Switching from tobacco cigarettes to vaping improves blood vessel function within one month, researchers have found, in a study they say supports the use of electronic cigarettes as a tool to quit smoking.

E-cigarettes have becoming a booming business, with the number of people who vape growing rapidly. According to a 2017 report by Ernst and Young, 2.2 million Britons use e-cigarettes, an increase of 55% over three years.

However, there has been much debate over the potential benefits or harm caused by the devices.

The new study suggests switching from tobacco cigarettes to vaping could be a positive move for blood vessels, potentially reducing the risk of heart attacks and strokes.

“Switching from tobacco cigarettes to electronic cigarettes improves your vascular function within the period of a month, significantly,” said Prof Jacob George of the University of Dundee, first author of the study.

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The study pushes back against research published earlier this week that suggested e-cigarette use might impair blood vessel function. George and colleagues say that study was very small and flawed – not least because it looked only at the impact of a single vaping session.

Writing in the Journal of the American College of Cardiology, George and colleagues report that they looked at data from 114 adults, split into three groups, all of whom smoked at least 15 cigarettes a day for at least two years but had no signs of cardiovascular disease.

One group contained 40 people who did not wish to quit traditional smoking, while the other two groups each contained 37 similar people who did, with one group given devices containing nicotine and the other given e-cigarettes without nicotine.

The team measured blood vessel function at the outset of the study, and after one month, by comparing artery diameter before a tight cuff was applied to an arm with artery diameter just after the cuff was released. This percentage change is larger in healthier vessels.

They found those who continued to smoke tobacco cigarettes showed little difference in their blood vessel function over the month.. However, those in the vaping groups had more than a 20% relative improvement in the measure and were halfway back to having blood vessel function on a par with non-smokers. Similar results were found for those switching to e-cigarettes with and without nicotine.

Quick guide Is vaping dangerous? Show Hide Is it true that e-cigarettes have caused deaths in the United States? There have been six confirmed deaths connected to vaping across the US – in California, Illinois, Indiana, Kansas, Minnesota and Oregon – as well as more than 450 cases of reported lung problems. What have the authorities found out so far? The federal government’s CDC (Centers for Disease Control) says no specific substance or single type of device has been linked to all cases. But in most cases – about 80% – people have said they were using liquids that contained cannabinoid products, such as tetrahydrocannabinol (THC). Most of those are said by the Food and Drug Administration (FDA), which is investigating with the CDC, to also contain a substance called vitamin E acetate. It appears some people may have bought their e-cigarettes or other devices off the street. What is the advice in the US? The CDC is suggesting anyone who vapes should consider stopping during its investigation. Young people and pregnant women should not use e-cigarettes at all, it says. It advises people who are using e-cigarettes to try to stop smoking to consider other methods, such as counselling or medication. Is vaping dangerous? It depends who you talk to. Public Health England and most, but not all, of the public health community in the UK say it is not dangerous. PHE is on record as saying it is 95% safer than smoking – which kills half of all of those who take up the habit. UK scientists and campaigners are focused on e-cigarettes as a way for adults to quit smoking. In the US, however, there is far more interest in the chemicals contained in e-cigarettes and the possibility of any toxicity. Experts are not convinced that e-cigarettes can help people stop smoking and talk of potential harms and unknown risks rather than possible benefits. The absence of regulation in the US means there is no cap on nicotine levels in e-cigarette liquids, making stronger doses more addictive. The UK has a strict limit, thanks to an EU directive now enshrined in British law. Sarah Boseley Health editor

Further analysis, taking into account factors such as sex, age and how heavily participants had previously smoked, showed that on average, participants who switched to vaping had a 1.5 percentage point improvement in their change in artery diameter, compared with the group that kept smoking.

The team say if such an improvement was sustained over the long term, it could bring important health benefits: previous research has suggested a one percentage point improvement in blood vessel function is linked to a 13% lower risk of cardiovascular events.

George noted that women seemed to improve more when switching to vaping than men, although it is not clear why. The benefits were greater the better participants stuck to the switch.

However, the team stress that while the study suggests vaping might be less harmful than tobacco cigarettes, it does not prove the devices are safe.

“This study doesn’t show that vaping is safe; it shows that there are effects on the vascular system within a month, which mean that your vascular health improves if you are a smoker and switch to vaping” said Prof Jeremy Pearson from the British Heart Foundation, which funded the study.

“We would not advocate anybody taking up vaping if they don’t smoke,” he said, noting that the claim from Public Health England that vaping is 95% less harmful than smoking was based on a “simplistic” calculation.

Tim Chico, a professor of cardiovascular medicine at the University of Sheffield, who was not involved in the study, said the research suggested vaping was less damaging than smoking when it came to blood vessels.

But, he added, the results are preliminary and long-term studies were needed to investigate the impact of vaping on heart attack, stroke or cancer risk.

“In addition, this study did not measure other possible ways that cigarettes and e-cigarettes can increase risk of heart disease, such as the tendency to form blood clots, which is an important part of why tobacco smokers are more likely to suffer heart attacks,” he said.

“While vaping isn’t risk-free, it’s much less risky than smoking, which kills over 250 people a day in the UK,” said Deborah Arnott, the chief executive of the charity Action on Smoking and Health. “Vapers shouldn’t be scared back to smoking – that really would cost lives.”