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.
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.
Shaffer
Douglas N
DN
US Army Medical Research Unit, Walter Reed Project HIV Program, Kericho, Kenya. dshaffer@wrp-kch.org
Bautista
Christian T
CT
Sateren
Warren B
WB
Sawe
Frederick K
FK
Kiplangat
Stanley C
SC
Miruka
Argwings O
AO
Renzullo
Philip O
PO
Scott
Paul T
PT
Robb
Merlin L
ML
Michael
Nelson L
NL
Birx
Deborah L
DL
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