Table 2

Association between chlamydia positivity and pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility in women participating in NECCST

CasesTimeCrude HRAdjusted HR*†‡
Person-years¶HR95% CIP valueaHR95% CIP value
Pelvic inflammatory disease
 Chlamydia negative10071 02911
 Chlamydia positive5914 3202.601.85 to 3.66<0.00012.221.57 to 3.13<0.0001
Ectopic pregnancy
 Chlamydia negative4171 41211
 Chlamydia positive1114 6840.990.49 to 1.970.800.39 to 1.630.5335
Tubal factor infertility
 Chlamydia negative1571 52311
 Chlamydia positive1814 6994.272.08 to 8.770.00014.222.05 to 8.690.0001
  • Chlamydia positive was defined as a positive PCR-test outcome in the CSI study (CSI-PCR), and/or the presence of chlamydia IgG and/or a self-reported chlamydia infection. For these analyses, multiple imputations were used to estimate time of first chlamydia infection in women without a known first year of chlamydia infection.

  • *PID model adjusted for age (time-varying) and educational level.

  • †Ectopic pregnancy model adjusted for age (time-varying), educational level, number of lifetime partners and migration background.

  • ‡Tubal factor infertility model adjusted for age (time-varying).

  • §Median cases of 15 multiple imputation datasets.

  • ¶Estimated from 15 multiple imputation datasets.

  • aHR, adjusted HR; CSI, Chlamydia Screening Implementation; NECCST, Netherlands Chlamydia Cohort Study.