Objective: To investigate Chlamydia trachomatis (Ct) epidemiology among 5829 women 18 to 25 years old, in Costa Rica.
Methods: Data are from a community-based human papillomavirus 16/18 vaccine trial. Before randomization, eligible women who reported previous sexual activity were interviewed and tested for Ct DNA by Hybrid Capture 2 and polymerase chain reaction-based genotyping. Multivariate models were developed.
Results: Overall prevalence was 14.2% (95% confidence interval, 13.3–15.1). Among Ct genotypes, serovar E was the most common (4.3%), followed by serovar F (3.0%), serovar D/Da (2.9%), and serovar I/Ia (2.1%).
Ct increased with lifetime sexual partners of the women, and among women with 1 lifetime partner, with sexual partners of the partner. Current intrauterine device users had an increase in Ct detection [odds ratio (OR) 1.6, 1.1–2.5] but hormonal contraceptives or condom users did not. Miscarriages were associated with a reduction in Ct detection (OR 0.7, 0.5–1.0) while current regular smoking increased it (OR 1.7, 1.2–2.5).
Vaginal discharge, reactive changes, ASCUS or LSIL and moderate to severe inflammation in the cytology were significantly more common among Ct positive women (P <0.001). Gonorrhea prevalence was 0.8%, and it was, as other STIs, highly correlated with Ct detection.
Conclusions: This is a high-prevalence population where we confirmed the strong link between Ct and sexual behavior of women and their partners. The establishment of a screening program in the age group included in this study should be considered. More studies are needed in developing countries to further investigate the role of intrauterine devices and the lack of protection by condoms, in addition to the interplay between Ct and other STIs, ectopy, inflammation, and epithelial abnormalities.