Researchers at the Schroeder Institute at the American Legacy Foundation, a non-profit Washington group that seeks to address the health effects of tobacco use, analyzed data from more than 6,000 adults who participated in two national surveys.
They found 40.2 percent of U.S. adults have heard of e-cigarettes -- drug-delivery devices that allow smokers to inhale vaporized nicotine in a cigarette-like fashion -- and more than 70 percent said they were less harmful than regular cigarettes.
Current smokers were several times more likely to have tried an e-cigarette than non-smokers, but the researchers said they were not sure why.
"There could be various reasons for this, including that e-cigarettes are perceived as safer than regular cigarettes, are used as cessation devices, or are used to avoid smoke-free indoor air laws," Jennifer Pearson, a research investigator at the institute, said in a statement.
The researchers' study, published in the American Journal of Public Health, found more than 70 percent of U.S. adults said e-cigarettes were less harmful than regular cigarettes.
Since e-cigarettes dispense nicotine, a highly addictive substance, and as yet are unregulated, they raise serious concerns for public health, Legacy officials said in a release.
"Given the poor quality control of these products, consumers are taking unknown risks by using e-cigarettes, with little proven new benefits," said David Abrams, executive director of the Schroeder Institute at Legacy.