title: E-cigarette use is differentially related to smoking onset among lower risk adolescents.
abstract: E-cigarette use has been linked to onset of cigarette smoking among adolescents, but some commentators have suggested that this simply reflects high-risk adolescents being more likely to use e-cigarettes and to smoke. We tested whether the effect of e-cigarette use for smoking onset differs for youth who are lower versus higher on propensity to smoke.
  
  
  
  School-based survey with a longitudinal sample of 1136 students (9th-11th graders, mean age 14.7 years) in Hawaii, initially surveyed in 2013 (T1) and followed up 1 year later (T2). We assessed e-cigarette use, propensity to smoke based on 3 psychosocial factors known to predict smoking (rebelliousness, parental support and willingness to smoke), and cigarette smoking status. Analyses based on T1 never-smokers tested the relation of T1 e-cigarette use to T2 smoking status for participants lower versus higher on T1 propensity to smoke.
  
  
  
  The relation between T1 e-cigarette use and T2 smoking onset was stronger among participants with lower levels of rebelliousness and willingness and higher levels of parental support. A multiple logistic regression analysis with T2 smoking as the criterion tested the cross-product of T1 e-cigarette use and T1 smoking propensity score; the interaction (OR=0.88, p=0.01) indicated a significantly larger effect for smoking onset among lower risk youth.
  
  
  
  The results indicate e-cigarette use is a risk factor for smoking onset, not just a marker of high risk for smoking. This study provides evidence that e-cigarettes are recruiting lower risk adolescents to smoking, which has public health implications.
authors.affiliation: University of Hawaii, Cancer Center, Honolulu, Hawaii, USA.
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Wills
authors.affiliation: Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA.
authors.forename: James D
authors.initials: JD
authors.lastname: Sargent
authors.affiliation: Center for Health, Intervention & Prevention, University of Connecticut, Storrs, Connecticut, USA.
authors.forename: Frederick X
authors.initials: FX
authors.lastname: Gibbons
authors.affiliation: University of Hawaii, Cancer Center, Honolulu, Hawaii, USA.
authors.forename: Ian
authors.initials: I
authors.lastname: Pagano
authors.affiliation: Office of Public Health Studies, University of Hawaii at Manoa, Honolulu, Hawaii, USA.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Schweitzer
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D066300:Electronic Nicotine Delivery Systems; D005260:Female; D006801:Humans; D008297:Male; D012306:Risk; D012574:Schools; D012907:Smoking; D013334:Students; D011795:Surveys and Questionnaires; D062789:Tobacco Products
keywords: Addiction; Electronic nicotine delivery devices; Priority/special populations