Circumcision at birth may help prevent prostate cancer in black men, with a stronger association also noted among men of all races circumcised after age 35, a study found.
Canadian researchers conducted an observational study of nearly 1,600 prostate cancer patients diagnosed in a Montréal hospital between 2005 and 2009, as well as more than 1,600 healthy controls.
Results appeared at BJU International.
Circumcised men had a slightly lower but not statistically significant risk of developing prostate cancer than uncircumcised men (OR, 0.89; 95% CI, 0.76 to 1.04). Circumcision did have a protective effect in men circumcised after age 35 (OR, 0.55; 95% CI, 0.30 to 0.98). A weaker protective effect was seen among men circumcised within 1 year of birth (OR, 0.86; 95% CI, 0.72 to 1.04).
Men circumcised after age 35 may have had a pathologic condition of the foreskin that lead to them being circumcised, an author noted.
Black men had the strongest protective effect (OR, 0.40; 95% CI, 0.19 to 0.86, P-value for interaction, 0.02). No association was found among other races.
“This is a particularly interesting finding, as black men have the highest rates of prostate cancer in the world and this has never been explained,” an author noted.
Circumcision may reduce the risk of contracting and maintaining a sexually transmitted infection, which has been postulated to be a risk factor for prostate cancer. This may explain the reduced risk of prostate cancer observed in males circumcised at a younger age prior to any potential exposure to infection.