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O04.4 The netherlands chlamydia cohort study (NECCST): risks of long-term complications following chlamydia trachomatis infections in women
  1. Hoenderboom Bm1,
  2. Van Benthem Bhb1,
  3. Van Oeffelen Aam1,
  4. Van Bergen Jeam2,
  5. Morré Sa3,
  6. Van Den Broek Ivf1,
  7. Neccst Study Group4
  1. 1National institute for Public Health and the Environment, Bilthoven, the Netherlands
  2. 2Department of General Practice, Academic Medical Centre and Sti Aids The Netherlands, Amsterdam, the Netherlands
  3. 3Laboratory of Immunogenetics, Vu University Medical Centre, Amsterdam, the Netherlands
  4. 4On Behalf of the Neccst Group, Bilthoven, the Netherlands


Introduction The Netherlands Chlamydia Cohort Study (NECCST) follows a cohort of women of reproductive age for ≥10 years to investigate Chlamydia trachomatis (CT) related risk (factors) for late complications including the role of host genetic biomarkers. This cohort builds on a prior large-scale Chlamydia Screening Implementation (CSI, 2008–2011). Here outcomes from the first NECCST collection round are described.

Methods In 2015–16 CSI women were invited to participate in NECCST. Data on CT-infections, pregnancies and the late complications Pelvic Inflammatory Disease (PID), ectopic pregnancy (EP) and tubal infertility (TI) were collected by questionnaires. CT Immunoglobulin G (IgG) was measured in self-collected blood samples. A positive CT history was defined as ≥1 positive outcome, either a positive CSI CT Polymerase Chain Reaction (PCR) result, a self-reported CT-infection or CT IgG presence. Risks were compared between women with/without a positive CT-history in NECCST-data combined with CSI-data.

Results Among the 5704 women enrolled, CT IgG prevalence was 14.5%. Of women with self-reported CT-infection or who had been CSI-PCR positive, 38.1% was CT-IgG positive. Of women without a self-reported CT-infection and who had been CSI-PCR negative, 7.0% was CT-IgG positive. Overall 29.2% (n=1,665) had a positive CT-history. Women with a positive CT-history reported less planned pregnancies compared to women with a negative CT-history (19.5% vs 27.4%, p<0.001). In contrast, unplanned pregnancies were more common among women with a positive CT-history (24.7% vs. 12.4%, p<0.001). Women with a positive CT-history had a significantly higher risk of PID and TI compared to women with a negative CT-history: 5.0% vs. 2.0% (p<0.001) and 1.1% vs. 0.3% (p<0.001), respectively.

Conclusion Intermediate outcomes of NECCST after 4–7 years follow-up from CSI suggest a higher risk for PID and TI in women with a positive CT-history. NECCST is expected to yield valuable results for identification of risk factors for CT-complications which might enable targeted preventive methods.

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