E-cigarettes and National Adolescent Cigarette Use: 2004–2014 Lauren M. Dutra, ScD,a Stanton A. Glantz, PhDa, b BACKGROUND: E-cigarette use is rapidly increasing among adolescents in the United States, abstract with some suggesting that e-cigarettes are the cause of declining youth cigarette smoking. We hypothesized that the decline in youth smoking changed after e-cigarettes arrived on the US market in 2007. METHODS: Data were collected by using cross-sectional, nationally representative school- based samples of sixth- through 12th-graders from 2004–2014 National Youth Tobacco Surveys (samples ranged from 16 614 in 2013 to 25 324 in 2004). Analyses were conducted by using interrupted time series of ever (≥1 puff) and current (last 30 days) cigarette smoking. Logistic regression was used to identify psychosocial risk factors associated with cigarette smoking in the 2004–2009 samples; this model was then applied to estimate the probability of cigarette smoking among cigarette smokers and e-cigarette users in the 2011–2014 samples. RESULTS: Youth cigarette smoking decreased linearly between 2004 and 2014 (P = .009 for ever smoking and P = .05 for current smoking), with no significant change in this trend after 2009 (P = .57 and .23). Based on the psychosocial model of smoking, including demographic characteristics, willingness to wear clothing with a tobacco logo, living with a smoker, likelihood of smoking in the next year, likelihood of smoking cigarettes from a friend, and use of tobacco products other than cigarettes or e-cigarettes, the model categorized <25% of current e-cigarette–only users (between 11.0% in 2012 and 23.1% in 2013) as current smokers. CONCLUSIONS: The introduction of e-cigarettes was not associated with a change in the linear decline in cigarette smoking among youth. E-cigarette–only users would be unlikely to have initiated tobacco product use with cigarettes. NIH WHAT’S KNOWN ON THIS SUBJECT: E-cigarette use is a Center for Tobacco Control Research and Education, and bDepartment of Medicine, University of California San Francisco, San Francisco, California rapidly increasing among adolescents in the United States, with some suggesting increased e-cigarette Dr Dutra designed the study, carried out analyses, drafted the initial manuscript, and revised use contributes to the decline in cigarette smoking. the manuscript; Dr Glantz conceptualized and designed the study, carried out analyses, and critically reviewed and revised the manuscript; and both authors approved the fi nal manuscript WHAT THIS STUDY ADDS: The introduction of as submitted. e-cigarettes was not associated with a change in Dr Dutra’s current affi liation is RTI International, Berkeley, CA the linear decline in cigarette smoking among youth but is expanding overall use. E-cigarette–only users This research was conducted with Centers for Disease Control and Prevention data. The would be unlikely to have initiated tobacco product views expressed here do not necessarily refl ect the views of Centers for Disease Control and use with cigarettes. Prevention. DOI: 10.1542/peds.2016-2450 Accepted for publication Nov 7, 2016 Address correspondence to Stanton A. Glantz, PhD, Center for Tobacco Control Research and To cite: Dutra LM and Glantz SA. E-cigarettes and National Education, Room 366 Library, 530 Parnassus Ave, University of California, San Francisco, CA 94143- Adolescent Cigarette Use: 2004–2014. Pediatrics. 1390. E-mail: [email protected] 2017;139(2):e20162450 Downloaded from www.aappublications.org/news by guest on September 23, 2021 PEDIATRICS Volume 139 , number 2 , February 2017 :e 20162450 ARTICLE Between 2011 and 2014, US recent declines in youth smoking, samples of 15 664 in 2013 to 24 690 adolescent e-cigarette use rapidly and some have suggested that in 2004. increased, with 13.4% of high school restricting e-cigarettes may harm students and 3.9% of middle school public health.27, 28 Two analyses of the Measures students reporting past-30-day use effects of enacting laws that prohibit Cigarette Smoking in 2014. In 2014, between 13% the sales of e-cigarettes to youth aged “Ever smokers” were those who and 40% of middle and high school <18 years reported that these laws responded “yes” to “Have you ever e-cigarette users in Connecticut, 1 the were associated with increases of tried cigarette smoking, even 1 or 2 United States, 2 and Canada 3 reported 0.9% 27 and 0.8% 28 in the absolute puffs?” “Current smokers” reported using e-cigarettes containing prevalence of cigarette smoking the use of cigarettes during the past nicotine. (These reports may among adolescents. Neither of these 30 days on at least 1 day. We also underestimate nicotine exposure reports measured e-cigarette use. examined number of days smoked because 8%–12% of students In contrast, results from Southern in the past 30 days among current responded “don’t know” to questions California indicated that e-cigarette smokers (1–2 days, 3–5 days, 6–9 about e-cigarette contents, 1, 2, 4 and use is occurring in adolescents who days, 10–19 days, 20–29 days, or all e-cigarettes labeled “nicotine-free” would not otherwise have used 30 days). often contain nicotine. 5, 6) Nicotine tobacco products. 29 We used the exposure during adolescence can 2004–2014 National Youth Tobacco E-cigarette Use affect memory, attention, and Survey (NYTS) to assess whether E-cigarettes were first included in the emotional regulation. 7 E-cigarette the decline in adolescent cigarette NYTS in 2011. From 2011 through aerosol has been linked to cell smoking changed after e-cigarettes 2014, participants were “ever damage, 8 lung inflammation, asthma, 9 entered the US market (around e-cigarette users” if they replied and respiratory infections. 8, 10 Among 200730 – 33) and the extent to which “electronic cigarettes or e-cigarettes” Korean 10th- to 12th-grade never e-cigarettes are attracting youth who to “Which of the following tobacco cigarette smokers, current (30-day) would be unlikely to begin nicotine products have you ever tried, even e-cigarette users were more likely use with cigarettes on the basis of just one time?” Participants were to have been diagnosed with asthma known psychosocial predictors of the defined as “current e-cigarette and had 15.4 (95% confidence onset of cigarette use. users” if they reported the use of interval [CI]: 5.1–45.7) times the e-cigarettes during the past 30 days odds of missing ≥4 days of school on at least 1 day. in the past year due to asthma METHODS than did never e-cigarette users. 11 Never smokers with a missing Sample Adolescents who use e-cigarettes, response for 30-day smoking were but not cigarettes, show fewer We used data from the 2004, 2006, considered noncurrent smokers. of the psychosocial risk factors 2009, 2011, 2012, 2013, and 2014 Never e-cigarette users with a associated with smoking than do school-based paper-and-pencil missing response for 30-day cigarette-smoking adolescents (but NYTS, a repeated, cross-sectional, e-cigarette use were considered more than never e-cigarette users), nationally representative, 3-stage noncurrent e-cigarette users. such as rebelliousness, sensation cluster (counties, schools, grades) seeking, and prevalence of peer sample of sixth- to 12th-graders Other Tobacco Use smoking.12, 13 Longitudinal research (ages 9–21). 34 School response We included ever and current use consistently shows that never- rates ranged from 75% in 2013 to of all tobacco products besides smoking adolescent e-cigarette users 93% in 2004, and student response cigarettes and e-cigarettes that were are more likely than never e-cigarette rates varied from 88% in 2004, assessed in every NYTS conducted users to subsequently start smoking 2006, and 2011 to 93% in 2009. 34 between 2004 and 2014: chewing cigarettes. 14 – 18 Participants with missing values tobacco, snuff, or dip; cigars, for demographic characteristics, cigarillos, or little cigars; tobacco in At the same time that e-cigarette use psychosocial predictor variables, ever a pipe; or bidis. Respondents who was increasing, cigarette smoking or current smoking, e-cigarette use reported ever using any of these among youth declined, 2, 19 leading (available in 2011–2014 surveys), products (ie, other than cigarettes some to suggest that e-cigarettes are or use of tobacco products other or e-cigarettes) were considered replacing conventional cigarettes than cigarettes or e-cigarettes were “ever other” tobacco users, and those among youth. 20 –22 Researchers23 and excluded from this analysis (6.6% in who reported using them in the past popular media 24 – 26 have suggested 2004 to 10.1% in 2009 and 2011 who 30 days were considered “current that e-cigarettes are contributing to were missing data), yielding analytic other” tobacco users. The prevalence Downloaded from www.aappublications.org/news by guest on September 23, 2021 2 DUTRA and GLANTZ of other tobacco use did not change Analysis factor = 23.0), we did not adjust for significantly between 2004 and demographic characteristics in the Centers for Disease Control and 2014, averaging 5.1% for ever use meta-regression. Prevention–provided stratification and 4.4% for current use (P for trend variables were included to adjust with time: .26 and .81, respectively). Psychosocial Model To Predict Cigarette for clustered sampling techniques. Smoking Psychosocial Risk Factors Centers for Disease Control and We developed a psychosocial model Prevention–provided weights were We examined psychosocial risk of cigarette smoking to estimate the included to adjust for nonresponse factors for cigarette smoking or probability that e-cigarette users and to match sample characteristics e-cigarette use identified in previous would have initiated nicotine use to national estimates. 35 We used research that were also available with cigarettes. We hypothesized SAS surveyfreq (SAS Institute, Cary, for the 2004–2014 NYTS data.