The devices -- battery-powered metal cartridges that simulate the effect of smoking by heating nicotine-containing liquid into vapor -- can be helpful to smokers trying to kick the habit, says researcher Konstantinos Farsalinos, MD, of the Onassis Cardiac Surgery Center in Athens, Greece.
"Considering the hazards associated with cigarette smoking, currently available data suggest that electronic cigarettes are far less harmful, and substituting tobacco with electronic cigarettes may be beneficial to health," he says.
Speaking here at the annual meeting of the European Society of Cardiology, Farsalinos acknowledges that the study was short and small -- only 22 people were studied immediately before and after using the devices.
Another small study shows that e-cigarettes may have short-term harmful effects on lung function, he says.
Many more people have to be studied for much longer before any firm conclusions can be made about the safety of electronic cigarettes, Farsalinos says.
Still, e-cigarettes are the only smoking cessation aids that satisfy both sides of addiction: the chemical craving for nicotine and "the psychological addiction that comes from having something in your hand, lighting it, and inhaling and exhaling it," he says. "Preliminary studies show this [two-pronged attack] helps people to quit."
Millions Use Electronic Cigarettes
Invented by a Chinese pharmacist in 2003, electronic cigarettes are now used by millions worldwide as an alternative to smoking. But the devices are not regulated, and the World Health Organization has called for studies on their effects on human health.
In the new study, the researchers compared the heart function of 20 daily smokers before and after smoking one tobacco cigarette to that of 22 e-cigarette users before and after using the device for seven minutes. The people studied were healthy and varied in age from 25 to 45.
American Heart Association spokesman Russell Luepker, MD, of the University of Minnesota in Minneapolis, says that because they "light up," electronic cigarettes may be preferred over other smoking cessation aids by some people trying to quit.
It’s not surprising they are less harmful than the real thing, he says. "The e-cigarette has the advantage of not having the thousands of other chemicals, besides nicotine, that a real cigarette has," he says.
"I don't think it's conclusive but there's no doubt if you expose someone to fewer bioactive chemical compounds there is going to be less effect on the heart," Luepker says. But they should only be used as a temporary bridge while quitting smoking, he says.
The e-cigarettes used in the study contained 11 milligrams per milliliter of nicotine (Nobacco, USA Mix) in the liquid. That’s a "moderate" amount, according to Farsalinos, who says they can contain up to 23 milligrams per milliliter of nicotine.
Many laboratory analyses have shown electronic cigarettes do not contain carcinogens, he says. But even in studies where formaldehyde and other carcinogens were found, the levels detected were 500 to 1,400 times less than the amount present in one tobacco cigarette, Farsalinos says.
"You would have to use e-smokes for six to eight months to get the amount of chemical present in a single tobacco cigarette," he says.
An electronic cigarette kit typically costs from $30 to $200.
These findings were presented at a medical conference. They should be considered preliminary, as they have not yet undergone the "peer review" process, in which outside experts scrutinize the data prior to publication in a medical journal.