RT Journal Article SR Electronic T1 Condom effectiveness for prevention of Chlamydia trachomatis infection JF Sexually Transmitted Infections JO Sex Transm Infect FD BMJ Publishing Group Ltd SP 323 OP 325 DO 10.1136/sti.2004.012799 VO 81 IS 4 A1 L M Niccolai A1 A Rowhani-Rahbar A1 H Jenkins A1 S Green A1 D W Dunne YR 2005 UL http://sti.bmj.com/content/81/4/323.abstract AB Background/objectives: A growing body of evidence is increasingly demonstrating the effectiveness of condoms for sexually transmitted infection (STI) prevention. The purpose of the present analysis was to provide a disease specific estimate for the effectiveness of condoms in preventing Chlamydia trachomatis infection while controlling for known exposure to infection. Methods: Condom effectiveness for C trachomatis was estimated using a medical record database from a public sexually transmitted disease clinic (n = 1455). Clients were classified as having known exposure to C trachomatis if they presented to the clinic as a contact to an infected partner. Results: Among clients with known exposure, 13.3% of consistent condom users were diagnosed with C trachomatis infection compared to 34.4% of inconsistent condom users (adjusted odds ratio = 0.10; 95% CI: 0.01 to 0.83). Among clients with unknown exposure, there was no observed protective effect of condoms. Conclusions: This study provides further evidence that condoms are effective in preventing C trachomatis infection by reporting a disease specific estimate and restricting analyses to individuals with known exposure.