To understand further the physiologic characteristics of serum prostate-specific antigen (PSA) concentrations in healthy younger men.

A total of 2032 men, 20 to 39 years old, who visited our hospital for a routine health checkup were entered into the study. Pearson correlation coefficients were determined to evaluate the association between serum PSA and clinical parameters. Because of the log-normal distribution, the serum PSA levels were log-transformed for analysis.

Although the relationships were weak, significant negative correlations were noted between serum PSA and body weight (r = −0.107, P <0.001), body mass index (BMI; r = −0.131, P <0.001), aspartate aminotransferase (AST; r = −0.076, P = 0.001), alanine aminotransferase (ALT; r = −0.079, P = 0.001), gamma-glutamyltransferase (r = −0.046, P = 0.046), and creatinine clearance (r = −0.113, P <0.001). A positive correlation was found between serum PSA and creatinine (r = 0.053, P = 0.024). Age did not correlate with serum PSA level. The influence of clinical parameters on serum PSA was explored using multiple linear regression analysis. Using the stepwise method, all other explanatory variables, except BMI, AST, and creatinine were eliminated (log₁₀[PSA] = −0.124[BMI] + 0.063[creatinine] − 0.053[AST] + 0.097; r = 0.152, P <0.001).

BMI, creatinine, and AST may influence the serum PSA level in this population. However, because it was not clear that this group should be considered at high risk of prostate cancer in the future, additional longitudinal research is needed.