Introduction Chlamydia knowledge and sexual practice data were collected from 16–29 year olds during the ACCEPt baseline chlamydia prevalence survey. We report patient chlamydia knowledge and explore whether knowledge is associated with reported sexual practices.

Methods A consecutive sample of 16–29 year olds was recruited from participating general practice clinics. Participants were tested for chlamydia and completed a demographic, sexual practice and knowledge questionnaire. Chlamydia knowledge was assessed via nine true/false questions. Two markers of sexual risk were assessed: two or more partners in the last 12 months and any concurrent sexual partners in the last 12 months. Logistic regression was used to investigate associations between knowledge items and sexual risk. All analyses were adjusted for participant gender and age.

Results A total of 4261 patients (72% female) participated (response rate 70%). 35% reported two or more partners in the last 12 months and 15% reported concurrency. 49% answered seven or more questions correctly and 16% answered four or fewer questions correctly. Participants were less likely to report concurrent sexual partners if they correctly answered questions about the fact that chlamydia is often asymptomatic (OR = 0.84; 95% CI: 0.73–0.96; p < 0.01), that chlamydia is transmissible via oral sex (OR = 0.88; 95% CI: 0.81–0.95; p < 0.01) and that the Pap smear does not test for chlamydia (OR = 0.89; 95% CI: 0.82–0.97; p < 0.01). Participants were less likely to report two or more partners in the last 12 months if they correctly answered questions about how common chlamydia is (OR = 0.91; 95% CI: 0.84–0.98; p < 0.01), the fact that chlamydia is transmissible via oral sex (OR = 0.91; 95% CI: 0.85–0.96; p < 0.01) and that the Pap smear does not test for chlamydia (OR = 0.93; 95% CI: 0.87–0.98; p < 0.01).

Conclusion Chlamydia knowledge appears to be associated with some reported sexual risk practices. Findings can feed into education and behaviour change strategies aimed to control chlamydia.

Disclosure of interest statement ACCEPt was commissioned and funded by the Australian Government Department of Health and Ageing. Additional funding has been received from the National Health and Medical Research Council, the Victorian Department of Health and NSW Health.