title: Is vaping a gateway to smoking: a review of the longitudinal studies.
abstract: BACKGROUND
  The use of e-cigarettes (ECs) is rising globally. There is concern that e-cigarette may actually lead to smoking, especially amongst adolescents.
  
  
  OBJECTIVE
  To perform a comprehensive review of literature reporting the longitudinal effects of e-cigarette use on onset of smoking among adolescents and young adults.
  
  
  METHODS
  A search was conducted using PubMed, Google Scholar, Scopus, and Web of Science in February 2016 to identify the studies containing data on EC use among adolescents and young adults (age<30 years). We then narrowed our search to only include longitudinal studies with data on EC and conventional cigarette smoking among this population.
  
  
  RESULTS
  Four longitudinal studies were identified that analyzed the use of ECs and smoking at both baseline and follow-ups in the target population. These studies demonstrated that EC use is associated with an increase in combustible cigarette smoking, even amongst the adolescents who were not susceptible to smoking.
  
  
  CONCLUSIONS
  This review highlights the strong evidence that not only are ECs are not an effective tool for smoking cessation among adolescents, they actually are associated with higher incidence of combustible cigarette smoking. Policy makers need to recognize of the insidious nature of this campaign by the tobacco industry and design policies to regulate it.
authors: Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR,USA.
authors: Kshitij
authors: http://orcid.org/0000-0002-3873-2720
authors: K
authors: Chatterjee
authors: Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR,USA.
authors: Bashar
authors: B
authors: Alzghoul
authors: Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR,USA.
authors: Ayoub
authors: A
authors: Innabi
authors: Department of Internal Medicine, University of Arkansas for Medical Sciences, Little Rock, AR,USA.|Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR,USA.
authors: Nikhil
authors: N
authors: Meena
keywords: adolescent; electronic cigarettes; smoking/psychology