Chlamydia trachomatis infection as a risk factor for invasive cervical cancer

Cervical carcinoma is a sexually transmitted disease most strongly linked w ith human-papillomavirus (HPV) infection. We conducted a prospective sero-e pidemiologic study to evaluate the role of Chlamydia trachomatis infection in the development of cervical carcinoma, with invasive cancer as an end po int. A nested case-control study within a cohort of 530000 Nordic women was performed. Linking data files of 3 Nordic serum banks and the cancer regis tries of Finland, Norway and Sweden identified 182 women with invasive cerv ical carcinoma diagnosed during a mean follow-up of 5 years after serum sam pling. The serum samples of the cases and matched cancer-free controls were analyzed for IgG antibodies to C. trachomatis, C. pneumoniae (a control mi crobe) and HPV types 16, 18 and 33, as well as for serum cotinine (an indic ator of tobacco smoking). Serum antibodies to C. trachomatis were associate d with an increased risk for cervical squamous-cell carcinoma (HPV- and smo king-adjusted OR, 2.2; 95% CI, 1.3-3.5). The association remained also afte r adjustment for smoking both in HPV16-seronegative and -seropositive cases (OR, 3.0; 95% Cl, 1.8-5.1; OR, 2.3, 95% CI, 0.8-7.0 respectively). No such association was found for C. pneumoniae. Our prospective study provides se roepidemiologic evidence that infection with C. trachomatis confers an incr eased risk for subsequent development of invasive squamous-cell carcinoma o f the uterine cervix. (C) 2000 Wiley-Liss, Inc.