Comparison of e-cigarette use prevalence and frequency by smoking status among youth in the United States, 2014-19

Background and aims Reports of youth e-cigarette use often do not disaggregate by underlying smoking status. This study compared annual 2014-19 youth estimates of past 30-day e-cigarette use prevalence and frequency by smoking status in the United States. Design Nationally representative, cross-sectional, school-based survey [National Youth Tobacco Surveys (NYTS)]. General linear models accounting for complex survey design compared e-cigarette use prevalence by smoking status by year, overall and stratified by frequency, separately for high school (HS) and middle school (MS) students. The 2019 survey was analyzed separately because of its change in survey methodology. Setting MSs and HSs in the United States. Participants A total of 116 704 students from 1268 schools, ages 9-19. Measurements Students self-reported (paper 2014-18, electronic 2019) ever and past 30-day (current) use of e-cigarettes and cigarettes, as well as frequent use (20-30 days of month). Findings From 2014 to 2018, current e-cigarette use prevalence increased among never, current and former smokers in HS, but only among never and current smokers in MS (each P-value < 0.001). E-cigarette use increases for current HS smokers were primarily among frequent e-cigarette users. In 2018, the absolute number of HS frequent users who were never or former smokers (420 000 combined) surpassed current smokers (370 000). In 2019, current e-cigarette use prevalence for never, former and current smokers was 17.5% [95% confidence interval (CI) = 16.0-19.0], 53.6% (95% CI = 45.2-61.9) and 85.8% (95% CI = 81.6-89.9) for HS students, respectively, and 6.8% (95% CI = 5.9-7.7), 40.8% (95% CI = 34.7-47.0) and 78.0% (95% CI = 71.9-84.2) for MS students. That year, the number of HS never (420 000) and former smokers (570 000) using e-cigarettes frequently eclipsed that of current smokers (390 000). Conclusions E-cigarette use prevalence and frequency among youth vary by smoking status, with highest levels of use among current smokers. However frequent e-cigarette use among never smokers and former smokers has increased.