Smoking behaviors and intentions among current e-cigarette users, cigarette smokers, and dual users: A national survey of U.S. high school seniors.

E-cigarette use among adolescents has increased significantly in recent years, but it remains unclear whether cigarette smoking behaviors and intentions for future cigarette smoking differ among current (i.e., 30-day) non-users, only e-cigarette users, only cigarette smokers, and dual users. A nationally representative sample of 4385 U.S. high school seniors were surveyed during the spring of their senior year via self-administered questionnaires in 2014. An estimated 9.6% of U.S. high school seniors reported current e-cigarette use only, 6.3% reported current cigarette smoking only, and 7.2% reported current dual use of e-cigarettes and cigarette smoking. There were no significant differences between current only cigarette smokers and dual users in the odds of early onset of cigarette smoking, daily cigarette smoking, intentions for future cigarette smoking, friends' cigarette smoking behaviors, attempts to quit cigarette smoking, or the inability to quit cigarette smoking. Adolescents who only used e-cigarettes had higher odds of intentions for future cigarette smoking in the next 5years (AOR=2.57, 95% CI: 1.21-5.24) than current non-users. Dual users and only cigarette smokers had higher odds of cigarette smoking behaviors and intentions for future cigarette smoking than non-users or only e-cigarette users. Adolescents who engage in current dual use have cigarette smoking behaviors and intentions for future cigarette smoking that more closely resemble cigarette smokers than e-cigarette users. Adolescents who only use e-cigarettes have higher intentions to engage in future cigarette smoking relative to their peers who do not engage in e-cigarette use or cigarette smoking.