Are e-cigarettes a gateway to using traditional cigarettes?

E-cigarettes are in fact a gateway to smoking traditional cigarettes, a recent study says.

The study, published in the journal JAMA Pediatrics, investigated the relationship between e-cigarette and conventional cigarette use among adolescents. Lead author Lauren Dutra concluded that the "use of e-cigarettes does not discourage, and may encourage, conventional cigarette use among U.S. adolescents," in a statement.

But some critics argue that their findings do not back up their statement.

"The authors seem to have an axe to grind," said Dr. Michael Siegel, a professor of community health sciences at Boston University School of Public Health, in a Reuters report. "I could equally argue that what this study shows is that people who are heavy smokers are attracted to e-cigarettes because they are looking to quit."

The University of California San Francisco's Center for Tobacco Control Research and Education collected data on 40,000 adolescents using a national survey carried out by the Centers for Disease Control and Prevention.

The data showed that since 1965, cigarette use has dropped from 43 to 18 percent. Despite that positive note, over 3,200 young people a day under the age of 18 try their first cigarette, a recent government report found, and the use of e-cigarettes by adolescents doubled between 2011 and 2012. The authors note that this study did not follow the subjects over a long time period, and so it's hard to say which came first, e-cigarette use or traditional cigarette use.

But, researchers did add that about 20 percent of middle school students and about 7 percent of high school students who have used e-cigarettes had never smoked regular cigarettes - meaning that some kids are introduced to the addictive drug nicotine through e-cigarettes. And as of 2012, 1.78 million U.S. students have used the battery-powered device, according to the CDC.

E-cigarettes deliver nicotine and other chemicals in a vapor form and are marketed as safer to use than regular cigarettes and a way to quit smoking. It is unregulated by the Food and Drug Administration, but the device is gaining popularity among U.S. youths.