They are not subject to the same regulations as tobacco cigarettes, and some health experts are concerned that their use will balloon in the coming years, particularly among vulnerable youths worldwide.
The JAMA study was based on a pool of 2,530 students, with an average age of 14, from 10 public high schools in Los Angeles.
At the beginning of the study, all reported never having smoked tobacco — cigarettes, cigars or hookahs — and 222 said they tried e-cigarettes.
Students answered surveys after six months and one year, describing their use of any combustible tobacco products. Those who used e-cigarettes were more likely to report smoking cigarettes, cigars or hookahs during the study period than were students who did not.
After six months, 31 percent of e-cigarette users tried other forms of tobacco, compared with 8 percent of nonvapers.
Some experts stressed that the findings do not show a causal link.
"The new study does not show that vaping leads to smoking," said Peter Hajek, a professor of clinical psychology at the University of London. "It just shows that people who are attracted to e-cigarettes are the same people who are attracted to smoking."
"Despite the headlines this study will generate, there is no evidence to suggest that experimentation with vaping among nonsmokers leads to even regular vaping, let alone to smoking," he said.