Analysis of studies that examined the association between diabetes mellitus and prostate cancer. Analysis of studies that examined the association between diabetes mellitus and prostate cancer. RRs and 95% CI for all studies and the overall effect estimate are reported in the log scale. Among diabetics, the overall RR for prostate cancer is statistically significant at 0.84 (95% CI, 0.76-0.93). Jocelyn S. Kasper, and Edward Giovannucci Cancer Epidemiol Biomarkers Prev 2006;15:2056-2062 ©2006 by American Association for Cancer Research