A new study suggests teenagers in the United States are picking up e-cigarettes more frequently.

Some public officials are concerned e-cigarettes are acting as a "gateway drug," leading teens who would have never picked up smoking to try tobacco, the University of Hawaii Cancer Center reported.

A research team found 30 percent of over 1,900 teens surveyed in Hawaii had tried e-cigarettes, and only 17 percent of the population was using e-cigarettes exclusively. These numbers are significant because they are about three times higher than has been reported in larger U.S. studies conducted in 2011 and 2012,

The surveyed teens were 14 and 15 years of age and were given survey questions that assessed "e-cigarette and cigarette use, alcohol and marijuana use and psychosocial risk factors for substance use." Those who used only e-cigarettes were found to be intermediate in levels of risk and protective factors when compared with non-users and teens who smoked both cigarettes and e-cigarettes.

Overall, 12 percent of the participants used both regular and smokeless tobacco, 3 percent used cigarettes only and 68 percent did not smoke at all; additionally, 67 percent considered e-cigarettes to be less dangerous than cigarettes and 96 percent were aware of the existence of e-cigarettes.  

The researchers noted the effects of e-cigarettes are still being widely debated, but also warned parents to remain aware.

"You have to think carefully about the risks and benefits of using either tobacco or nicotine, which is known to be an addictive substance," said Thomas Wills, PhD, the interim director of the UH Cancer Center's Prevention and Control Program. "A lot of teens think it is easy to quit smoking but it isn't true. It's hard for anybody to quit."

The findings were published in a recent edition of the journal Pediatrics.