title: Time-varying effects of smoking quantity and nicotine dependence on adolescent smoking regularity.
abstract: BACKGROUND
  Little is known about time-varying effects of smoking quantity and nicotine dependence on the regularity of adolescent smoking behavior.
  
  
  METHODS
  The sample was drawn from the Social and Emotional Contexts of Adolescent Smoking Patterns Study which followed adolescent smokers over 5 assessment waves spanning 48 months. Participants included former experimenters (smoked <100 cigarettes/lifetime but did not smoke in past 90 days), recent experimenters (smoked <100 cigarettes/lifetime and smoked in past 90 days), and current smokers (smoked >100 cigarettes/lifetime and smoked in past 30 days). Mixed-effects regression models were run to examine the time-varying effects of smoking quantity and nicotine dependence on regularity of smoking behavior, as measured by number of days smoked.
  
  
  RESULTS
  Smoking quantity and nicotine dependence were each found to be significantly associated with regularity of adolescent smoking and the size of each effect exhibited significant variation over time. The effect of smoking quantity decreased across time for each smoking group, while the effect of nicotine dependence increased across time for former and recent experimenters. By the 48-month follow-up, the effects of smoking quantity and nicotine dependence had each stabilized across groups.
  
  
  CONCLUSIONS
  This study reveals that smoking quantity and nicotine dependence are not static risk factors for the development of more regular smoking patterns. At low levels of smoking when nicotine dependence symptoms are less common, smoking quantity is a stronger predictor of increased regularity of smoking, while for more experienced smokers, nicotine dependence predicts further increases in regularity.
authors.affiliation: Psychology Department, Wesleyan University, Middletown, CT 06459, USA. aselya@wesleyan.edu
authors.forename: Arielle S
authors.initials: AS
authors.lastname: Selya
authors.forename: Lisa C
authors.initials: LC
authors.lastname: Dierker
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Rose
authors.forename: Donald
authors.initials: D
authors.lastname: Hedeker
authors.forename: Xianming
authors.initials: X
authors.lastname: Tan
authors.forename: Runze
authors.initials: R
authors.lastname: Li
authors.forename: Robin J
authors.initials: RJ
authors.lastname: Mermelstein
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D005260:Female; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects*; D011795:Surveys and Questionnaires; D013997:Time Factors; D062789:Tobacco Products / Q000009:adverse effects / Q000706:statistics & numerical data*; D014029:Tobacco Use Disorder / Q000209:etiology*; D055815:Young Adult