Study published in The Journal of Infectious Diseases, 2009; 200:000–000. DOI: 10.1086/648376. The authors found a correlation of reduced incidence of syphilis among men who reported predominantly insertive unprotected anal intercourse.
Results. Circumcision was not associated with prevalent or incident herpes simplex virus 1, herpes simplex virus 2, or self-reported genital warts. There was also no independent association of circumcision with incident urethral gonorrhea or chlamydia. Being circumcised was associated with a significantly reduced risk of incident (hazard ratio, 0.35 [95% confidence interval, 0.150.84]) but not prevalent (odds ratio, 0.71 [95% confidence interval, 0.351.44]) syphilis. The association was somewhat stronger among men who reported predominantly insertive unprotected anal intercourse (hazard ratio, 0.10 [95% confidence interval, 0.010.82]).
Conclusions. These are the first prospective data obtained from homosexual men to assess circumcision status as a risk factor for STIs. Circumcised men were at reduced risk of incident syphilis but no other prevalent or incident STIs. Circumcision is unlikely to have a substantial public health impact in reducing acquisition of most STIs in homosexual men.