title: Do people really know their sex partners? Concurrency, knowledge of partner behavior, and sexually transmitted infections within partnerships.
abstract: OBJECTIVE
  An individual's risk of sexually transmitted infections (STIs) has been associated empirically with the individual having concurrent sexual partners (individual's concurrency) and, theoretically, with the individual's partner having concurrent partners (partner's concurrency).
  
  
  OBJECTIVE
  The goals of this study were to assess the relationship of STI to individual's concurrency, the partner's concurrency, and awareness of the partner's concurrency.
  
  
  METHODS
  We recruited 192 individuals aged 18 to 30 from sexually transmitted disease and family planning clinics in 96 partner dyads that reported first sexual contact during the previous 3 months. All individuals underwent computer interviews and testing for Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis. Individuals' self-reports of concurrency and perceptions of partners' concurrency were compared within dyads by kappa statistic; associations of STI with individual's concurrency, partner's concurrency, and knowledge of partner's concurrency were examined using chi-squared analysis, t tests, and multivariate logistic regression.
  
  
  RESULTS
  Only 26% of individuals whose partners had other partners were aware of this (kappa = 0.17 for agreement of perceptions vs. partners' reports of concurrency). In multivariate models, STI in individuals was independently associated with partners' concurrency (odds ratio [OR], 3.6), lack of awareness of partner's concurrency (OR, 4.5), perceiving a partner to have concurrent partners when the partner did not (OR, 4.7), living in south San Diego, and sexual contact within 1 week of acquaintance, but not with individuals' concurrency.
  
  
  CONCLUSIONS
  This study demonstrates that STI is associated with partner's concurrency and with not knowing one's partner's behavior.
authors.affiliation: University of California, San Diego, California, USA.
authors.forename: Lydia N
authors.initials: LN
authors.lastname: Drumright
authors.forename: Pamina M
authors.initials: PM
authors.lastname: Gorbach
authors.forename: King K
authors.initials: KK
authors.lastname: Holmes
mesh_terms: D000293:Adolescent; D000328:Adult; D002140:California / Q000453:epidemiology; D005260:Female; D007722:Health Knowledge, Attitudes, Practice; D006801:Humans; D012725:Sexual Behavior; D012747:Sexual Partners; D012749:Sexually Transmitted Diseases / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*