The Strong Protective Effect of Circumcision against Cancer of the Penis
Figure 4
Fixed effects forest plot models of the unadjusted risk ratios for (a) any high-risk HPV and for (b) multiple high-risk HPV infections detected at the coronal sulcus/glans in circumcised and uncircumcised men. The data are derived from both observational studies and randomized trials, and include HPV prevalence and incidence estimates. The unadjusted risk ratios differ from the adjusted odds ratios reported in some studies, because the odds ratio does not approximate to the risk ratio with common disease outcomes such as HPV, and because adjustment for risk behaviors may affect estimates. Nevertheless, the findings are in general consistent across studies as indicated by the nonsignificant tests for heterogeneity and suggest that, in aggregate, circumcision may reduce any high-risk HPV infection by approximately 36%, and multiple high risk HPV infections by 57%.
