Vaping without nicotine still harms blood vessels, Penn study finds

A growing body of research suggests that electronic cigarettes can damage blood vessels in the short term, causing them to become inflamed and stiff, even when the vaping liquid does not contain nicotine. What’s not yet clear is which of the various inhaled components of e-liquids are to blame.

In a new University of Pennsylvania study, researchers found the kind of damage associated with developing atherosclerosis — popularly called hardening of the arteries.

Blood flow and other markers of vascular function returned to normal an hour after the study participants used a vaping device without nicotine, so it is unknown if long-term use would cause permanent damage, said senior author Felix W. Wehrli.

But if so, he said, the findings are reason for concern.

“All of these are measures that are suggestive of a disturbance of the vascular system,” Wehrli said. “You can imagine for somebody who keeps on vaping at regular intervals, daily, for weeks, month, and years, that the parameters would never go down to baseline.”

Most studies of e-cigarettes have examined the effects of vaping liquids that contain nicotine. An addictive substance, it represents the main attraction for vapers, some of whom use the devices in an attempt to quit cigarettes. But increasingly, some users opt for nicotine-free vaping liquids in an attempt to wean themselves.

Yet just as e-cigarettes with nicotine are not a harmless alternative to cigarettes, e-cigarettes without nicotine seem to pose risks, said Wehrli, a professor of radiologic science and biophysics at Penn’s Perelman School of Medicine. Some nonsmokers, including youths, also have tried nicotine-free vaping — a bad idea, he said.

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The study, published in the journal Radiology, consisted of 31 participants who had never smoked or vaped, with an average age of 24.

Each took 16 puffs from a vaping device, lasting three seconds at a time.

Researchers measured the participants’ blood-vessel function before and after the vaping. They restricted blood flow by placing a cuff on each person’s right thigh for five minutes, then used MRIs to gauge how well their blood vessels recovered.

After vaping, the scans revealed a 34 percent reduction in how much the participants’ femoral arteries dilated when the cuff was removed, on average, when compared to the same measurement before vaping. The researchers also measured a 17.5 percent reduction in peak blood-flow velocity after vaping and a 20 percent drop in the oxygen levels of participants’ leg veins.

Some of the damage may be due to the specific chemistry of the substances involved, whereas some harm may be due to the fact that the particles, regardless of type, are so small, said lead study author Alessandra Caporale, a post-doctoral researcher.

“They can go deep into your lungs,” she said.

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Neal L. Benowitz, who has studied e-cigarettes at the University of California, San Francisco, praised the Penn researchers for their use of high-tech methods to measure blood-vessel function.

He cautioned that their study involved just one type of vaping device — the Eco series made by ePuffer — and that the findings should not be generalized to reflect all e-cigarettes. Devices that operate at higher temperatures may be riskier, for example.

“The hotter it is, the more thermal degradation products you generate,” said Benowitz, a professor of medicine. Lower-temperature devices, likewise, would presumably be safer, he said. And none contains the tar that is found in cigarettes.