title: Urine-based testing for Chlamydia trachomatis among young adults in a population-based survey in Croatia: feasibility and prevalence.
abstract: BACKGROUND
  We assessed the feasibility of collecting urine samples for testing on genital Chlamydia trachomatis infection in a population-based survey, and prevalence of this infection among young people aged 18-25 in Croatia. In Croatia, as in the other countries of Eastern Europe, there is a lack of data on prevalence of C. trachomatis in the general population, including young adults.
  
  
  METHODS
  We sampled participants using a nationally representative, multi-stage stratified probability sample of young men and women. Detection of C. trachomatis DNA in urine samples was performed by using a real-time PCR assay COBAS® TaqMan® CT Test, v2.0.
  
  
  RESULTS
  Overall, 1005 young adults participated in the behavioural part of the survey, and 27.9% men and 37.5% women who were sexually experienced agreed to provide urine samples for testing on C. trachomatis. Using multivariate analysis, women were significantly more likely to provide urine samples than men (aOR = 1.53, 95% CI 1.14-2.06) as were those who reported no condom use at last intercourse (aOR = 1.95, 95% CI 1.44-2.62). Prevalence of C. trachomatis infection among those who were sexually experienced was 7.3% in men and 5.3% in women.
  
  
  CONCLUSIONS
  Population-based surveys that use probabilistic sampling are a feasible way to obtain population estimates of C. trachomatis prevalence among young adults in Croatia, but it is challenging to obtain an adequate response rate. The prevalence of C. trachomatis among young adults in Croatia found in this study was higher than that found in other European countries with similar survey response rates.
authors.affiliation: WHO Collaborating Centre for Capacity Development in HIV Surveillance; School of Medicine, Zagreb, Croatia. Ivana.Bozicevic@lshtm.ac.uk
authors.forename: Ivana
authors.initials: I
authors.lastname: Božičević
authors.forename: Ivana
authors.initials: I
authors.lastname: Grgić
authors.forename: Snježana
authors.initials: S
authors.lastname: Židovec-Lepej
authors.forename: Jurja-Ivana
authors.initials: JI
authors.lastname: Čakalo
authors.forename: Sanja
authors.initials: S
authors.lastname: Belak-Kovačević
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Štulhofer
authors.forename: Josip
authors.initials: J
authors.lastname: Begovac
mesh_terms: D000293:Adolescent; D000328:Adult; D002690:Chlamydia Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000652:urine; D002692:Chlamydia trachomatis / Q000235:genetics / Q000302:isolation & purification*; D017523:Croatia / Q000453:epidemiology; D003430:Cross-Sectional Studies; D004269:DNA, Bacterial / Q000652:urine*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D015995:Prevalence; D012725:Sexual Behavior; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial