E-cigarettes may damage the heart, scientists have concluded, and have called for Public Health England (PHE) to stop recommending vaping.
Researchers looked at 38 studies into the cardiovascular impact of vaping and found worrying signs of damage in nearly three quarters of tests.
When they discounted trials which had been funded by the tobacco industry - or where the scientists involved had conflicts of interest - the number of studies showing harm rose to 90 per cent.
Asked whether PHE should now change its advice, Martin McKee, Professor of European Public Health at the London School of Hygiene and Tropical Medicine, who co-authored the new analysis said: "The simple answer is yes."
Human studies in the new analysis showed vaping led to an increase in heart rate, blood pressure, arterial stiffness and platelets which cause clotting. It also increased free radicals and reduced anti-oxidants, raising the risk of plaque build-up in the artery walls, which can lead to a heart attack.
Mice exposed to e-cigarette vapour also developed plaques in their arteries and damage to the lining of blood vessels.
Around three million Britons now use e-cigarettes. Since 2015 Public Health England (PHE) has advised smokers to switch to vaping, claiming it is 95 percent safer than smoking tobacco.
However it has since emerged that a study cited by officials to advise that vaping was safe was funded by the e-cigarette industry. Authors of the new analysis also said it was 'concerning' that so many studies funded by the industry had found no harmful cardiovascular effects.
Last week US health officials warned people to quit vaping following the deaths of five people, and at least 215 cases of 'respiratory distress.'
Prof McKee added: "What is amazing is how PHE simply disregards concerns, almost as if people in the UK have lungs that work differently from those in the US.
"Ever since the first appearance of the '95 percent safer' figure we have been concerned about conflict of interest.
"We would be naive not to when dealing with a multi-billion dollar business run largely by the tobacco industry. What is surprising is that some people don't seem to see this as a problem"
An editorial this week in the New England Journal of Medicine, one of the world's leading medical journals, said the US was currently experiencing an 'epidemic of vaping-induced respiratory injury.'
"In light of these cases, efforts should be made to increase public awareness of the harmful effect of vaping, and physicians should discourage their patients from vaping," the journal concluded.
In March the University of Kansas found that vapers are significantly more likely to have a heart attack, develop coronary artery disease and suffer depression compared with those who don't use them. At the time the researchers said it should provide a 'wake up call' to those who thought e-cigarettes were safe.
Earlier this year the head of Britain's biggest addiction clinic warned that children as young as 14 are becoming addicted to e-cigarettes, and said there had been steep rise in the number of young people seeking help to quit vaping.
However despite the deaths and cases of respiratory problems, experts behind the original PHE advice have continued to defend e-cigarettes.
Prof Linda Bauld, Professor of Public Health at the University of Edinburgh, said: "It seems highly unlikely that widely available nicotine containing vaping products, particularly of the type regulated in Europe, are causing these cases.
"Authorities who are reacting to these cases by advising no one to vape are by default sending the message to people who have quit smoking through vaping that they should return to tobacco. This is misleading, and potentially irresponsible.
"Authorities in the USA should be prioritising confirming the causes and addressing this illicit market, not pushing people back to smoking which we know carries multiple risks to health."
Yet US health experts are increasingly concerned.
Vaping researcher Dr Ravi Kalhan, Professor of Medicine at Northwestern University Feinberg School of Medicine said: "Lungs were designed to breathe air, not combinations of various chemicals and oils. The recent news regarding vaping magnifies this once again."
The new study was published in the journal Preventative Medicine.