title: Condom use as a function of time in new and established adolescent sexual relationships.
abstract: OBJECTIVE
  This study sought to describe condom use over time in new and established adolescent relationships.
  
  
  METHODS
  The outcome variable was time (in days) until first unprotected coital event. Analyses involved comparisons of Kaplan-Meier survival curves and Cox proportional hazards models.
  
  
  RESULTS
  Survival functions for the 2 relationship groups were significantly different. However, by 21 days the curves had converged: 43% of new and 41% of established relationships involved no unprotected coital events. Time to first unprotected coital event was significantly longer in new than in established relationships.
  
  
  CONCLUSIONS
  Prolongation of condom use in ongoing relationships may be a useful intervention to prevent sexually transmitted diseases.
authors.affiliation: Section of Adolescent Medicine, Division of Biostatistics, and the Regenstrief Institute for Health Care, Indiana University School of Medicine, Indianapolis, USA. jfortenb@iupui.edu
authors.forename: J Dennis
authors.initials: JD
authors.lastname: Fortenberry
authors.forename: Wanzhu
authors.initials: W
authors.lastname: Tu
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Harezlak
authors.forename: Barry P
authors.initials: BP
authors.lastname: Katz
authors.forename: Donald P
authors.initials: DP
authors.lastname: Orr
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior; D000328:Adult; D017280:Condoms / Q000706:statistics & numerical data*; D003268:Contraception Behavior; D005260:Female; D006801:Humans; D007196:Indiana; D008297:Male; D016016:Proportional Hazards Models; D021841:Safe Sex; D012749:Sexually Transmitted Diseases / Q000517:prevention & control*; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D013997:Time Factors