41. CIRCUMCISION AND RISK OF HIV SEROCONVERSION IN THE HIM COHORT OF HOMOSEXUAL MEN IN SYDNEY

Abstract

Objectives: We examined circumcision as a risk factor for HIV seroconversion in a community-based cohort of homosexual men in Sydney.

Methods: Between 2001 and 2004, 1427 initially HIV-negative men were enrolled. Circumcision status was self-reported at baseline, and self-report was validated by clinical examination during study visits in a sub-sample of approximately 300 participants. All participants were tested annually for HIV and offered testing for other sexually transmitted infections (STIs). Detailed information on sexual risk behaviours was collected every 6 months.

Results: At baseline, 66% of participants reported being circumcised; mostly as infants. The proportion circumcised ranged from 83% in those aged 45 or more to only 50% in those aged less than 25 (p < 0.0001). There were 49 HIV seroconversions through 2006, an incidence of 0.80 per 100 person years (PY). Anorectal gonorrhoea and anal warts were independent risk factors for HIV infection. Overall, being circumcised was not related to HIV infection (relative risk (RR) 1.07, 95% CI 0.56-2.06). After controlling for non-concordant unprotected anal intercourse (UAI), anorectal STIs and age, there remained no association with circumcision (RR = 0.88, 95% CI 0.45-1.74). Only nine of the 49 seroconversions occurred among men who reported no receptive UAI, an incidence of 0.35 per 100PY. In this group, circumcision was also not associated with HIV seroconversion (RR = 0.99, 95% CI 0.25-3.96).

Conclusion: Overall, circumcision status was not associated with HIV seroconversion. In addition, analyses limited to those men who reported no receptive UAI, who are more likely to have been infected through insertive sex, suggest that circumcision may not reduce HIV risk even for insertive anal intercourse. Other preventive strategies are required to reduce HIV incidence in homosexual men.