Cigarette smoking is the leading cause of preventable death in the United States (US), resulting in nearly 480,000 deaths per year (US Department of Health and Human Services, n.d.). Many cigarette smokers initiate during adolescence (US Department of Health and Human Services, 2012a). Early onset of cigarette smoking is related to more adverse health outcomes (US Department of Health and Human Services, n.d.; US Department of Health and Human Services, 2012a; Prizment et al., 2014; Kenfield et al., 2008) and nicotine dependence (US Department of Health and Human Services, n.d.; US Department of Health and Human Services, 2012a). As such, preventing and reducing cigarette smoking among adolescents is a public health priority, and examining patterns and trends in the prevalence of cigarette smoking among younger and older adolescents, separately, is relevant to the same.

In the past two decades, several initiatives at the federal level have been enacted to prevent and reduce cigarette smoking, particularly among youth. These regulatory initiatives include: (1) the Master Settlement Agreement (MSA), signed in late 1998 (Cutler et al., 2002); (2) the Family Smoking Prevention and Tobacco Control Act (TCA) of 2009 (Husten and Deyton, 2013); (3) the Patient Protection and Affordable Care Act (ACA) of 2010 (Berman, 2011); and (4) raising the federal age requirement for purchasing tobacco from 18 to 21 in 2019 (Dobbs et al., 2021). Together, these initiatives allocated billions of dollars in funding to cigarette smoking prevention, cessation, and education efforts (Cutler et al., 2002; Clark et al., 2011; Graham, 2020) and, in so doing, built a comprehensive tobacco control framework on federal, state, and local-levels. In the decade between the first MSA payment to the states ($4.5 billion in 2000) (Clark et al., 2011) and the TCA (2009), past 30-day cigarette smoking prevalence declined 41% among middle and high school students (combined) across the US (Arrazola et al., 2010), supporting the impact that various MSA activities had on youth (e.g., marketing restrictions; communication campaigns) (Cutler et al., 2002; Clark et al., 2011; Graham, 2020). From 2009 to 2013, past 30-day cigarette smoking declined 47.5% among youth (Arrazola et al., 2010; Arrazola et al., 2014), suggesting this short-term impact was sustained and bolstered by the TCA and ACA. These declines slowed markedly in 2014 (Creamer et al., 2021; Dutra and Glantz, 2017).

Electronic cigarettes (e-cigarettes) are the most used tobacco product among middle and high school students (Arrazola et al., 2015), surpassing cigarette smoking for the first time in US history in 2014, and remaining so through 2021 (Park-Lee, 2021). The impact of e-cigarettes on adolescent cigarette smoking is a subject of discussion among public health researchers and policymakers (Samet and Barrington-Trimis, 2021). E-cigarettes first appeared on the US market in 2007 and were initially meant to be a cigarette alternative and method of smoking cessation for adults (US Department of Health and Human Services, 2016). However, for youth, studies show that e-cigarette use increases risk for subsequent initiation of cigarette smoking (Soneji et al., 2017; Khouja et al., 2021; Baenziger et al., 2021; Yoong et al., 2022; Chan et al., 2021), even among those who exhibit fewer risk factors for smoking (Wills et al., 2017; Owotomo et al., 2020; Berry et al., 2019). The impact of adolescent e-cigarette use on the onset and progression in cigarette smoking has been dubbed the “gateway effect.” (Pierce et al., 2021a) Others propose that e-cigarettes have a “diversion effect” by which experimentation with e-cigarettes “entirely prevents some adolescents from ever using conventional cigarettes.” (Selya and Foxon, 2021)

Per Pierce et al. (Pierce et al., 2021a), evidence of the “gateway effect” considered on a population level could be supported not only by an increase in the prevalence of adolescent cigarette smoking after the proliferation of e-cigarette use, but also by a reduction in the rate of decline of cigarette smoking (Creamer et al., 2021). Alternatively, any increase in the rate of decline of cigarette smoking after the proliferation of e-cigarette use would provide support for a “diversion effect.” (Pierce et al., 2021a) Employing methods used in a prior Surgeon General's Report on young people's tobacco use (US Department of Health and Human Services, 2012a), we consider this population-based (Shahab et al., 2022) approach to understanding and documenting the population impact of the “diversion” and/or “gateway” effects on the prevalence of past 30-day adolescent cigarette smoking in recent years.

The aims of our study are three-fold. First, we describe trends in the observed prevalence of past 30-day cigarette smoking, using nationally representative (NYTS) data from 2002 to 2019. Second, we compare trends in the prevalence of past 30-day cigarette smoking before and after the onset of the “e-cigarette era,” in 2014. Finally, informed by trends observed before 2014, we predict trends in past 30-day cigarette smoking prevalence after 2014, to represent trends in cigarette smoking that would have been expected in the absence of the “e-cigarette era.” Additionally, we quantify these prevalence figures to calculate the possible “gateway” or “divergence” effect of the e-cigarette era on adolescent cigarette smoking. Furthermore, we consider middle school (6th–8th grade) and high school (9th–12th grade) students in stratified analyses.