Clinical and biochemical assessment of hypogonadism in men with type 2 diabetes: correlations with bioavailable testosterone and visceral adiposity.

OBJECTIVE: The aim of our study was to assess the prevalence of clinical hypogonadism, based on both symptoms and biochemical available measures of testosterone deficiency, in men with type 2 diabetes.

RESEARCH DESIGN AND METHODS: In a cross-sectional study of 355 type 2 diabetic men aged >30 years, total and bioavailable testosterone, sex hormone-binding globulin, BMI, and waist circumference were measured and free testosterone was calculated. Overt hypogonadism was defined as the presence of clinical symptoms of hypogonadism and low testosterone level (total testosterone <8 nmol/l and/or bioavailable testosterone <2.5 nmol/l). Borderline hypogonadism was defined as the presence of symptoms and total testosterone of 8-12 nmol/l or bioavailable testosterone of 2.5-4 nmol/l.

RESULTS: A low blood testosterone level was common in diabetic men, and a significant proportion of these men had symptoms of hypogonadism. Overt hypogonadism was seen in 17% of men with total testosterone <8 nmol/l and 14% with bioavailable testosterone <2.5 nmol/l. Borderline hypogonadism was found in 25% of men with total testosterone 8-12 nmol/l and bioavailable testosterone between 2.5 and 4 nmol/l; 42% of the men had free testosterone <0.255 nmol/l. BMI and waist circumference were both significantly negatively correlated with testosterone levels in men, with the association being stronger for waist circumference.

CONCLUSIONS: Testosterone levels are frequently low in men with type 2 diabetes, and the majority of these men have symptoms of hypogonadism. Obesity is associated with low testosterone levels in diabetic men.