MONDAY, Sept. 11, 2017 -- Nicotine in e-cigarettes may cause stiffened arteries, which can lead to an increased risk for heart attack and stroke, a small Swedish study suggests.
With the dramatic increase in e-cigarette use ("vaping") over the past few years, questions have arisen about their safety. And while many people think the devices are harmless, especially compared with regular cigarettes, little is known about long-term effects of these devices, according to lead researcher Magnus Lundback, from the Karolinska Institute in Stockholm.
"Increased arterial stiffness has previously been demonstrated following exposure to conventional cigarettes," said Lundback, who is a research leader and clinical registrar at the Danderyd University Hospital.
"We think that chronic exposure to e-cigarettes with nicotine may lead to stiffer arteries and, in the long run, an increased risk of cardiovascular disease," he said. "However, these results demonstrated the acute effects. Long-term studies on chronic e-cigarette exposure need to be performed to be certain."
These findings highlight the need to be cautious about using e-cigarettes, Lundback said. People should be aware of the potential dangers so they can decide whether to use them based on scientific evidence, he said.
Dr. Norman Edelman, a senior scientific advisor to the American Lung Association, said it's important to focus on the effects of e-cigarettes on the cardiovascular system.
"If you look at what kills cigarette smokers, more die from cardiovascular disease than lung disease," he said.
"We really can't tell patients that e-cigarettes are really a safe alternative to real cigarettes -- there is evidence of some harm," Edelman added.
It's especially important that e-cigarettes not be available to teenagers, "because once they get hooked on nicotine, they are likely to use nicotine products for a long time," he explained.
Although e-cigarettes have been touted as a way to help smokers quit, Edelman doesn't believe they're a safe alternative to other methods.
"The American Lung Association has not endorsed the use of e-cigarettes for smoking cessation," he said.
"We take the position that there are several products available that are FDA [U.S. Food and Drug Administration] tested and approved for smoking cessation. There is no reason for us to endorse a product that hasn't been tested and approved for that purpose by the FDA," Edelman said.
In 2016, Lundback and his colleagues recruited 15 young, healthy adults. These volunteers smoked only about 10 cigarettes a month and had never tried e-cigarettes.
The researchers randomly assigned the participants to use e-cigarettes that included nicotine for 30 minutes on one day and e-cigarettes without nicotine on another.
Lundback's team measured blood pressure, heart rate and arterial stiffness right after using the e-cigarettes, and then two and four hours later.
In the first half-hour after using e-cigarettes containing nicotine, blood pressure, heart rate and arterial stiffness increased significantly, the findings showed.
Heart rate and arterial stiffness didn't go up when people used e-cigarettes without nicotine, the study found.
The increase in arterial stiffness was temporary. But continued exposure to cigarette smoking can cause a permanent increase in arterial stiffness, Lundback said.
He speculated that the same permanent change in arterial stiffness seen with tobacco cigarettes would also occur with long-term use of e-cigarettes with nicotine.
Despite this potential risk, one specialist believes e-cigarettes are safer than tobacco cigarettes.
"There is no doubt in my mind that e-cigarettes are much safer than real cigarettes," said Dr. Steven Schroeder, a professor of health and health care and director of the Smoking Cessation Leadership Center at the University of California, San Francisco.
The real question is how much worse is vaping than not using an e-cigarette, and how much better is it than smoking regular cigarettes, Schroeder said.
"The estimates of the harm from an e-cigarette compared with a regular cigarette range from 5 percent to as high as 33 percent," he noted.
"Most of the consensus is that it's about 5 to 10 percent as harmful as a regular cigarette," Schroeder said.
But Schroeder doesn't advocate the use of e-cigarettes in most cases.
"Don't use e-cigarettes unless it's the only way you can quit smoking regular cigarettes," he said.
The results of the study were scheduled to be presented Monday at the European Respiratory Society meeting in Milan, Italy. Findings presented at meetings are generally viewed as preliminary until they've been published in a peer-reviewed journal.
For more on e-cigarettes, visit the U.S. National Institute on Drug Abuse.
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