Serotypes of Chlamydia trachomatis and risk for development of cervical squamous cell carcinoma

Context Human papillomavirus (HPV) infection has been established as a caus e of cervical cancer. Epidemiologic studies suggest that Chlamydia trachoma tis infection. also confers increased risk for cervical squamous cell carci noma (SCC). Whether this risk is serotype-specific is unknown. Objective To study the association between exposure to different C trachoma tis serotypes and subsequent development of cervical SCC. Design and Setting Longitudinal, nested case-control study within a cohort of 530000 women who provided samples to serum banks in Finland, Norway, and Sweden, The data files were linked to respective national cancer registrie s. Subjects One hundred twenty-eight women who had developed invasive cervical SCC at least 12 months following serum donation. Each case had 3 matched c ontrols. Main Outcome Measure Risk for the development of cervical SCC by Ige antibo dies to 10 different C trachomatis serotypes, adjusted for antibodies to HP V types 16, 18, and 33 and for serum cotinine levels. Results Of specific C trachomatis serotypes, serotype CI was most strongly associated with SCC (adjusted odds ratio [OR], 6.6; 95 % confidence interva l [CI], 1.6-27.0), Other serotypes associated with SCC were I (OR, 3.8; 95% CI, 1.3-11.0) and D (OR, 2.7; 95% CI, 1.3-5.6). Presence of serum IgG anti bodies to more than 1 serotype increased the adjusted ORs for SCC (P<.001 f or trend). Conclusions Chlamydia trachomatis serotype C is most strongly associated wi th subsequent development of cervical SCC. Increasing numbers of exposures to different C trachomatis serotypes also increases risk, Our results stren gthen the evidence that there is a link between past C trachomatis infectio n and cervical SCC.