In a new analysis of previous research, investigators from the US Centers for Disease Control and Prevention (CDC) said they found insufficient evidence that circumcision reduced the risk of HIV and other sexually transmitted infections among gay and bisexual men (men who have sex with men).

The study is published in the October 8 issue of the Journal of the American Medical Association, JAMA.

Studies show that male circumcision reduces female to male transmission of HIV by 50 to 60 per cent, and may also protect heterosexual men from other sexually transmitted infections (STI) such as syphilis and chlamydia, but the extent to which men who have sex with men are protected is not well known wrote Dr Gregorio A. Millett and colleagues of the CDC in Atlanta, Georgia.

Millett and colleagues conducted a meta-analysis that pooled data from 15 studies covering more than 53,500 men (at least half of whom were circumcised) to see if there were any strong links between circumcision and infections of HIV and other sexually transmitted diseases among men who have sex with men.

The results showed that compared to the uncircumcised, the odds of being HIV-positive were lower among the circumcised men who had sex with men but this was not statistically significant and therefore unereliable.

However, when the researchers looked more closely, they found that the link between HIV infection and circumcision was statistically significant for studies that took place before highly active antiretroviral therapy (HAART) started in 1996. And studies that took place after that, did not show statistically significant links.

Interpreting the results, the authors suggested there could be a number of reasons. One possible explanation for the differences between the pre- and post- HAART results could be that men who had sex with men took more risks after HAART came in.

“It has been well documented that beliefs that HAART limits HIV transmissibility are associated with increases in sexual risk behavior among MSM [men who have sex with men], and that the era since the advent of HAART has been defined by higher rates of sexual risk behaviors among MSM, outbreaks of STIs, and increasing rates of HIV infection,” wrote Millett and colleagues, who concluded that:

“Pooled analyses of available observational studies of MSM revealed insufficient evidence that male circumcision protects against HIV infection or other STIs.”

However, they said more research on male circumcision for HIV prevention was needed:

“The comparable protective effect of male circumcision in MSM studies conducted before the era of highly active antiretroviral therapy, as in the recent male circumcision trials of heterosexual African men, supports further investigation.”

Drs Stern Vermund and an-Zhu Qian of Vanderbilt University School of Medicine in Nashville, Tennessee, wrote in an accompanying editorial that only new research could answer the question of whether men who have sex with men should be circumcised to reduce their risk of HIV infection.

Their view was that this CDC study will be used by those for and against investing in clinical trials, the former to argue that the benefit is likely to be too small to justify the millions of dollars a trial would cost, and the latter to argue that only a clincial trial can answer the question.

“Circumcision Status and Risk of HIV and Sexually Transmitted Infections Among Men Who Have Sex With Men: A Meta-analysis.”
Gregorio A. Millett; Stephen A. Flores; Gary Marks; J. Bailey Reed; Jeffrey H. Herbst
JAMA. 2008;300(14):1674-1684.
Vol. 300 No. 14, October 8, 2008

Click here for Abstract.

“Circumcision and HIV Prevention Among Men Who Have Sex With Men: No Final Word.
Vermund and Qian.
JAMA.2008; 300: 1698-1700
Vol. 300 No. 14, October 8, 2008

Click here for full article (subscription required).

Source: Journal abstract, JAMA.

Written by: Catharine Paddock, PhD.