Diabetes mellitus is associated with subnormal serum levels of free testosterone in men


Ernani L. Rhoden, Urology, Federal Foundation of Medical Sciences of Porto Alegre, Porto Alegre. RS, Brazil.
e-mail: ernanirhoden@yahoo.com.br



To evaluate the relationship between diabetes mellitus (DM) and serum levels of free (FT) and total (TT) testosterone.


A cross-sectional study was carried out including 746 men, of whom 116 (15.6%) were diabetics. Both groups, diabetic and nondiabetic, were paired according to age. Body mass index (BMI) and waist-to-hip ratio (WHR) were calculated, and a stratification analysis correlating DM and elevated BMI (>25 kg/m2) and WHR (>1) with the presence of subnormal FT and TT levels was performed.


FT and TT serum levels were subnormal in 46% and 34% of diabetics, respectively, and in 24% and 23% of nondiabetics. Subnormal FT levels were strongly correlated with DM (odds ratio (OR) 2.7; 95% confidence interval (CI) 1.8–4.1) but not with elevated BMI (OR 1.4; 95% CI 1.0–2.0). Subnormal TT levels were more strongly associated with elevated BMI and WHR (OR 2.6; 95% CI 1.7–3.9 and 2.0; 1.4–2.9) than with DM (1.7; 1.1–2.6 and 2.0; 1.3–3.2).


These data strongly suggest that DM is associated with subnormal FT levels, and that TT levels are influenced more by obesity and central adiposity.