Background Chlamydia and gonorrhoea are the most common bacterial sexually transmitted infections (STIs) in Canada. However, the prevalence of these STIs, as well as the risk profile of clients attending public health sexual health (SH) clinics, have not been well characterised in Canada.

Methods Female clients of Hamilton Public Health SH clinics between Jan 2009 and Dec 2011 were enrolled in the study. Retrospective chart review was conducted. Logistic regression was conducted to identify important risk factors for STIs in predicting gonococcal and chlamydial infections.

Results 2694 charts were abstracted from Hamilton Public Health SH clinics. The mean age of the clients was 24 years; 50% of the clients were under 21 years of age. The majority of the clients were sexually active (98%), of whom 147(6%) had both male and female partners, 27(1%) had only female partners, and 2405 (92%) had only male partners. Most clients practised vaginal (96.6%) and oral sex (74%). Anal sex, oral-anal sex and shared sex toys were less common with 12%, 2.2% and 2% of clients reporting these practises, respectively. Over half of the clients reported having more than 1 partner in the past year, 36% of clients reported two or three partners and 15% reported having four or more partners in the past year. The proportion of clients who had at least one test for gonorrhoea and chlamydia during the study period was 58%. The overall prevalence of chlamydia and gonorrhoea were 8% and 1%, respectively. The strongest predictor of these STIs was young age: ORs were 3.4 and 4.2 for age groups < 20 and 20–24 compared to > 30 years old.

Conclusion The prevalence of chlamydia and gonorrhoea was considerably higher in clients attending SH clinics in Hamilton compared to population and family practise based estimates. Age remains the strongest predictor of these infections.