Circumcision appears to offer some protection against HIV, but not other sexually transmitted diseases (STDs), according to new research. The results support the idea that HIV interacts with the foreskin in ways unlike those of other STDs.
Previous studies have hinted that circumcised men have a reduced risk of catching HIV. But these studies also found that circumcised men had a lower risk of other STDs as well, suggesting that they may simply partake in fewer risky sexual behaviors than uncircumcised men, perhaps due to differences between cultures that encourage circumcision and those that don't. To determine whether circumcision leads to HIV-specific protection, epidemiologist Robert Bollinger of Johns Hopkins University in Baltimore collaborated with scientists at the National AIDS Research Institute in Pune, India.
The team followed nearly 2300 men who visited STD clinics in India and were HIV-free. About 10% of the men were circumcised. The researchers determined the rates at which the men became infected with HIV, gonorrhea, or syphilis. Controlling for risky sexual behavior, the researchers found that the men contracted gonorrhea and syphilis at roughly the same rates regardless of circumcision, but circumcised men were six to seven times less likely to acquire HIV, they report in The Lancet on 27 March. Bollinger says the specificity of circumcision to reduced HIV infection "provides a clue" as to why it works: "Other studies have shown that the foreskin has cells that are magnets for HIV." Removing the foreskin may hinder HIV but not other STDs, he says.
"It's a good study," says epidemiologist Stephen Moses of the University of Manitoba, Winnipeg. But he's still not convinced that circumcision protects against HIV infection. "Circumcision is a surgical procedure, it removes natural tissue, and it can cause harm," he says, so the evidence needs to be solid before doctors recommend it. He says the debate will be settled by three trials in which men are randomly grouped to receive circumcision or not and then followed to determine whether the procedure protects them from HIV.