A suggestion of effect modification by obesity for diabetes and high-grade prostate cancer was also found in the Reduction by Dutasteride of Prostate Cancer Events trial (odds ratios = 1.38 and 0.35, in obese and nonobese men, respectively; Pinteraction = .053), in which all men underwent protocol-driven prostate biopsies regardless of PSA levels (8). This evidence concerns the gene KLK3 and prostate cancer.