Abstract:
Background
Male circumcision is a primary HIV-1 prevention intervention for men. It is uncertain whether male circumcision reduces the risk of syphilis among men and their female partners.
Methods
Using data from a prospective study among HIV-1 serodiscordant heterosexual couples from Kenya and Uganda, we assessed whether male circumcision was associated with incident syphilis in men and in their female partners. Multivariate Andersen-Gill survival methods were used, adjusted for age, sexual behavior, and plasma HIV-1 RNA levels of the HIV-1 infected partner.
Findings
4716 HIV-1 serodiscordant couples (37·5% with an HIV-1 infected male) were followed for a median of 2·75 years. At enrollment, 1575 (53·5%) HIV-1 uninfected and 560 (32·4%) HIV-1 infected men were circumcised; an additional 69 (4·2%) HIV-1 infected and 132 (4·8%) HIV-1 uninfected men became circumcised during study follow up. 221 incident syphilis infections were observed: 46 among HIV-1 infected men (incidence 1·10 per 100 person-years), 76 among HIV-1 uninfected men (1·09 per 100 person-years), 54 among HIV-1 infected women (0·77 per 100 person-years) and 45 among HIV-1 uninfected women (1·11 per 100 person-years). Male circumcision was associated with a 42% reduction in incident syphilis in men (adjusted hazard ratio [aHR] 0.58 95% CI 0·37–0·91) including a 62% reduction among HIV-1 infected men (aHR 0·38, 95% CI 0·18–0·81) and a non-significant reduction in incident syphilis among HIV-1 uninfected men (aHR 0·64, 95% CI 0·36–1·11). Among women, circumcision of their male partners was associated with a 59% reduction in incident syphilis (aHR 0.41 95% CI 0.25–0.69), including a 75% reduction among HIV-1 uninfected women (aHR 0·25, 95% CI 0·08–0·76) and a 48% reduction among HIV-1 infected women (aHR 0·52, 95% CI 0·27–0·97).
Interpretation
In this large prospective cohort study among HIV-1 serodiscordant couples, male circumcision was associated with decreased risk of incident syphilis in men and women. If confirmed, these results suggest that medical male circumcision could substantially reduce incidence of syphilis and its sequelae.