Just over three percent of US adolescents had ever tried an e-cigarette in 2011, and that more than doubled to 6.5 percent in 2012, said the research in JAMA Pediatrics, a journal of the American Medical Association.
Similarly, 1.1 percent of middle and high school students said they currently used e-cigarettes in 2011, a figure that rose to two percent in 2012.
Youths who had tried e-cigarettes were more likely to experiment with conventional cigarettes, and were more likely to be current cigarette smokers than kids who had not tried them, said the study.
The research was based on middle and high school students who filled out the National Youth Tobacco Survey, including more than 17,500 in 2011 and some 22,500 in 2012.The nature of the study did not allow researchers to determine whether kids were trying e-cigarettes first and then moving on to conventional cigarettes.
However, "our results suggest that e-cigarettes are not discouraging use of conventional cigarettes," said the study, led by Lauren Dutra and Stanton Glantz of the Center for Tobacco Research and Education at the University of California, San Francisco.
Since e-cigarettes are not subject to the same advertising and marketing restrictions as tobacco, some health experts are concerned that they could be tempting a new generation of addicts.
The US Food and Drug Administration, which gained oversight of tobacco products in 2009, is currently considering whether to regulate e-cigarettes.
"While much remains to be learned about the public health benefits and/or consequences of ENDS (electronic nicotine delivery systems) use, their exponential growth in recent years, including their rapid uptake among youths, makes it clear that policy makers need to act quickly," said an accompanying editorial by Frank Chaloupka of the University of Illinois at Chicago.