title: A longitudinal study of electronic cigarette use among a population-based sample of adult smokers: association with smoking cessation and motivation to quit.
abstract: OBJECTIVE
  Increasingly popular electronic cigarettes (e-cigarettes) may be the most promising development yet to end cigarette smoking. However, there is sparse evidence that their use promotes cessation. We investigated whether e-cigarette use increases smoking cessation and/or has a deleterious effect on quitting smoking and motivation to quit.
  
  
  METHODS
  Representative samples of adults in 2 US metropolitan areas were surveyed in 2011/2012 about their use of novel tobacco products. In 2014, follow-up interviews were conducted with 695 of the 1,374 baseline cigarette smokers who had agreed to be re-contacted (retention rate: 51%). The follow-up interview assessed their smoking status and history of electronic cigarette usage. Respondents were categorized as intensive users (used e-cigarettes daily for at least 1 month), intermittent users (used regularly, but not daily for more than 1 month), and non-users/triers (used e-cigarettes at most once or twice).
  
  
  RESULTS
  At follow-up, 23% were intensive users, 29% intermittent users, 18% had used once or twice, and 30% had not tried e-cigarettes. Logistic regression controlling for demographics and tobacco dependence indicated that intensive users of e-cigarettes were 6 times more likely than non-users/triers to report that they quit smoking (OR: 6.07, 95% CI = 1.11, 33.2). No such relationship was seen for intermittent users. There was a negative association between intermittent e-cigarette use and 1 of 2 indicators of motivation to quit at follow-up.
  
  
  CONCLUSIONS
  Daily use of electronic cigarettes for at least 1 month is strongly associated with quitting smoking at follow-up. Further investigation of the underlying reasons for intensive versus intermittent use will help shed light on the mechanisms underlying the associations between e-cigarette use, motivation to quit, and smoking cessation.
authors.affiliation: Center for Survey Research, University of Massachusetts, Boston, MA lois.biener@umb.edu.
authors.forename: Lois
authors.initials: L
authors.lastname: Biener
authors.affiliation: Center for Survey Research, University of Massachusetts, Boston, MA.
authors.forename: J Lee
authors.initials: JL
authors.lastname: Hargraves
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D066300:Electronic Nicotine Delivery Systems / Q000706:statistics & numerical data*; D005260:Female; D006306:Health Surveys; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009042:Motivation; D012106:Research; D012907:Smoking / Q000523:psychology; D016540:Smoking Cessation / Q000379:methods* / Q000523:psychology*; D000074606:Smoking Prevention; D055815:Young Adult