KLK3 and diabetes mellitus: In this study, conducted on a representative sample of the general, non-institutionalized U.S. population, we identified a significant inverse correlation between PPI use and PSA values, after controlling for all available clinically meaningful regressors (age, race/ethnicity, BMI, concomitant therapy, diabetes, history of BPE) and excluding subjects with ongoing conditions affecting PSA levels (history of PCa, urinary tract infection, recent invasive maneuvers on the urinary tract).