Foreskin surface area and HIV acquisition in Rakai, Uganda

Foreskin surface area and HIV acquisition in Rakai, Uganda (size matters).

Male circumcision reduces HIV acquisition in men. The authors assessed whether foreskin surface area was associated with HIV acquisition prior to circumcision. In two randomized trials of male circumcision, the surface area of the foreskin was measured after surgery using standardized procedures. Nine hundred and sixty-five initially HIV-negative men were enrolled in a community cohort who subsequently enrolled in the male circumcision trials, provided 3920.8 person-years of observation prior to circumcision. They estimated HIV incidence per 100 person-years prior to circumcision, associated with foreskin surface area categorized into quartiles. Mean foreskin surface area was significantly higher among men who acquired HIV (43.3 cm2, standard error 2.1) compared with men who remained uninfected (36.8 cm, standard error 0.5, P = 0.01). HIV incidence was 0.80/100 person-years (8/994.9 person-years) for men with foreskin surface areas in the lowest quartile (< or ="26.3">45.6 cm2). Compared with men with foreskin surface areas in the lowest quartile, the adjusted incidence rate ratio of HIV acquisition was 2.37 (95% confidence interval 1.05-5.31) in men with the largest quartile of foreskin surface area. The risk of male HIV acquisition is increased among men with larger foreskin surface areas.

This retrospective cohort study is the first study examining the association between foreskin surface area and risk of HIV acquisition – and its findings are biologically plausible. Removing the foreskin reduces the risk of HIV acquisition by 50 to 60% because the only remaining unkeratinized mucosa on the penis after circumcision is the urethral meatus (opening). Before circumcision, more foreskin means more HIV target cells in the inner mucosa of the prepuce exposed to vaginal fluids during sex, likely more of the traumatic micro lesions that are open doors for HIV, and more genital ulcers that have welcoming mats out for HIV. In this study, risk of HIV acquisition in men with the largest foreskins was more than twice that of those with the smallest, leading to the claim that size matters. The larger your foreskin, the more you should think about getting it removed if you might be exposed to HIV now or later.