July 2, 2010
A recent study finds circumcised men were less likely than their uncircumcised peers to report penile cuts, abrasions, and other injuries from sex -- perhaps helping explain why circumcision is linked to a lower risk of female-to-male HIV transmission.
Investigators led by Dr. Supriya D. Mehta of the University of Illinois at Chicago analyzed data from almost 2,800 Kenyan men ages 18-24 randomly assigned to undergo circumcision or remain uncircumcised. At the end of two years, circumcised men were 61 percent as likely (95% CI 0.54-0.68) to report any type of any injury during sex (defined as soreness during sex, penile scratches, cuts or abrasions during sex, and bleeding of the skin of the penis after sex.)
The researchers discussed why penile injuries may affect the transmission of HIV. One theory is that circumcision reduces the amount of mucosal tissue exposed during sex and therefore limits HIV's access to susceptible cells. Another possibility is that thickened skin around the circumcision scar blocks HIV.
The current study addressed the premise that mild injuries such as cuts and scratches could provide an entry to HIV.
Overall, penile injury was common; at baseline, 64 percent of the men reported some type of soreness, abrasion or bleeding associated with sex in the past six months.
Men who were more likely to report injuries were older, had multiple recent sex partners, were positive for the genital herpes virus (HSV-2) and had genital ulcers. Fewer injuries were reported among men who used condoms, cleaned the penis soon after sex, and were monogamous.
The full report, "Circumcision and Reduced Risk of Self-Reported Penile Coital Injuries: Results from a Randomized Controlled Trial in Kisumu, Kenya," was published in the Journal of Urology (2010;184(1):203-209).