title: E-cigarette use among US adolescents: secondhand smoke at home matters.
abstract: OBJECTIVE
  To examine the association of family smoking status and exposure to secondhand smoke (SHS) at home with the use of electronic cigarettes among US adolescents, in particular the medication effect of SHS on the association between family smoking status and electronic cigarette use.
  
  
  METHODS
  Data from the 2013 National Youth Tobacco Survey were used and logistic regressions were conducted to model electronic cigarettes use. The mediation effect of SHS was tested using the Sobel-Goodman mediation test.
  
  
  RESULTS
  Overall, 8.1 % of the US adolescents reported ever use of e-cigarettes. Among both the overall population and never-cigarette smokers, adolescents living in smoker households were significantly more likely to report ever use of e-cigarettes (p < 0.05). However, the associations were attenuated after including SHS exposure at home during the past 7 days. SHS exposure at home was positively associated with ever use of e-cigarettes, adjusting for family smoking status (p < 0.05).
  
  
  CONCLUSIONS
  The association between smoking habits of the family and e-cigarette use was mediated through SHS exposure. The promotion of smoke-free home rules may help prevent the uptake of e-cigarettes among teenagers.
authors.affiliation: UW Carbone Cancer Center, University of Wisconsin-Madison, Madison, WI, USA. xzhang86@wisc.edu.
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Mathematica Policy Research, Oakland, CA, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Pu
mesh_terms: D000293:Adolescent; D002648:Child; D003430:Cross-Sectional Studies; D066300:Electronic Nicotine Delivery Systems / Q000706:statistics & numerical data*; D005190:Family; D005260:Female; D006184:Habits; D006801:Humans; D008297:Male; D012907:Smoking / Q000453:epidemiology*; D011795:Surveys and Questionnaires; D062789:Tobacco Products; D014028:Tobacco Smoke Pollution / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology
chemical_list: D014028:Tobacco Smoke Pollution
keywords: Adolescents; Electronic cigarettes; Secondhand smoke exposure