Relationship of prostate-specific antigen to age and testosterone in men with type 2 diabetes mellitus.

OBJECTIVE

To determine whether prostate-specific antigen (PSA) concentrations in type 2 diabetic men with hypogonadotrophic hypogonadism are lower than those in eugonadal men with type 2 diabetes and whether PSA concentrations are related to plasma testosterone concentrations.

METHODS

In this cross-sectional study, we measured serum total testosterone, sex hormone-binding globulin, free testosterone, PSA, hematocrit, and hemoglobin A1c in consecutive type 2 diabetic men who presented to 2 endocrinology referral centers between January 2006 and January 2007. We collected other clinical and demographic data including age, height, weight, and ethnicity.

RESULTS

Of 400 eligible patients, 280 men met inclusion criteria. Plasma PSA concentrations were lower in type 2 diabetic men with low free testosterone concentrations than in those with normal free testosterone concentrations (0.89 +/- 0.07 ng/mL vs 1.10 +/- 0.08 ng/mL, [corrected] P = .011). PSA concentrations were positively related to age (r = 0.34, P<.001), total testosterone (r = 0.29, P<.001), free testosterone (r = 0.17, P = .02), and sex hormone-binding globulin (r = 0.22, P<.001) and negatively related to body mass index (r = -0.28, P<.001). In stepwise backward regression analysis, PSA concentration was predicted by age (P<.001) and free testosterone (P<.001), but not by body mass index or sex hormone-binding globulin.

CONCLUSIONS

Plasma PSA concentrations are lower in type 2 diabetic men with hypogonadism than in eugonadal men with type 2 diabetes, and plasma PSA is related to age, plasma total testosterone concentrations, and free testosterone concentrations in patients with type 2 diabetes.