Smokers are increasingly unconvinced of the benefits of switching to e-cigarettes, or ‘vaping’ – using an electronic device to heat a liquid that contains nicotine and inhaling the vapour (as opposed to breathing in the smoke from burning tobacco).
Last year, over a third of smokers surveyed in England thought vaping would be more harmful to their health than smoking – up from 12 per cent four years earlier – while another third thought vaping would be just as bad.
This is despite scientific evidence from the National Institute for Health and Care Excellence (NICE) showing the effects of smoking on our health, and a Cochrane review from 2022 that suggests vaping helps more people to quit than other nicotine replacement products.
So, the perception of vaping is important because, as scientists established this year, smokers who think vaping is less harmful are more likely to switch.
While there are known health impacts of both vaping and smoking, many experts agree that vaping reduces harm compared to smoking. According to the National Health Service, for example, vaping exposes people to fewer toxins, and at lower levels, than smoking.
“It’s not that we think e-cigarettes are totally safe, but smoking is uniquely deadly and kills one in two regular users,” says Dr Jamie Hartmann-Boyce, whose work in health policy at the University of Massachusetts Amherst, in the US, focuses on tobacco control and e-cigarettes.
“So, when we’re comparing most things to smoking, most things come out looking better.”
From the public’s perspective, however, the picture is complicated by media reports sensationalising the harms of vaping while failing to emphasise everything we already know is harmful about smoking.
Why? Probably because the health risks associated with smoking are old news and tend to affect older people, suggests Dr Sarah Jackson, a principal research fellow in University College London’s Alcohol and Tobacco Research Group.
“I think if smoking was killing lots of young people, it would be all over the news,” she says, “Obviously, it’s not good news that there are young people vaping, but I do think that attracts the attention.”
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Health risks
While it might be old news, it bears repeating that smoking is a risk factor for cancer, heart disease, infertility and problems in pregnancy, as well as a host of other health issues, and kills over eight million people every year.
Scientists may not have done as much research on vaping, but burning tobacco in cigarette form produces a greater mix of toxic substances compared to heating the nicotine-containing liquid in a vape.
According to Jackson, then, we should be “quite confident” that vaping is less harmful than smoking and while she admits that more long-term studies are due, we shouldn’t be under any illusions about the results.
“There may be long-term risks that we don’t know about and people think that means they could potentially be as bad as [the risks] for smoking. But all the evidence we have points towards that being incredibly unlikely.”
It’s the longer-term effects that Dr Maxime Boidin, a senior lecturer in cardiac rehabilitation at Manchester Metropolitan University has been researching.
Although, as a cardiac specialist, his study looks specifically at damage to blood vessels relevant to heart disease risk – not the overall health effects.
As Boidin explains, some studies already suggest that vaping reduces the influence of signalling molecules (nitric oxide) needed to keep blood vessels relaxed and healthy, as does smoking.
“What we don’t know is, if that mechanism happens, what happens to the blood vessel?” he says. “I’m trying to answer this question.”
Boidin’s study, which was due to be finished at the end of March, uses a clinically validated measure of how much blood vessels can expand to assess damage in people who have vaped for three to five years, compared to people who have smoked traditional tobacco products for a similar period.
Once completed, the study will go through the normal process of peer review before being published in a scientific journal.
Results being reported in the media before this process is complete (as was the case with Boidin’s study) can be a source of frustration for experts who are unable to judge the quality of the research or comment on the end results without a published paper.
Even when the study is published, it’ll only tell us about the effects of vaping on the cardiovascular system, not, notes Boidin, any of the other aspects addressed in some press articles. “I’m not talking about the brain or the lungs,” he says.
Media articles reporting on Boidin’s study did, though, lead to discussions about how scientists can carry out fair trials comparing vaping with smoking. An ideal study would be one where healthy people who have never smoked or vaped before were assigned to smoking or vaping groups and then monitored over a number of years.
This type of trial is, obviously, an ethical impossibility considering the harms, so scientists have instead looked at what changes when smokers switch to vaping.
“The evidence is really clear there. Those who do, reduce their health risks and that tells us that vaping, for those people, is likely to be substantially less harmful than smoking,” says Hartmann-Boyce.
Another option is to do a study more like Boidin’s, where scientists take measurements from people who have already chosen to vape or smoke.
The difficulty here is ensuring that the vaping and smoking groups match in every respect so that factors like fitness, age or income level don’t influence the results. What’s more, vapers tend to be previous smokers so it can be hard to rule out historic damage caused by smoking.
Non-smokers turned vapers
Hartmann-Boyce is the lead author of the previously mentioned Cochrane review, which is regularly updated with new evidence from trials of e-cigarettes for helping people quit smoking. The review shows that, in trials, e-cigarettes are more helpful than other nicotine replacements such as patches or gums.
Jackson’s recent work, meanwhile, backs up this finding with evidence from the real world, while showing that vaping is also now the most common method people use to quit smoking – used in about 40 per cent of attempts to quit in England.
When we consider people who have never smoked, however, vaping does pose more of a concern. The number of people who vape without having smoked previously has grown rapidly since 2020 – increasing seven-fold in England to exceed a million by April 2024. And as all our experts agreed, the health effects associated with vaping can’t be zero.
“You’re inhaling a host of chemicals that aren’t clean air into your lungs,” says Hartmann-Boyce, noting that we also need to consider the impacts of nicotine addiction. Whether vaping is more addictive has also been widely debated.
So, should the public message be: if you have to choose, choose vaping?
“Exactly that,” Jackson agrees. “If the choice is between vaping and fresh air, choose fresh air. But if the choice is between vaping and smoking then yes, every day of the week, choose vaping.”
About our experts
Dr Jamie Hartmann-Boyce is an Assistant Professor of Health Policy and Management based at the University of Massachusetts, Amherst. Her work has been published in the British Medical Journal, the Cochrane Database of Systematic Reviews and the JAMA Network.
Dr Sarah Jackson is a Principal Research Fellow in the UCL Alcohol and Tobacco Research Group. Her work has been published in the journals Addiction, The Lancet Public Health and the British Medical Journal.
Dr Maxime Boidin is a Senior Lecturer in Cardiac Rehabilitation based at Manchester Metropolitan University. His research has been published in the Journal of Applied Physiology, Physiological Reports and the Journal of Cardiovascular Medicine.
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