Uncircumcised men have an eight fold higher risk of becoming infected with HIV compared to circumcised men, according to a study of 2298 Indian men presented on Thursday at the 41st Annual Meeting of the Infectious Diseases Society of America by Dr Steven Reynolds of Johns Hopkins University, Baltimore.
The research was part of a larger study investigating risk factors for HIV-1 infection based on men attending one of three STD clinics in Pune, India. Between 1993 and 2000, 2,298 men who tested negative for HIV-1 were enrolled in the study. During subsequent visits (an average of three visits in 11 months), 2 of 191 men who were circumcised and 165 of 2,107 who were uncircumcised tested positive for HIV.
Demographics, sexual risk behaviours (including having sex with a prostitute), and condom use were remarkably similar between both groups, said Dr. Reynolds. Despite the similarity in risk profiles, researchers determined the incidence rate of HIV-1 among circumcised men it was 0.7 percent, whereas among uncircumcised men it was 5.5 percent, an 8-fold increase. The relative risk of infection among circumcised men, after adjusting for calendar year, age group, level of education, marital status, living with family, multiple sex partners, sex worker partners, condom use, tattoos, and medical injections, was 0.12 (p=0.003).
However, the study did not find circumcision to be protective against other sexually transmitted diseases, including syphilis, genital herpes and gonorrhoea.
The findings suggest the benefit of circumcision may be biological rather than due to other factors, such as differences in behavior between circumcised and uncircumcised men, or the possibility that circumcision promotes the acquisition of sexually transmitted infections, said Dr. Reynolds. The inner surface of the foreskin is not as thickly “keratinised” as the outside or other surfaces of the penis, meaning it has less of a protective layer and may be more easily penetrated by HIV, he said. It also has higher numbers of the cells that HIV infects, possibly contributing to the reduced risk of HIV infection observed when the foreskin is removed.
There are other potential methods uncircumcised men may be able to use to protect themselves against HIV, said Dr. Reynolds. In the future, a topical microbicide product might be applied to the foreskin before sex to protect against HIV. Such products are currently in development.
Circumcision isn’t totally protective and may not be culturally acceptable or safe in some settings, so regular condom use is still the best way of protecting against HIV and other sexually transmitted diseases, said Dr. Reynolds. Condom promotion remains a key strategy in the current fight against the spread of AIDS, he said.
“Circumcision as a potential prevention strategy requires confirmation by randomised clinical trials, which are the gold standard in evaluating medical interventions,” he said. There currently are clinical trials underway in Uganda, Kenya and South Africa.
Reynolds SJ et al. Male circumcision is protective against HIV-1 but not other common sexually transmitted infections in India. 41st Annual Conference of the Infectious Diseases Society of America, San Diego, 2003.