E-Cigarette Use and Subsequent Cigarette Initiation and Sustained Use Among Youth, U.S., 2015-2017.

Purpose: Using cross-sectional data, we measured the association between electronic cigarette (e-cigarette) use and subsequent initiation and sustained use of cigarettes among U.S. youth.

Methods: Data were pooled from the 2015-2017 National Youth Tobacco Survey, a school-based survey of U.S. students in grades 6-12. Questions on current age and age of first use of different tobacco products (cigarettes, e-cigarettes, cigars, and smokeless tobacco) were used to ascertain the temporal sequence of tobacco product use. The pooled study population was 52,579 youth who 5 years before the survey had never smoked cigarettes. E-cigarette users were defined as those who used e-cigarettes before or without ever smoking cigarettes. Cigarette smoking was assessed with the following measures: ever smoking a cigarette at any time within the past 5 years and sustained smoking (smoked ≥1 year ago and within past 30 days). Adjusted odds ratios (AORs) were calculated, controlling for other tobacco product use and sociodemographics.

Results: Among never cigarette smokers as of 5 years before the survey, 17.4% used e-cigarettes, and 15.6% first smoked within the past 5 years. Compared with those who did not use e-cigarettes, those who used e-cigarettes had higher odds of ever smoking cigarettes within the past 5 years (AOR = 2.73) and had higher odds of sustained smoking (AOR = 1.55; all p < .05).

Conclusions: E-cigarette use is associated with subsequent initiation and sustained use of cigarettes among youth. Efforts are warranted to reduce youth use of all tobacco products, including e-cigarettes.