(New York City) A new analysis of previous research indicates there is a lack of sufficient evidence that circumcision reduces the risk of HIV infection or other sexually transmitted infections among men who have sex with men.

Studies also suggest that male circumcision may protect heterosexual men against other sexually transmitted infections, such as syphilis or chlamydial infection. But less is known about whether circumcision provides protection against HIV infection among men who have sex with men (MSM).

In an analysis of 15 studies, Gregorio A. Millett of the Centers for Disease Control and Prevention found that the odds of being HIV-positive were nonsignificantly lower among MSM who were circumcised than uncircumcised.

Their results are published in the current edition of the Journal of the American Medical Association.

The studies included a total of 53,567 MSM participants - 52 percent of whom were circumcised.

Millett and his associates found that there was a statistically significant protective association of circumcision with HIV infection was found for MSM studies conducted prior to the introduction of highly active antiretroviral therapy - known as HAART - in 1996. Of studies conducted after HAART, the association of circumcision and HIV infection was not statistically significant.

“Taken together, these findings indicate insufficient evidence among available observational studies conducted with MSM of an association between circumcision and HIV infection or other STIs,” the researchers write in the JAMA report.

“Additional studies are necessary to elucidate further the relationship between circumcision status and HIV infection or STIs among MSM.”

In an accompanying editorial in the Journal, Drs. Sten H. Vermund and Han-Zhu Qian of the Vanderbilt University School of Medicine say that only future research can answer whether MSM should be circumcised to reduce their HIV risk.

“The meta-analysis by Millett, et. al. is likely to be used by both advocates and detractors of clinical trial investment; some will argue the benefit is likely to be too modest to justify a multimillion dollar clinical trial while others will argue that only a clinical trial will answer this important HIV prevention question,” they said.

“Barriers to circumcision among heterosexual men include human rights issues, ethical and legal issues, high cost, fear of pain, safety concerns, availability of surgery services, and sexual risk compensation if men overrate their degree of protection and ongoing risk. As in other HIV prevention trials, circumcision would likely be insufficiently efficient to be universally effective in reducing HIV risk, and will have to be combined with other prevention modalities to have a substantial and sustained prevention effect.”