Bonnie Darves

August 07, 2007

August 7, 2007 (Seattle) — Male circumcision (MC) has been found to reduce risk of HIV acquisition for the men themselves, and the emerging body of evidence — 3 recent randomized controlled trials and scores of observational studies — supporting this has spawned strong interest in employing the surgical procedure as a preventive measure. Little has been known, however, about whether MC reduces the risk of non-HIV sexually transmitted infections (STIs) in women. A new study, presented here at the 17th Meeting of the International Society for Sexually Transmitted Diseases Research, suggests that the protective effect of MC may not transfer to STI risk reduction in female sexual partners.

The multicenter study, analyzing data from a prospective cohort study (the HC-HIV Study) of 5925 African and Thai women on the association between hormonal contraception and HIV or STI, found that MC did not significantly reduce women's risk of acquiring gonococcal, trichomonal, or chlamydial infections.

"There was little difference [in STI incidence] between the women with circumcised partners and those with uncircumcised partners — so we concluded that there really was no effect of circumcision in this population," said study coauthor William C. Miller, MD, PhD, MPH, associate professor of medicine at the University of North Carolina at Chapel Hill. He noted that there also is no conclusive evidence that MC is protective against men's acquisition of the 3 STIs studied, despite the fact that male foreskin is known to be a "hospitable" environment for pathogen growth.

The study was conducted in a population of women who were primarily at low risk for an STI (mean age, 25 years). The participants underwent clinical examination and specimen collection at baseline and every 3 months for a period of 15 to 24 months. Overall, 52% of participants reported having a circumcised partner, and 87% cohabited with their partner. Only 9 of the women were found to have an STI at enrollment.

At endpoint, the incidence of chlamydia per 100 person years (PY) was 4.5 in women with circumcised partners compared with 3.9 per 100 PY in the women with uncircumcised partners. Respective results for gonococcal infection were 3.7 and 3.1 and were 4.7 and 3.9 for trichomonas. In multivariate analysis, after controlling for contraceptive method, age, coital debut age, and country, the adjusted hazard ratio (HR), comparing women with circumcised partners with those with uncircumcised partners, was 1.22 for chlamydia and 0.93 for gonococcal infection. Interestingly, in analyses of the women who reported having only 1 sexual partner, women with circumcised partners appeared to have slightly higher risk of chlamydia (1.01 vs 1.75; HR, 1.33) than those with uncircumcised partners.

Overall, the findings did not surprise King Holmes, MD, PhD, director of the Center for AIDS and Sexually Transmitted Diseases at the University of Washington in Seattle, but they did, he suggested, indicate the need for longer-term study. "The study is interesting, but one point to make is that chlamydia and gonorrhea involve the urethra and not the penile epithelium, so they're not the prime suspects for diseases that are affected by male circumcision," he said, unlike diseases such as chancroid, herpes, and syphilis. "The question that remains, I think, is whether male circumcision will be associated with increased risk of bacterial vaginosis — some data have suggested that women with uncircumcised partners have an increased risk."

Dr. Miller acknowledged the study's limitations, particularly its reliance on both secondary data and self-reported sexual and behavioral data. He also noted that although MC interventions are being planned worldwide to stem transmission of HIV, "the effect of [male] circumcision on women's STI risk is not yet known."

Dr. Miller and Dr. Holmes report no relevant financial relationships.

17th Meeting of the International Society for Sexually Transmitted Diseases Research: Abstract 449. Presented July 30, 2007.


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