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

Male circumcision reduces HIV acquisition in men. We 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. We 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 cm2), 0.92/100 person-years (9/975.3 person-years) with foreskin areas in the second quartile (26.4-35.0 cm2), 0.90/100 person-years (8/888.5 person-years) with foreskin area in the third quartile (35.2-45.5 cm2) and 2.48/100 person-years (23/926.8 person-years) in men with foreskin surfaces areas in the highest quartile (>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.