Wednesday, July 18, 2007

The Protective Effect of Circumcision

...on HIV Incidence in Rural Low-Risk Men Circumcised Predominantly by Traditional Circumcisers in Kenya: Two-Year Follow-Up of the Kericho HIV Cohort Study.

J Acquir Immune Defic Syndr. 2007 Aug 1;45(4):371-379.

From the *US Army Medical Research Unit, Kericho, Kenya; †Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc, Rockville, MD; ‡Division of Retrovirology, Walter Reed Army Institute of Research/US Military HIV Research Program, Rockville, MD; §Kenya Medical Research Institute, Kericho, Kenya; and ∥Vaccine Research Center, National Institutes of Health, Bethesda, MD. ¶D. L. Birx is currently affiliated with the Global AIDS Program, US Centers for Disease Control and Prevention, Atlanta, GA.

BACKGROUND:: Three randomized controlled trials (RCTs) have demonstrated that male circumcision prevents female-to-male HIV transmission in sub-Saharan Africa. Data from prospective cohort studies are helpful in considering generalizability of RCT results to populations with unique epidemiologic/cultural characteristics.

METHODS:: Prospective observational cohort sub-analysis. A total of 1378 men were evaluated after 2 years of follow-up. Baseline sociodemographic and behavioral/HIV risk characteristics were compared between 270 uncircumcised and 1108 circumcised men. HIV incidence rates (per 100 person-years) were calculated, and Cox proportional hazards regression analyses estimated hazard rate ratios (HRs).

RESULTS:: Of the men included in this study, 80.4% were circumcised; 73.9% were circumcised by traditional circumcisers. Circumcision was associated with tribal affiliation, high school education, fewer marriages, and smaller age difference between spouses (P < 0.05). After 2 years of follow-up, there were 30 HIV incident cases (17 in circumcised and 13 in uncircumcised men). Two-year HIV incidence rates were 0.79 (95% confidence interval [CI]: 0.46 to 1.25) for circumcised men and 2.48 (95% CI: 1.33 to 4.21) for uncircumcised men corresponding to a HR = 0.31 (95% CI: 0.15 to 0.64). In one model controlling for sociodemographic factors, the HR increased and became non-significant (HR = 0.55; 95% CI: 0.20 to 1.49).

CONCLUSIONS:: Circumcision by traditional circumcisers offers protection from HIV infection in adult men in rural Kenya. Data from well-designed prospective cohort studies in populations with unique cultural characteristics can supplement RCT data in recommending public health policy.

Even a 'bush-job' in Africa reduces the risk of HIV infection for the circumcised to a third of that of the uncircumcised.