RT Journal Article SR Electronic T1 Chlamydia trachomatis and risk of cervical intraepithelial neoplasia grade 3 or worse in women with persistent human papillomavirus infection: a cohort study JF Sexually Transmitted Infections JO Sex Transm Infect FD BMJ Publishing Group Ltd SP 550 OP 555 DO 10.1136/sextrans-2013-051431 VO 90 IS 7 A1 Jensen, Kirsten E A1 Thomsen, Louise T A1 Schmiedel, Sven A1 Frederiksen, Kirsten A1 Norrild, Bodil A1 van den Brule, Adriaan A1 Iftner, Thomas A1 Kjær, Susanne K YR 2014 UL http://sti.bmj.com/content/90/7/550.abstract AB Objectives Some studies suggest that Chlamydia trachomatis (CT) enhances cervical carcinogenesis; however, a possible confounding effect of persistent human papillomavirus (HPV) infection was not addressed. We examined the potential role of CT infection in the development of subsequent cervical intraepithelial neoplasia grade 3 or worse (CIN3+) in women with prevalent HPV infection and in a subgroup of women with persistent HPV infection. Methods Participants in this population-based cohort study underwent a structured interview, including history of CT infection, and subsequently cervical exfoliated cells were obtained for HPV DNA and CT DNA testing. Women with high-risk HPV DNA infection and no prevalent cervical disease constituted the overall study population (n=1390). A subgroup of women with persistent HPV infection (n=320) was also identified. All women were passively followed for development of cervical lesions in the national Pathology Data Bank. HRs and 95% CIs for CIN3+ during follow-up (up to 19 years) were estimated in an accelerated failure time model. Results Women who reported more than one CT infection had a statistically significantly increased risk of CIN3+ (high-risk HPV-positive, HR=2.51, 95% CI 1.44 to 4.37) (persistent HPV infection, HR=3.65, 95% CI 1.53 to 8.70). We found no association between CT DNA and subsequent risk of CIN3+ among women who were HPV-positive or had a persistent HPV infection at baseline. Conclusions Repeated CT infections increased the risk of CIN3+ among women with prevalent as well as persistent high-risk HPV infection.