title: Factors associated with e-cigarette use: a national population survey of current and former smokers.
abstract: BACKGROUND
  Few national surveys document the prevalence of e-cigarette use in the U.S. The existing metric to assess current use likely identifies individuals who have recently tried an e-cigarette but do not continue to use the product.
  
  
  OBJECTIVE
  To document the prevalence of e-cigarette ever use, current use, and established use in a nationally representative survey of current and former cigarette smokers in the U.S.
  
  
  METHODS
  A random sample of current and former cigarette smokers completed a web-based survey in June 2013 (n=2,136). Data were analyzed in November 2013. Multivariate logistic regression identified demographic and smoking-related factors associated with each use category. Point estimates with 95% CIs described e-cigarette use behaviors (e.g., preferred brand, purchasing patterns) for each group.
  
  
  RESULTS
  Almost half of respondents had tried e-cigarettes (46.8%), but prevalence of established use remained low (3.8%). Although trial of e-cigarettes was highest among daily smokers, the odds of being an established e-cigarette user were greater for former smokers (OR=3.24, 95% CI=1.13, 9.30, p<0.05). Furthermore, e-cigarette preference and use patterns varied among ever, current, and established users. Established users reported using rechargeable e-cigarettes, having a regular brand, and using e-cigarettes at home and in the workplace at much higher levels than the "current use" metric captures.
  
  
  CONCLUSIONS
  Improved survey measures for e-cigarette use are needed. The identification of established e-cigarette users may provide insight to product features or other individual factors that are associated with sustained use of e-cigarettes.
authors.affiliation: Center for Tobacco Studies, Rutgers School of Public Health, Rutgers University, New Brunswick, New Jersey. Electronic address: d.giovenco@rutgers.edu.
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Giovenco
authors.affiliation: Center for Tobacco Studies, Rutgers School of Public Health, Rutgers University, New Brunswick, New Jersey.
authors.forename: M Jane
authors.initials: MJ
authors.lastname: Lewis
authors.affiliation: Center for Tobacco Studies, Rutgers School of Public Health, Rutgers University, New Brunswick, New Jersey.
authors.forename: Cristine D
authors.initials: CD
authors.lastname: Delnevo
mesh_terms: D000293:Adolescent; D000328:Adult; D003625:Data Collection; D066300:Electronic Nicotine Delivery Systems / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012907:Smoking / Q000453:epidemiology*; D016540:Smoking Cessation / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology; D055815:Young Adult