title: Vulnerability to smoking after trying a single cigarette can lie dormant for three years or more.
abstract: OBJECTIVE
  To examine the development of smoking behaviour among adolescents who, at age 11, had tried cigarettes just once.
  
  
  METHODS
  A five-year prospective study.
  
  
  METHODS
  36 schools in South London, England.
  
  
  METHODS
  A socioeconomically and ethnically diverse sample of students completed questionnaires annually from age 11-16. A total of 5863 students took part, with an annual response rate ranging from 74-85%. 2041 (35%) provided smoking status data every year.
  
  
  METHODS
  Current smoking (smoking sometimes or more often) for the first time. Cotinine assays provided biochemical verification of smoking status.
  
  
  RESULTS
  Students who at age 11 reported having tried smoking cigarettes just once (n = 260), but were not smoking at the time, were more likely to take-up smoking at a later age than those that had not tried smoking (n = 1719), even after a gap of up to three years of not smoking. The odds of starting to smoke at age 14 were 2.1 times greater (95% confidence interval 1.2 to 3.5) in the age 11 "one time triers" than the "non-triers", even once sex, ethnicity, deprivation, parental smoking and conduct disorder were adjusted for.
  
  
  CONCLUSIONS
  This is the first clear demonstration of a "sleeper effect" or period of dormant vulnerability. Our findings have implications for understanding the development of cigarette use and for policies to reduce smoking in young people. Preventing children from trying even one cigarette may be important, and the design of interventions should recognise adolescents who have smoked just once, several years previously, as potentially vulnerable to later smoking uptake.
authors.affiliation: Cancer Research UK Health Behaviour Unit, Department of Epidemiology and Public Health, University College London, London, UK. j.fidler@ucl.ac.uk
authors.forename: J A
authors.initials: JA
authors.lastname: Fidler
authors.forename: J
authors.initials: J
authors.lastname: Wardle
authors.forename: N Henning
authors.initials: NH
authors.lastname: Brodersen
authors.forename: M J
authors.initials: MJ
authors.lastname: Jarvis
authors.forename: R
authors.initials: R
authors.lastname: West
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D002648:Child; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D010290:Parents / Q000523:psychology; D018570:Risk Assessment / Q000379:methods; D012907:Smoking / Q000523:psychology*; D016540:Smoking Cessation / Q000523:psychology*; D013997:Time Factors