Friday, August 24, 2007

Circumcision may cut HIV risk among some groups of US men

Adam Legge, Monday, August 20, 2007

Circumcision could cut the risk of heterosexual HIV transmission in the United States- especially in some groups such as black and Hispanic men, according to a new evidence review.

But any man considering circumcision needs to discuss the possibility - and the risks associated with the procedure - carefully with their doctor.

Researchers at the US Centers for Disease Control and Prevention have analysed three randomised controlled trials of circumcision as a HIV prevention measure in Africa to find out if any recommendations for the US can be made on their basis.

In each trial - carried out in South Africa, Kenya and Uganda - men who had been randomly assigned to be circumcised were significantly less likely to become infected with HIV up to two years after, compared to a group of men who remained uncircumcised. The risk was cut by between 51 and 60%.

But the potential impact of adult male circumcision on HIV transmission rates in the US is hard to predict, say the researchers writing in PLoS Medicine.

This is because there are many differences between the underlying HIV epidemics in Africa and the US, plus differences in the prevalence of male circumcision in Africa and the US, and the considerable gaps in knowledge about the potential impact of circumcision on HIV transmission among men who have sex with men (MSM).

Adult male circumcision will likely have the largest impact in populations where circumcision has been rare, they say.

But circumcision is already very common in the US with hospital discharge data showing that around two thirds of all newborn boys were circumcised in the 1990s. However circumcision rates have traditionally been lower among Hispanic men in the United States, where only 42% of Mexican-American men participating in the Health and Nutrition Examination Surveys from 1999 to 2004 were circumcised, compared with 88% of non- Hispanic white men and 73% of non-Hispanic black men.

Circumcision rates have been declining in some parts of the United States, particularly the western states, in part because of the higher birth rate among the Mexican-American population. But they have been rising over the past few decades in African-American men, who are the highest risk group of heterosexual men in the United States for HIV infection.

However, based on the African data the authors conclude that "it is likely that circumcision will decrease the probability of a man acquiring HIV via penile–vaginal sex with an HIV-infected woman in the US."

They highlight findings from a study of men attending a Baltimore sexually transmitted infection clinic, which found that whilst circumcision was not associated with a protective effect throughout the whole clinic population, it was associated with a reduced risk of infection among men known to have had unprotected sexual intercourse with HIV-positive female partners. The risk reduction was approximately 55%, although the confidence intervals of this estimate were wide (0.22–0.97) (Warner 2007).

‘Some sexually active men may consider circumcision as an additional HIV prevention measure, but should do so only in consultation with their physician or health care provider, and with a clear understanding of the costs and risks of circumcision.’

The need to continue using other prevention measures such as condoms also needs to be emphasised. Men who choose to be circumcised should also be counselled about the importance of waiting until would healing is complete before having sexual intercourse.
Circumcision as a HIV prevention measure might be particularly effective in US Black and Hispanic men, given currently higher HIV infection rates in these populations- plus the fact that circumcision is currently less common in these groups, they add.

Sullivan PS et al. Male circumcision for prevention of HIV transmission: What the new data mean for HIV prevention in the United States. 2007 PLoS Med 4(7): e223.

Warner L et al. Male circumcision and risk of HIV infection among heterosexual men attending Baltimore STD clinics: An evaluation of clinic-based data [presentation]. Society for Epidemiologic Research Meeting; 21–24 June 2006 ; Seattle, Washington, United States of America. Available: