1 00:00:06,370 --> 00:00:18,700 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. 2 00:00:18,700 --> 00:00:22,780 And now what you need is a Cochrane review. 3 00:00:22,780 --> 00:00:36,110 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. 4 00:00:36,110 --> 00:00:39,290 Hi, I'm Nicola Linson and I'm Jamie Hartman, Boyce. 5 00:00:39,290 --> 00:00:44,600 We're both researchers based at the University of Oxford, where we work with the Cochrane Tobacco Addiction Group. 6 00:00:44,600 --> 00:00:52,520 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, 7 00:00:52,520 --> 00:00:57,110 where every month we search the e-cigarette research literature to find new studies. 8 00:00:57,110 --> 00:01:02,900 We then use these studies to update our Cochrane systematic review of e-cigarettes for smoking cessation. 9 00:01:02,900 --> 00:01:06,770 This is called a living systematic review. In each episode, 10 00:01:06,770 --> 00:01:14,480 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. 11 00:01:14,480 --> 00:01:18,560 This month, we ran our searches on the first of May and found two new included studies, 12 00:01:18,560 --> 00:01:23,030 three new ongoing studies and two records linked to previously identified studies. 13 00:01:23,030 --> 00:01:31,670 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, 14 00:01:31,670 --> 00:01:37,430 based at the University of Newcastle in Australia and funded by Hunter Medical Research Institute. 15 00:01:37,430 --> 00:01:44,330 This is actually the right of a study that I discussed in the February edition of our podcast with Professor Billy BNF scheme. 16 00:01:44,330 --> 00:01:48,080 The study recruited people with drug and alcohol use disorders, and in brief, 17 00:01:48,080 --> 00:01:54,470 all participants in the study were provided with the e-cigarettes and were assigned to either quit smoking abruptly or gradually. 18 00:01:54,470 --> 00:02:01,190 Rates of quitting smoking were very similar in both groups, however, as quitting smoking was only measured up to 12 weeks in this study. 19 00:02:01,190 --> 00:02:05,840 And our cut-off is six months will not be including quit data in our review. 20 00:02:05,840 --> 00:02:12,710 We are, however, currently corresponding with the authors regarding their safety data, as discussed with Billy in February. 21 00:02:12,710 --> 00:02:16,190 This was a pilot study that informed a larger, randomised trial, 22 00:02:16,190 --> 00:02:22,100 which is currently in progress called the Harmony trial, so we're really excited to hear the results of that one. 23 00:02:22,100 --> 00:02:25,550 Watch this space! Thanks, Nicola. 24 00:02:25,550 --> 00:02:32,390 Our second trial comes from Associate Professor Sarah Pratt and her team from Dartmouth University in the United States. 25 00:02:32,390 --> 00:02:40,160 Their randomised controlled trial was funded by the National Institute on Drug Abuse and enrolled 240 cigarette smokers with serious mental illness. 26 00:02:40,160 --> 00:02:44,090 The participants were divided equally into intervention and control groups. 27 00:02:44,090 --> 00:02:48,470 The intervention group received disposable and joint nicotine e-cigarettes for eight weeks, 28 00:02:48,470 --> 00:02:55,640 and the control condition didn't receive any further intervention. There were all followed up to six months at six months. 29 00:02:55,640 --> 00:03:02,960 The authors found persistent reductions in the number of cigarettes smoked per day in the e-cigarette group compared to the control condition. 30 00:03:02,960 --> 00:03:07,910 They didn't find any evidence that provided an e-cigarette increased nicotine dependence. 31 00:03:07,910 --> 00:03:14,180 At six months, six participants in the intervention group and two in the control group were not smoking any cigarettes. 32 00:03:14,180 --> 00:03:22,040 Overall, carbon monoxide levels were significantly lower in the e-cigarette group at earlier assessment points, but not at study end. 33 00:03:22,040 --> 00:03:25,490 Now, if you've been listening, you have heard us talk about carbon monoxide before. 34 00:03:25,490 --> 00:03:31,640 It's a poisonous, colourless, odourless gas which is present in varying amounts in indoor and outdoor air. 35 00:03:31,640 --> 00:03:39,590 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, 36 00:03:39,590 --> 00:03:47,430 and we're actually going to be talking about it a bit more today in this month's deep dive. 37 00:03:47,430 --> 00:03:54,270 So I had the pleasure of speaking with Professor Neal Benowitz at the US E-cigarettes Summit in Washington, DC earlier this month. 38 00:03:54,270 --> 00:03:58,410 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, 39 00:03:58,410 --> 00:04:05,970 and we recorded this during a coffee break after Professor Benowitz just finished giving his talk entitled The Risk Continuum, 40 00:04:05,970 --> 00:04:13,050 in which he reviewed the risks, as well as potential benefits of nicotine delivered from sources other than combustible tobacco. 41 00:04:13,050 --> 00:04:18,180 So to start with, could you just introduce yourself and tell us about your history with e-cigarette research? 42 00:04:18,180 --> 00:04:24,870 So I'm Neil Benowitz. I am an emeritus professor at the University of California, San Francisco. 43 00:04:24,870 --> 00:04:26,940 I practise medicine, 44 00:04:26,940 --> 00:04:35,490 cardiology and clinical pharmacology for many years and got interested in tobacco in general as a major risk factor for cardiovascular disease. 45 00:04:35,490 --> 00:04:41,430 Great. And what I wanted to ask you about a little bit today was one of the things we're interested in talking about 46 00:04:41,430 --> 00:04:49,620 in this podcast is how we understand some of the toxicological data that we got from studies of e-cigarettes. 47 00:04:49,620 --> 00:04:58,830 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. 48 00:04:58,830 --> 00:05:05,580 Obscure science term definition The continuum of risk in this context refers to not all nicotine 49 00:05:05,580 --> 00:05:10,980 products being equally harmful and appreciating that although unlikely to be completely harmless, 50 00:05:10,980 --> 00:05:17,700 some products are not as dangerous as others. So there are basically three sources of data. 51 00:05:17,700 --> 00:05:22,650 One is comparing it to cigarette smoking, so that's important for all the comparisons. 52 00:05:22,650 --> 00:05:28,170 One is what does the e-cigarette aerosol contain in terms of chemicals? 53 00:05:28,170 --> 00:05:37,080 You know, cigarette smoke contains 7000 chemicals, many toxins, and we know that e-cigarette aerosols contain many fewer. 54 00:05:37,080 --> 00:05:43,710 And the ones that are similar are present in much smaller amounts. So that suggests that there's lower risk. 55 00:05:43,710 --> 00:05:49,020 A second thing that we do is we can look at biomarkers of exposure to known toxicants. 56 00:05:49,020 --> 00:05:56,220 So we have a well known profile in cigarette smokers of chemicals that cause oxidative stress. 57 00:05:56,220 --> 00:06:06,150 Obscure science term definition Oxidative stress occurs when there is an excess in oxygen containing molecules called free radicals in the body. 58 00:06:06,150 --> 00:06:08,610 It can lead to an increased risk of negative outcomes, 59 00:06:08,610 --> 00:06:15,300 such as heart disease and some cancers that cause cardiovascular effects that cause inflammation. 60 00:06:15,300 --> 00:06:23,130 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. 61 00:06:23,130 --> 00:06:29,340 And by and large, those exposure biomarkers fall to almost the same level as non-smokers. 62 00:06:29,340 --> 00:06:34,380 But for the most part, exposure to the known toxins we can measure is much lower. 63 00:06:34,380 --> 00:06:40,530 That brings me on to something I was going to ask about, which was the unknown unknowns, I suppose, 64 00:06:40,530 --> 00:06:47,550 and obviously makes sense to measure the things that we know are present in people who smoke and cigarette smoke. 65 00:06:47,550 --> 00:06:57,420 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 66 00:06:57,420 --> 00:07:01,740 cigarette smoke that we're not picking up on because we don't know to measure for them. 67 00:07:01,740 --> 00:07:06,270 Well, there probably are, but the question is how relevant are they? 68 00:07:06,270 --> 00:07:15,870 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. 69 00:07:15,870 --> 00:07:20,340 Some e-cigarette products are cinnamon flavoured. Most cigarettes are not. 70 00:07:20,340 --> 00:07:29,140 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. 71 00:07:29,140 --> 00:07:33,090 So when you look at toxins in the urine, that's really what your total absorption is. 72 00:07:33,090 --> 00:07:39,210 Yeah, but it doesn't separate out what the effects could be of smaller amounts in your lung over a long period of time. 73 00:07:39,210 --> 00:07:45,690 And the third area of assessment is what is it observed in people who are vaping? 74 00:07:45,690 --> 00:07:51,300 Now there's a problem there because almost all vapers, adult vapers have been cigarette smokers before. 75 00:07:51,300 --> 00:07:57,300 Yeah. And so it's almost impossible when you have something that's a terribly toxic to assess something that may be mildly toxic. 76 00:07:57,300 --> 00:08:04,110 And there are reasons to be concerned that long term vaping say and never smoker could cause some lung problems. 77 00:08:04,110 --> 00:08:07,830 We don't know. We hope not to take 20 years to see it. 78 00:08:07,830 --> 00:08:14,010 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. 79 00:08:14,010 --> 00:08:16,740 And I totally hadn't appreciated the point. 80 00:08:16,740 --> 00:08:22,770 But now it makes obvious sense about measuring things in the urine versus what we'd find if we measured in the lungs. 81 00:08:22,770 --> 00:08:29,820 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? 82 00:08:29,820 --> 00:08:34,590 Well, it's very hard to do in humans. There are some invasive things like, for example, 83 00:08:34,590 --> 00:08:39,600 bronchoscopy where you basically have someone using a cigarette or a cigarette and then 84 00:08:39,600 --> 00:08:43,920 you put a tube down into their lungs and take fluid out and measure what's in the fluid. 85 00:08:43,920 --> 00:08:52,890 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. 86 00:08:52,890 --> 00:08:57,170 Yeah, and it's hard to know what the effects say if you see inflammation. 87 00:08:57,170 --> 00:09:02,720 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. 88 00:09:02,720 --> 00:09:08,780 So, you know, my perspective is that we should encourage e-cigarette use to get people off of cigarettes. 89 00:09:08,780 --> 00:09:14,930 My own patients are cardiovascular patients. I do encourage them if they've been quit smoking and they're secure. 90 00:09:14,930 --> 00:09:17,690 Yeah. Harkening back to smoking at to try to quit e-cigarette. 91 00:09:17,690 --> 00:09:22,520 If someone is otherwise healthy and happy doing it, I'm happy going along with them for a period of time. 92 00:09:22,520 --> 00:09:30,410 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, 93 00:09:30,410 --> 00:09:37,310 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? 94 00:09:37,310 --> 00:09:45,200 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, 95 00:09:45,200 --> 00:09:55,190 we know that youth can have coughing and bronchitis symptoms and worsening of asthma, which are not serious, we think. 96 00:09:55,190 --> 00:10:01,160 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. 97 00:10:01,160 --> 00:10:07,100 We really need longitudinal studies. We also need people who are using vaping without smoking for a long period of time. 98 00:10:07,100 --> 00:10:09,680 Absolutely. And we don't have that now. 99 00:10:09,680 --> 00:10:16,010 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. 100 00:10:16,010 --> 00:10:19,850 Yeah. And see how they're doing. Fantastic. Anything else you want to add? 101 00:10:19,850 --> 00:10:26,390 Well, the only thing that I want to say about e-cigarettes in general is that they're not the same thing. 102 00:10:26,390 --> 00:10:30,500 There are so many different e-cigarette products, and the toxicity is going to vary. 103 00:10:30,500 --> 00:10:37,190 Yeah, the bigger devices with more power. Yeah, higher heat with certain kinds of coils. 104 00:10:37,190 --> 00:10:43,140 It was a much more toxic. And the ones with low power and higher nicotine level because you take in less aerosol. 105 00:10:43,140 --> 00:10:47,360 Yeah. To satisfy your nicotine need. And so I think we have to look at the kind of device as well. 106 00:10:47,360 --> 00:10:54,860 Absolutely. OK, thank you so much. You're welcome, Brian. This is really great to hear that really interesting and balanced view of the 107 00:10:54,860 --> 00:11:00,110 topic and so wonderful that you can speak to Professor Benowitz in person. 108 00:11:00,110 --> 00:11:02,030 So just to give you a bit of background, 109 00:11:02,030 --> 00:11:09,380 we were really interested in covering this topic today because of our funding from the University of Oxford Public Policy Challenge Fund, 110 00:11:09,380 --> 00:11:18,530 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. 111 00:11:18,530 --> 00:11:24,650 So this month we wanted to talk a bit about the biomarkers that Neal studies in our analysis. 112 00:11:24,650 --> 00:11:29,810 We compared biomarkers of potential harm between people, switching completely to e-cigarettes, 113 00:11:29,810 --> 00:11:36,830 continuing to smoke combustible cigarettes and people who are dual using e-cigarettes and combustible cigarettes. 114 00:11:36,830 --> 00:11:42,890 Based on the studies in our Cochrane review, in which people who smoked were given e-cigarettes to help them quit smoking. 115 00:11:42,890 --> 00:11:47,250 So Jamie, do you want to tell us a bit more about what we found? Absolutely. 116 00:11:47,250 --> 00:11:50,810 So these findings are under peer review, which means they're subject to change. 117 00:11:50,810 --> 00:11:57,620 They're not finalised yet, but in brief, we found that almost all of the biomarkers we looked at that the studies measured 118 00:11:57,620 --> 00:12:02,300 were lower in people exclusively vaping than in those smoking or adult users. 119 00:12:02,300 --> 00:12:03,020 And just a reminder, 120 00:12:03,020 --> 00:12:09,740 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. 121 00:12:09,740 --> 00:12:13,730 There was no evidence from any of the studies we reviewed that dual users, 122 00:12:13,730 --> 00:12:19,800 so people who smoked at the start were given e-cigarettes but didn't stop smoking and did start using e-cigarettes. 123 00:12:19,800 --> 00:12:25,760 Series in both at the same time were exposing themselves to any more harm than people who continued to smoke without vaping. 124 00:12:25,760 --> 00:12:26,750 And that's an important point, 125 00:12:26,750 --> 00:12:33,470 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, 126 00:12:33,470 --> 00:12:38,390 they might be exposing themselves to even more harm. But we didn't find any data that suggested that. 127 00:12:38,390 --> 00:12:40,790 So keep an eye out for that paper. 128 00:12:40,790 --> 00:12:47,510 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. 129 00:12:47,510 --> 00:12:51,740 Thanks so much for listening and to Professor Benowitz for taking the time to talk to us. 130 00:12:51,740 --> 00:12:58,170 Subscribe on iTunes or Spotify and tune in next month for our next episode of Let's Talk E-cigarettes. 131 00:12:58,170 --> 00:13:02,280 Please subscribe on iTunes or Spotify and stay tuned for our next episode. 132 00:13:02,280 --> 00:13:07,640 It is safer this weekend may help your committee in. 133 00:13:07,640 --> 00:13:14,940 Remember to mention the findings we have can tell us what will happen long term, even the. 134 00:13:14,940 --> 00:13:20,770 No, vaping is safer than smoking. We may still find cause because. 135 00:13:20,770 --> 00:13:36,390 Just thinking of switching to. Let's let. 136 00:13:36,390 --> 00:13:42,600 Thank you to Jonathan Livingston Banks for running searches to Elsa Butler for producing this podcast and to all of you for tuning in. 137 00:13:42,600 --> 00:13:50,640 Music is written with Johnny Berliner and I and performed by Johnny. Our living systematic review is supported by funding from Cancer Research UK. 138 00:13:50,640 --> 00:13:56,490 The Cochrane Tobacco Addiction Group also receives core infrastructure funding from the National Institutes for Health Research. 139 00:13:56,490 --> 00:14:01,448 The views expressed in this podcast are those of Nicola and I and do not represent those of the funders.