Circumcision protects gay men who have a 'preference' for insertive sex from HIV

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Circumcision may protect gay men who are exclusively insertive for anal sex from infection with HIV, an Australian study published in the November 13th edition of AIDS suggests.

But this finding is based upon just seven infections amongst men who expressed a preference for insertive sex. The investigators found that amongst the men who reported only insertive sex as a behaviour, circumcision did not significantly reduce the risk of infection with HIV.

The study also showed that overall circumcision did not protect gay men from infection with HIV. Earlier data from the study presented to the conference of the International AIDS Society in Sydney in 2007 showed that circumcision had no protective effect.

Glossary

voluntary male medical circumcision (VMMC)

The surgical removal of the foreskin of the penis (the retractable fold of tissue that covers the head of the penis) to reduce the risk of HIV infection in men.

insertive

Insertive anal intercourse refers to the act of penetration during anal intercourse. The insertive partner is the ‘top’. 

circumcision

The surgical removal of the foreskin of the penis (the retractable fold of tissue that covers the head of the penis) to reduce the risk of HIV infection in men.

person years

In a study “100 person years of follow-up” could mean that information was collected on 100 people for one year, or on 50 people for two years each, or on ten people over ten years. In practice, each person’s duration of follow-up is likely to be different.

receptive

Receptive anal intercourse refers to the act of being penetrated during anal intercourse. The receptive partner is the ‘bottom’.

Gay and other men who have sex with men continue to be one of the groups most affected by HIV. Consequently, there is a need for new approaches to HIV prevention in this population.

Studies in Africa have shown that circumcision reduces the risk of HIV infection for heterosexual men. However, a recent meta-analysis found no conclusive evidence that circumcision was protective for gay men.

Researchers from the Health in Men (HIM) study therefore investigated the relationship between circumcision and the risk of HIV infection in a population of 1426 HIV-negative gay men in Sydney. In total, 938 of these men were circumcised

The men were recruited between 2001 and 2004 and followed until the end of 2007. On entry to the study, the men reported their circumcision status and this was confirmed by clinical examination.

Every six months the men attended for a follow-up visit when they were tested for HIV and the men were asked if they had had unprotected anal intercourse. In addition, individuals were also asked to say if they were insertive or receptive, and if they had a strong preference for adopting the insertive position.

A total of 5161 person years of follow-up were available for analysis, and the median duration of follow-up for each man was 3.9 years.

There were 53 HIV infections, providing an overall incidence of 0.78 per 100 person years.

Statistical analysis that included the entire study population showed that circumcision did not provide any significant protection against infection with HIV.

Only 10% of the study’s person years of follow-up was contributed by men who reported insertive unprotected sex but not receptive sex without a condom. There were only four HIV infections in these men. Analysis showed that circumcised men who only reported insertive unprotected sex did not have a significantly reduced risk of HIV.

Next the investigators restricted their analysis to men who stated a preference for the insertive position in all anal intercourse. These 435 men (279 of whom were circumcised) contributed 1710 person years of follow-up.

There were a total of seven HIV infections in these men, five of which were in the uncircumcised men.

Statistical analysis showed that circumcision was associated with a significant reduction in the risk of HIV infection for men with a preference for insertive anal sex (p = 0.049). This association was strengthened when the investigators adjusted for age and potentially serodiscordant unprotected anal intercourse.

However, three of the men with a preference for insertive sex reported unprotected receptive anal intercourse. But the study's lead author, Dr David Templeton, told aidsmap.com that men expressing a preference for insertive sex adopted this position in almost 99% of instances of anal intercourse.

It is of note, however, that the investigators do not comment on the possibility of study participants providing inaccurate information about their sexual preferences or behaviour to the investigators. It is of note that for reasons of social desirability receptive anal sex is consistently under reported by gay men.

Nevertheless, the investigators comment: “Being circumcised was associated with a significant reduction in HIV incidence among the one-third of participants who reported a preference for the insertive role in anal intercourse”.

A total of 9% of HIV infections in the cohort could, the investigators conclude be attributed to being uncircumcised. “Among participants who preferred the insertive role in anal intercourse, the estimate proportion of HIV infections that could be attributed to being uncircumcised by 75.7%.”

They do however acknowledge that “the key limitation of our analysis was lack of power due to relatively small numbers of HIV infections in the HIM cohort and the low incidence of HIV infection among predominately insertive men.”

The investigators call for randomised controlled trials to further explore the relationship between circumcision and the risk of HIV for gay men.

Such studies could, however, be difficult to design and the investigators question if they would be worthwhile. They note that the studies “would require high HIV incidence, low baseline circumcision prevalence and large numbers of participants exclusively or predominately practicing the insertive role.” The investigators emphasise that “such attributes are necessary for sufficient study power to detect an association between circumcision status with the relatively infrequent outcome measure of HIV acquisition via insertive anal intercourse.”

References

Templeton DJ et al. Circumcision and risk of HIV infection in Australian homosexual men. AIDS 23: 2347-51, 2009.