title: Electronic cigarettes: assessing the efficacy and the adverse effects through a systematic review of published studies.
abstract: BACKGROUND
  To investigate the efficacy and the adverse effects (AEs) of the electronic cigarette, we performed a systematic review of published studies.
  
  
  METHODS
  We selected experimental and observational studies examining the efficacy (as reduction of desire to smoke and/or number of cigarettes smoked and/or quitting or as reduction of nicotine withdrawal symptoms) and the safety of EC (AEs self-reported or clinical/laboratory). The following search engines were used: PubMed, ISI Web of Knowledge and Cochrane Controlled Trials Register.
  
  
  RESULTS
  Finally, six experimental studies and six cohort studies were included. In the prospective 12-month, randomized controlled trial, smoking reduction was documented in 22.3 and 10.3% at Weeks 12 and 52, respectively (P < 0.001 versus baseline). Moreover, two cohort studies reported a reduction in the number of cigarette/day (from 50 to 80%) after the introduction of the EC. 'Mouth and throat irritation', 'nausea', 'headache' and 'dry cough' were the most frequently AEs reported.
  
  
  CONCLUSIONS
  The use of the EC can reduce the number of cigarettes smoked and withdrawal symptoms, but the AEs reported are mainly related to a short period of use. Long-term studies are needed to evaluate the effects of the EC usage after a chronic exposure.
authors.affiliation: Department of Public Health Sciences, School of Medicine, University of Torino, via Santena 5/bis, Turin 10126, Italy.
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Gualano
authors.affiliation: Department of Public Health Sciences, School of Medicine, University of Torino, via Santena 5/bis, Turin 10126, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Passi
authors.affiliation: Department of Public Health Sciences, School of Medicine, University of Torino, via Santena 5/bis, Turin 10126, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Bert
authors.affiliation: Department of Public Health and Infectious Diseases, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: La Torre
authors.affiliation: Department of Public Health Sciences, School of Medicine, University of Torino, via Santena 5/bis, Turin 10126, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Scaioli
authors.affiliation: Department of Public Health Sciences, School of Medicine, University of Torino, via Santena 5/bis, Turin 10126, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Siliquini
mesh_terms: D066300:Electronic Nicotine Delivery Systems / Q000009:adverse effects* / Q000523:psychology; D006801:Humans; D012907:Smoking / Q000453:epidemiology / Q000523:psychology
keywords: e-cigarette; efficacy; electronic device; safety; smoking; tobacco