KLK3 and benign prostatic hyperplasia: After stratification by PSA quartiles, the incidence of BPH remained elevated in the highest PRS quartile (Q4) compared to the lowest (Q1) within the highest PSA quartile (Q4) group (OR = 1.75, 95% CI = 1.279–3.096, p = 0.001) and the third PSA quartile (Q3) group (OR = 1.39, 95% CI = 0.988–1.915, p = 0.010) (see Fig. 1B).