title: Incidence of pelvic inflammatory disease in a large cohort of women tested for Chlamydia trachomatis: a historical follow-up study.
abstract: BACKGROUND
  Chlamydia trachomatis is a highly prevalent sexually transmitted disease. Testing rates among young Norwegian women are high. Young women diagnosed with C. trachomatis are often worried about future complications.
  
  
  METHODS
  Our cohort consisted of 24,947 women born 1970-1984 who were tested for C. trachomatis infection during 1990-2005. We linked C. trachomatis laboratory data to data on hospitalizations for pelvic inflammatory disease during 1990-2005. Cox regression analysis with time-dependent covariates adjusted for age at first test was used to assess the association between C. trachomatis history and pelvic inflammatory disease.
  
  
  RESULTS
  Follow-up until the end of 2005 included 201,387 woman-years. The incidence rate of hospitalization for pelvic inflammatory disease was higher among women with prior C. trachomatis infection than among women with negative tests only (48 events during 32,057 person-years and 143 events during 169,192 person-years, corresponding to 0.15 and 0.08 per 100 person-years, respectively). The corresponding hazard ratio adjusted for age at first test was 1.69 (95% CI, 1.21-2.36).
  
  
  CONCLUSIONS
  Our data show a link between a diagnosis of C. trachomatis infection and subsequent pelvic inflammatory disease. However, pelvic inflammatory disease was a rare event irrespective of C. trachomatis status. These, together with other recent findings, can be used to reassure women worried about their future reproductive health following a diagnosis of C. trachomatis.
authors.affiliation: Department of Preventive Health Care, SINTEF Technology and Society, Trondheim, Norway. inger.j.bakken@ntnu.no
authors.forename: Inger J
authors.initials: IJ
authors.lastname: Bakken
authors.forename: Sara
authors.initials: S
authors.lastname: Ghaderi
mesh_terms: D002690:Chlamydia Infections / Q000150:complications / Q000453:epidemiology*; D002692:Chlamydia trachomatis; D005260:Female; D005500:Follow-Up Studies; D006760:Hospitalization; D006801:Humans; D015994:Incidence; D009664:Norway; D000292:Pelvic Inflammatory Disease / Q000150:complications / Q000453:epidemiology*; D016016:Proportional Hazards Models; D012307:Risk Factors
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