarette.
If someone is otherwise healthy and happy doing it, I'm happy going along with them for a period of time.
But we need the data. Yeah, we don't have the data yet, but leads me on to my final question, which is if funding wasn't an option,
if it wasn't a problem, if there are no kind of barriers in the way, what do you think would be the ideal next study in this space?
Well, I don't think we have the population yet to do the study again. All the studies on the adverse effects of vaping, aside from the ones in youth,
we know that youth can have coughing and bronchitis symptoms and worsening of asthma, which are not serious, we think.
But the problem with the long term studies is that if everyone if you've been a smoker for many years, it's hard to sort that out.
We really need longitudinal studies. We also need people who are using vaping without smoking for a long period of time.
Absolutely. And we don't have that now.
So I what would I like to do is take people who started vaping 10 years ago and have been just vaping for that period of time.
Yeah. And see how they're doing. Fantastic. Anything else you want to add?
Well, the only thing that I want to say about e-cigarettes in general is that they're not the same thing.
There are so many different e-cigarette products, and the toxicity is going to vary.
Yeah, the bigger devices with more power. Yeah, higher heat with certain kinds of coils.
It was a much more toxic. And the ones with low power and higher nicotine level because you take in less aerosol.
Yeah. To satisfy your nicotine need. And so I think we have to look at the kind of device as well.
Absolutely. OK, thank you so much. You're welcome, Brian. This is really great to hear that really interesting and balanced view of the
topic and so wonderful that you can speak to Professor Benowitz in person.
So just to give you a bit of background,
we were really interested in covering this topic today because of our funding from the University of Oxford Public Policy Challenge Fund,
which enabled us to do some further analyses in three topics we covered the flavours and long term use topics in March and April's podcasts.
So this month we wanted to talk a bit about the biomarkers that Neal studies in our analysis.
We compared biomarkers of potential harm between people, switching completely to e-cigarettes,
continuing to smoke combustible cigarettes and people who are dual using e-cigarettes and combustible cigarettes.
Based on the studies in our Cochrane review, in which people who smoked were given e-cigarettes to help them quit smoking.
So Jamie, do you want to tell us a bit more about what we found? Absolutely.
So these findings are under peer review, which means they're subject to change.
They're not finalised yet, but in brief, we found that almost all of the biomarkers we looked at that the studies measured
were lower in people exclusively vaping than in those smoking or adult users.
And just a reminder,
these are all studies in which people who smoke are given e-cigarettes at the start of the study for the purpose of helping them quit smoking.
There was no evidence from any of the studies we reviewed that dual users,
so people who smoked at the start were given e-cigarettes but didn't stop smoking and did start using e-cigarettes.
Series in both at the same time were exposing themselves to any more harm than people who continued to smoke without vaping.
And that's an important point,
because I think there's a concern in this area that if you give people who smoke e-cigarettes and they don't stop smoking overall,
they might be exposing themselves to even more harm. But we didn't find any data that suggested that.
So keep an eye out for that paper.
When it's published will let you guys know, but it'll probably be a little while as these things take time, and that's it from us this month.
Thanks so much for listening and to Professor Benowitz for taking the time to talk to us.
Subscribe on iTunes or Spotify and tune in next month for our next episode of Let's Talk E-cigarettes.
Please subscribe on iTunes or Spotify and stay tuned for our next episode.
It is safer this weekend may help your committee in.
Remember to mention the findings we have can tell us what will happen long term, even the.
No, vaping is safer than smoking. We may still find cause because.
Just thinking of switching to. Let's let.
Thank you to Jonathan Livingston Banks for running searches to Elsa Butler for producing this podcast and to all of you for tuning in.
Music is written with Johnny Berliner and I and performed by Johnny. Our living systematic review is supported by funding from Cancer Research UK.
The Cochrane Tobacco Addiction Group also receives core infrastructure funding from the National Institutes for Health Research.
The views expressed in this podcast are those of Nicola and I and do not represent those of the funders.