New research suggests that teens who smoke e-cigarettes are more likely to smoke traditional cigarettes later.

Researchers at the University of Pittsburgh and Dartmouth-Hitchcock Norris Cotton Cancer Center found that teens and young adults who "vape" are more likely to move on to traditional cigarettes than those who don't use the electronic devices, Reuters reported.

The results, which were published online today and sponsored by the National Cancer Institute, scheduled for the November print issue of JAMA Pediatrics, are particularly timely as the U.S. Food and Drug Administration considers how to regulate e-cigarettes, which are easier for adolescents to purchase and, in many respects, more attractive to young people than traditional cigarettes.

"E-cigarettes are not subject to many laws that regulate traditional cigarettes, such as age limits on sales, taxation and labeling requirements. They also come in youth-oriented flavorings that laws have limited in traditional cigarettes, such as apple bubble gum and chocolate candy cane," Brian A. Primack, lead author of the study and assistant vice chancellor for health and society in Pitt's Schools of the Health Sciences, said in a statement.

For the study, researchers collected and analyzed data on a national sample of nearly 700 16- to 26-year-old nonsmokers surveyed in 2012 and again in 2013 through the Dartmouth Media, Advertising, and Health Study, Newsweek reported.  All participants were considered "non-susceptible" to initiating traditional cigarette smoking at the beginning of the study, because they had responded "definitely no" when asked if they would try a cigarette offered by a friend or believed they would smoke a cigarette within the next year.

They found that by the next year, 38 percent of the baseline e-cigarette users had initiated traditional cigarette smoking. In comparison, only 10 percent of the youths who were not baseline e-cigarette users started smoking traditional cigarettes.

"These differences remained statistically significant and robust even when we controlled for multiple known risk factors for initiating cigarette smoking, such as age, sex, race, ethnicity, socioeconomic status, sensation seeking, parental smoking and friend smoking," Primack said.

Regulating e-cigarettes is particularly controversial because they are sometimes used as harm reduction tools by established smokers.

The findings are detailed in the online version of JAMA Pediatrics.