KLK3 and Alzheimer disease: In addition, we also observed that the AD cohort had a significantly higher percentage than the non-AD cohort to undergo prostate specific antigen (PSA) testing, regardless of the age group (30–44 years, 7.83% vs. 2.92%; 45–54 years 32.0% vs. 12.1; 55–64 years, 46.2% vs. 25.2%; ≥65 years, 54.5% vs. 35.9%) (Table 5).