A study of young people has found just 16 puffs of a nicotine-free e-cigarette can cause a major drop in blood flow to the main artery of the leg, something the authors say mimics the effects of aging.
Electronic cigarettes use a hot metal element to turn an e-liquid, with or without nicotine, into an aerosol that is inhaled. It’s called vaping, and is seen by some as safer than traditional smoking because no tobacco is burned.
It is also getting popular with teens. The US Centres for Disease Control and Prevention report 1.5 million more high school students vaping in 2018 compared to the previous year, a 71% surge.
The study’s authors, led by Felix Wehrli from the University of Pennsylvania, US, were spurred by data suggesting non-nicotine elements in the vaping aerosol are more toxic than people might think.
E-liquids contain propylene glycol and glycerol which, at room temperature, form lung-irritants called acetals. The aerosol also has ultrafine metal particles from the heating element that cause oxidative stress a whole-body inflammation linked to a plethora of illnesses including cancer.
Standard tobacco smoking damages blood vessels – the flexible tubes carrying blood around the body – causing stroke, heart attacks and sometimes amputated limbs.
Wehrli’s team wanted to see how those blood vessels fared in the face of a vaping challenge. They enlisted 31 non-smokers, with an average age of 24, to have MRI scans measure the blood flow in their leg and aorta – the big artery coming out of the heart – before and after puffing on a nicotine-free, tobacco-flavoured e-cigarette.
The measurements were done after releasing a tourniquet from the leg which caused a surge of blood into the oxygen-starved limb, a phenomenon called “reactive hyperaemia”.
The results may well prompt a re-think for people who think e-cigarettes are a safe option.
Blood velocity in the leg’s major artery dropped by a largish 17% after vaping. Dilation of the same vessel was down 34% after the e-cig. On top of all that, the speed at which blood flow returned to normal after release of the cuff fell by 26% post-puff.
“The alterations in reactive hyperaemic response parallel those observed in older people because of physiologic aging,” the authors write. Even the aorta – which became marginally stiffer – was affected.