title: Electronic nicotine delivery system (electronic cigarette) awareness, use, reactions and beliefs: a systematic review.
abstract: OBJECTIVE
  We sought to systematically review the literature on electronic nicotine delivery systems (ENDS, also called electronic cigarettes) awareness, use, reactions and beliefs.
  
  
  METHODS
  We searched five databases for articles published between 2006 and 1 July 2013 that contained variations of the phrases 'electronic cigarette', 'e-cigarette' and 'electronic nicotine delivery'.
  
  
  METHODS
  Of the 244 abstracts identified, we excluded articles not published in English, articles unrelated to ENDS, dissertation abstracts and articles without original data on prespecified outcomes.
  
  
  METHODS
  Two reviewers coded each article for ENDS awareness, use, reactions and beliefs.
  
  
  RESULTS
  49 studies met inclusion criteria. ENDS awareness increased from 16% to 58% from 2009 to 2011, and use increased from 1% to 6%. The majority of users were current or former smokers. Many users found ENDS satisfying, and some engaged in dual use of ENDS and other tobacco. No longitudinal studies examined whether ENDS serve as 'gateways' to future tobacco use. Common reasons for using ENDS were quitting smoking and using a product that is healthier than cigarettes. Self-reported survey data and prospective trials suggest that ENDS might help cigarette smokers quit, but no randomised controlled trials with probability samples compared ENDS with other cessation tools. Some individuals used ENDS to avoid smoking restrictions.
  
  
  CONCLUSIONS
  ENDS use is expanding rapidly despite experts' concerns about safety, dual use and possible 'gateway' effects. More research is needed on effective public health messages, perceived health risks, validity of self-reports of smoking cessation and the use of different kinds of ENDS.
authors.affiliation: Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Jessica K
authors.initials: JK
authors.lastname: Pepper
authors.affiliation: Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina, USA Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina, USA.
authors.forename: Noel T
authors.initials: NT
authors.lastname: Brewer
mesh_terms: D001290:Attitude; D066300:Electronic Nicotine Delivery Systems / Q000706:statistics & numerical data; D004581:Electronics; D006801:Humans; D009042:Motivation; D009538:Nicotine / Q000008:administration & dosage*; D016540:Smoking Cessation; D000074606:Smoking Prevention; D062789:Tobacco Products
chemical_list: D009538:Nicotine
keywords: Electronic nicotine delivery devices; Harm Reduction; Non-cigarette tobacco products