Young adults who use electronic cigarettes are more than four times as likely to begin smoking tobacco cigarettes within 18 months as their peers who do not vape, according to new research. The findings demonstrate that e-cigarettes are serving as a gateway to traditional smoking, contrary to their purported value as a smoking cessation tool. The study is the first nationally representative survey that followed for more than a year people 18 to 30 years old who were initially nonsmokers.