In the univariate analysis, the prostate cancer diagnosis rate was significantly increased with low vitamin D levels (Odds ratio [OR], 0.975; P < 0.001) and other factors such as small prostate total volume (OR, 0.983; P < 0.001), young age (OR, 0.993; P < 0.001), low BMI (OR, 0.978; P < 0.001), and high serum PSA levels (OR, 1.063; P < 0.001). This evidence concerns the gene KLK3 and prostate cancer.