Circumcision and risk of HIV infection in Australian homosexual men.

Circumcision and risk of HIV infection in Australian homosexual men.

The aim of the study was to assess circumcision status as a risk factor for HIV seroconversion in homosexual men. The Health in Men (HIM) study was a prospective cohort of homosexual men in Sydney, Australia. HIV-negative men (n = 1426) were recruited primarily from community-based sources between 2001 and 2004 and followed to mid-2007. Participants underwent annual HIV testing, and detailed information on sexual risk behaviour was collected every 6 months. The main outcome measure was HIV incidence in circumcised compared with uncircumcised participants, stratified by whether or not men predominantly practised the insertive role in anal intercourse. There were 53 HIV seroconversions during follow-up; an incidence of 0.78 per 100 person-years. On multivariate analysis controlling for behavioural risk factors, being circumcised was associated with a nonsignificant reduction in risk of HIV seroconversion [hazard ratio 0.78, 95% confidence interval (CI) 0.42-1.45, P = 0.424]. Among one-third of study participants who reported a preference for the insertive role in anal intercourse, being circumcised was associated with a significant reduction in HIV incidence after controlling for age and unprotected anal intercourse (UAI) (hazard ratio 0.11, 95% CI 0.03-0.80, P = 0.041). Those who reported a preference for the insertive role overwhelmingly practised insertive rather than receptive UAI. Overall, circumcision did not significantly reduce the risk of HIV infection in the Health in Men cohort. However, it was associated with a significant reduction in HIV incidence among those participants who reported a preference for the insertive role in anal intercourse. Circumcision may have a role as an HIV prevention intervention in this subset of homosexual men.

Editors’ note: With strategic positioning among gay men on the rise in Australia and the USA (HIV-negative men adopting the insertive role in unprotected anal sex to reduce their risk with HIV-positive partners or those of unknown status), there is increasing interest in the possible protection that male circumcision may provide to primarily insertive men who have sex with men. This first prospective study, following on mixed findings from cross-sectional studies, included systematic validation of circumcision status in a sub-group of participants to assess validity of self-report. Despite lowered study power (only 33% of person-years of exposure were in men with a preference for the insertive role), circumcised men with this preference had significantly reduced HIV incidence. Only randomised controlled trials recruiting uncircumcised men who have sex with men and who predominantly or exclusively practise insertive anal sex in high HIV incidence settings will answer once and for all the question of whether male circumcision reduces the risk of HIV acquisition for primarily insertive men who have sex with men as it does for men who have sex with women