title: 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.
abstract: 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.
authors.affiliation: US Army Medical Research Unit, Walter Reed Project HIV Program, Kericho, Kenya. dshaffer@wrp-kch.org
authors.forename: Douglas N
authors.initials: DN
authors.lastname: Shaffer
authors.forename: Christian T
authors.initials: CT
authors.lastname: Bautista
authors.forename: Warren B
authors.initials: WB
authors.lastname: Sateren
authors.forename: Frederick K
authors.initials: FK
authors.lastname: Sawe
authors.forename: Stanley C
authors.initials: SC
authors.lastname: Kiplangat
authors.forename: Argwings O
authors.initials: AO
authors.lastname: Miruka
authors.forename: Philip O
authors.initials: PO
authors.lastname: Renzullo
authors.forename: Paul T
authors.initials: PT
authors.lastname: Scott
authors.forename: Merlin L
authors.initials: ML
authors.lastname: Robb
authors.forename: Nelson L
authors.initials: NL
authors.lastname: Michael
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Birx
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002944:Circumcision, Male / Q000706:statistics & numerical data; D015331:Cohort Studies; D015658:HIV Infections / Q000453:epidemiology* / Q000517:prevention & control* / Q000821:virology; D015497:HIV-1; D006801:Humans; D015994:Incidence; D007630:Kenya / Q000453:epidemiology; D008297:Male; D016488:Medicine, African Traditional; D012307:Risk Factors; D012424:Rural Population; D012725:Sexual Behavior