title: Frequency and risk factors for incident and redetected Chlamydia trachomatis infection in sexually active, young, multi-ethnic women: a community based cohort study.
abstract: OBJECTIVE
  To investigate the frequency and risk factors for incident and redetected Chlamydia trachomatis infection in sexually active, young, multi-ethnic women in the community.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  20 London universities and Further Education colleges.
  
  
  METHODS
  954 sexually experienced women, mean age 21.5 years (range 16-27), 26% from ethnic minorities, who were recruited to the Prevention of Pelvic Infection (POPI) chlamydia screening trial between 2004 and 2006, and returned repeat postal self-taken vaginal swabs 11-32 (median 16) months after recruitment.
  
  
  RESULTS
  The estimated annual incidence of chlamydia infection among 907 women who tested negative at baseline was 3.4 per 100 person-years (95% CI 2.5 to 4.6 per 100 person-years), but 6.6 per 100 person-years (95% CI 4.5 to 9.3 per 100 person-years) in the 326 teenagers (<20 years). Predictors of incident chlamydia infection were age <20 years (relative risk (RR) 4.0, 95% CI 2.1 to 7.5), and (after adjusting for age) a new sexual partner during 12 months follow-up (RR 4.4, 95% CI 2.0 to 9.9), smoking (RR 2.2 95% CI 1.2 to 3.9), concurrent bacterial vaginosis (RR 2.0 95% CI 1.1 to 3.9) and high risk carcinogenic human papillomavirus (RR 2.2, 95% CI 1.1 to 4.3). Of 47 women positive for chlamydia at baseline, 12 (25.5%, 95% CI 13.9% to 40.3%) had redetected infection at a median of 16 months follow-up. Taking into account follow-up time (65 person-years), the annual redetection rate was 18.5 per 100 person-years (95% CI 9.9 to 30.0 per 100 person-years).
  
  
  CONCLUSIONS
  One in four women with chlamydia infection at baseline retested positive, supporting recent recommendations to routinely retest chlamydia positives.
authors.affiliation: Division of Population Health Sciences, St George's, University of London, London, UK HIV & STI Department, Centre for Infectious Disease Surveillance and Control, Public Health England, London, UK.
authors.forename: Adamma
authors.initials: A
authors.lastname: Aghaizu
authors.affiliation: Division of Population Health Sciences, St George's, University of London, London, UK.
authors.forename: Fiona
authors.initials: F
authors.lastname: Reid
authors.affiliation: Barts and the London, School of Medicine and Dentistry, Queen Mary, University of London, London, UK.
authors.forename: Sally
authors.initials: S
authors.lastname: Kerry
authors.affiliation: Department of Genitourinary Medicine, St George's Hospital, London, UK.
authors.forename: Phillip E
authors.initials: PE
authors.lastname: Hay
authors.affiliation: Aintree Hospital, Liverpool, UK.
authors.forename: Harry
authors.initials: H
authors.lastname: Mallinson
authors.affiliation: Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Jorgen S
authors.initials: JS
authors.lastname: Jensen
authors.affiliation: Division of Population Health Sciences, St George's, University of London, London, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Kerry
authors.affiliation: Division of Population Health Sciences, St George's, University of London, London, UK.
authors.forename: Sheila
authors.initials: S
authors.lastname: Kerry
authors.affiliation: Division of Population Health Sciences, St George's, University of London, London, UK.
authors.forename: Pippa
authors.initials: P
authors.lastname: Oakeshott
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002690:Chlamydia Infections / Q000175:diagnosis / Q000453:epidemiology* / Q000208:ethnology; D002692:Chlamydia trachomatis; D015331:Cohort Studies; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008131:London / Q000453:epidemiology; D030361:Papillomavirus Infections / Q000453:epidemiology* / Q000821:virology; D012008:Recurrence; D012307:Risk Factors; D012725:Sexual Behavior / Q000706:statistics & numerical data*; D012747:Sexual Partners; D012907:Smoking / Q000453:epidemiology*; D016585:Vaginosis, Bacterial / Q000453:epidemiology*; D055815:Young Adult
keywords: Chlamydia Infection; Chlamydia Trachomatis; Public Health; Sexual Health; Testing
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