Using e-cigarettes raises the risk of heart attacks by a third, researchers have warned.
Concerns are growing around the world about the long-term health impact of vaping, amidst booming popularity of the devices.
Yet e-cigarettes remain at the heart of public health policy, with officials repeatedly insisting the benefits far outweigh any potential harms.
The study, to be presented at the American College of Cardiology conference in New Orleans later this month, is one of the largest ever conducted on the impact of vaping.
Scientists found vaping boosts the risk of a heart attack and a stroke by 56 per cent and 30 per cent, respectively
Experts from the University of Kansas examined data from more than 90,000 e-cigarette users.
They found people who vaped every day were 34 per cent more likely than non-e-cigarette users to suffer a heart attack, and those who used the devices more sporadically had a 29 per cent increased risk.
Study leader Dr Mohinder Vindhyal said: ‘Until now, little has been known about cardiovascular events relative to e-cigarette use.
‘These data are a real wake-up call and should prompt more action and awareness about the dangers of e-cigarettes.’
He admitted the study was not perfect – most of the e-cigarette users were ex-smokers so the heart problems could be due to their lifetime of tobacco use.
But he stressed that his team had tried as far as possible to take smoking into account, adding: ‘I wouldn’t want any of my patients nor my family members to vape.’
Roughly a third of the 90,000 e-cigarette users were also smokers.
The team’s initial analysis suggested e-cigarette users had a 56 per cent increased risk of heart attack than those who did not vape.
But taking into account the fact that people who were also regularly smoking tobacco had a 165 per cent increased heart attack risk, they calculated the increased isk of vaping alone dropped to about 34 per cent.
They found e-cigarette users were also 55 per cent more likely to suffer from depression or anxiety.
Dr Vindhyal, however, admitted his team could not completely eradicate the impact of previous tobacco use, because virtually all e-cigarette users in the study had smoked tobacco in the past.
HOW COULD VAPING BE HARMFUL?
The flavourings in electronic cigarettes may damage blood vessels in the same way as heart disease, according to research published in June.
The chemicals used to give the vapour flavours, such as cinnamon, strawberry and banana, can cause inflammation in cells in the arteries, veins and heart.
They causes the body to react in a way that mimics the early signs of heart disease, heart attacks or strokes, the study by Boston University found.
Other recent studies have also suggested smoking e-cigarettes could cause DNA mutations which lead to cancer, and enable pneumonia-causing bacteria to stick to the lungs easier.
Researchers at New York University subjected human bladder and lung cells to e-cigarette vapor, which is marketed as being healthier than tobacco.
They found the cells mutated and became cancerous much faster than expected and mice exposed to the vapour also suffered significant DNA damage.
In another study, scientists at Queen Mary University, London, found vaping makes users more likely to catch pneumonia – just like smoking tobacco or breathing in traffic fumes.
The vapour from e-cigarettes helps bacteria which cause the condition to stick to the cells that line the airways, they said.
The effect occurs with traditional cigarette smoke and those who are exposed to air pollution high in particulates from vehicle exhausts.
Regardless of these caveats, he insisted the findings are concerning and far more research is needed into the risks of e-cigarettes.
‘We found that regardless of how frequently someone uses e-cigarettes, daily or just on some days, they are still more likely to have a heart attack or coronary artery disease,’ he said.
E-cigarettes contain a liquid form of nicotine that is heated into vapour to be inhaled, avoiding the harm caused by tobacco smoke.
Around 3million adults in Britain have used e-cigarettes in the decade or so that they have been on the market.
Public Health England, along with many other health experts in the UK, view e-cigarettes as a crucial tool in the fight against tobacco.
E-cigarettes form the core of Public Health England’s stop-smoking strategy, with TV adverts, health campaigns, and researchers championing the technology.
But other experts – particularly cardiologists – are concerned about unresolved safety concerns and are particularly worried about their use among young people.
Critics have repeatedly warned that the UK is ‘way out of step with the rest of the world’ in its approach to the devices.
The World Health Organisation is concerned about cancer-causing chemicals in the devices and the EU believes e-cigarettes may act as a ‘gateway’ to tobacco.
Last month the then-head of the US Food and Drug Administration (FDA), Scott Gottlieb, said he was so concerned about teenage use of the devices that he is considering the radical step of banning them completely.
An editorial in the respected New England Journal of Medicine research last month warned about the concerns among health professionals in the US.
It warned: ‘While e-cigarettes are ‘safer’ than traditional cigarettes, they are not without risks.
‘Evidence of effectiveness must be balanced against the short-term and long-term safety of e-cigarettes.
‘E-cigarette vapour contains many toxins and exerts potentially adverse biologic effects on human cells… although toxin levels and biologic effects are generally lower than those of tobacco smoke.’
Martin Dockrell, in charge of tobacco policy at Public Health England, said last night: ‘This confirms what PHE has been saying for several years: vaping isn’t risk free but it is far less harmful than smoking. It’s a no brainer – switching to vaping will always be far less harmful than smoking.
‘If you don’t smoke, don’t start and don’t vape. If you do smoke, quit now and consider using an e-cigarette to help you.’
What is an e-cigarette and how is it different to smoking tobacco?
An electronic cigarette (e-cigarette) is a device that allows users to inhale nicotine by heating a vapour from a solution that contain nicotine, propylene and flavourings.
As there is no burning involved, there is no smoke like a traditional cigarette.
But while they have been branded as carrying a lower risk than cigarettes, an increasing swell of studies is showing health dangers.
E-cigarettes do not produce tar or carbon monoxide, but the vapor does contain some harmful chemicals.
Nicotine is the highly addictive chemical which makes it difficult for smokers to quit.
Nearly three million people in Britain use e-cigarettes, and more than nine million Americans.
1. Standard e-cigarette
Battery-powered device containing nicotine e-liquid.
It vaporizes flavored nicotine liquid.
Very similar to normal e-cigarettes but with sleeker design and a higher concentration of nicotine.
Thanks to its ‘nicotine salts’, manufacturers claim one pod delivers the amount of nicotine as a pack of cigarettes.
It is composed of an e-cigarette (battery and temperature control), and a pod of e-liquid which is inserted at the end.
The liquid contains nicotine, chemicals and flavorings.
Like other vaping devices, it vaporizes the e-liquid.
3. IQOS by Philip Morris
Pen-shaped, charged like an iPod.
It is known as a ‘heat not burn’ smokeless device, heating tobacco but not burning it (at 350C compared to 600C as normal cigarettes do).
The company claims this method lowers users’ exposure to carcinogen from burning tobacco.