Additionally, the treatment arm modified the association of 25(OH)D with prostate cancer among individuals with higher serum IGFBP-3 (OR, finasteride: 0.83, 95% CI: 0.61–1.12; OR, placebo: 1.26, 95% CI: 0.98–1.63; p for interaction = 0.03). This evidence concerns the gene IGFBP3 and prostate carcinoma.