title: Sex partner concurrency: measurement, prevalence, and correlates among urban 18-39-year-olds.
abstract: BACKGROUND
  Sex partner concurrency probably accelerates the spread of sexually transmitted disease (STD) and HIV, yet few data exist on population prevalence or correlates.
  
  
  OBJECTIVE
  The goal of the study was to compare definitions and estimate the frequency of concurrent partnerships and to identify individual and partnership correlates of con-currency.
  
  
  METHODS
  A random-digit-dialing survey (n = 637) was performed to collect demographic information, sexual history and history of STD, and partnership characteristics.
  
  
  RESULTS
  Men reported concurrency more frequently than women. For men, lifetime partners (odds ratio [OR], 1.15 per partner; 95% CI, 1.07-1.23), a night in jail (OR, 1.99; 95% CI, 1.03-3.82), and same sex partners (OR, 1.88; 95% CI, 0.92-3.84) were associated with concurrency. Important factors for women were first coitus before age 16 (OR, 2.90; 95% CI, 1.38-6.10), lifetime partners (OR, 1.09 per partner; 95% CI, 1.01-1.16), and STD diagnoses during relationship (OR, 3.53; 95% CI, 1.55-8.05). Partnership characteristics associated with concurrency included lifetime partners (OR, 1.09; 95% CI, 1.05-1.14), race discordance (OR, 1.72; 95% CI, 1.14-2.59), married/living together (OR, 0.60; 95% CI, 0.36-0.98), night in jail (OR, 2.04; 95% CI, 1.32-3.17), partnership duration of >6 months (OR, 2.43; 95% CI, 1.41-4.19), and STD diagnoses during relationship (OR, 2.68; 95% CI, 1.42-5.07).
  
  
  CONCLUSIONS
  Concurrency was independently associated with individual STD risk. Sex differences may reflect true behavioral differences or differential reporting.
authors.affiliation: University of Washington, Seattle, Washington, USA.
authors.forename: Lisa E
authors.initials: LE
authors.lastname: Manhart
authors.forename: Sevgi O
authors.initials: SO
authors.lastname: Aral
authors.forename: King K
authors.initials: KK
authors.lastname: Holmes
authors.forename: Betsy
authors.initials: B
authors.lastname: Foxman
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D012307:Risk Factors; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D012747:Sexual Partners; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D014505:Urban Population / Q000706:statistics & numerical data*