London - Vaping may damage blood vessels in a similar way to smoking, potentially raising the risk of suffering a heart attack or stroke.
A study has found concerning signs of stiffened arteries in young people who use e-cigarettes.
The cells lining their blood vessels also appeared less able to protect their heart. The chemicals which give e-cigarettes their flavour may be partly to blame, although more analysis is needed.
Researchers in the US recruited 285 smokers and 36 vapers, who they compared to non-smokers and ‘dual users’ of both cigarettes and e-cigarettes. The participants should have had healthy blood vessels, expanding and recoiling as their hearts pumped blood around their body.
But ultrasound images of blood flow and pressure showed smokers had stiffer arteries, and the stiffness was similar in those who vaped. A similar stiffness was also seen in people who both smoked and vaped.
While those who vaped had all smoked before, previous studies have also suggested vaping is bad for blood vessels and could raise the risk of heart problems.
Lead author Dr Jessica Fetterman, of Boston University, said: "The evidence from scientific studies is growing that e-cigarettes might not be the safer alternative when it comes to heart health. Our study adds to that evidence."
Subjects smoked, vaped or did both at least five days a week. Those who vaped had quit smoking at least three months previously and were more likely to be young and male.
Researchers put a wire into a vein in the arms of those who vaped to remove cells which lined their blood vessels. When these cells were chemically triggered to make a heart-protective chemical in the lab, they produced less of it.
The artery stiffness is unlikely to be an immediate problem in young people.But the researchers, whose study is published in the Journal of the American Heart Association, conclude it could raise their risk of artery stiffness in the aorta – the major artery leading from the heart – which could then lead to heart problems.