Hypogonadal obese men with and without diabetes mellitus type 2 lose weight and show improvement in cardiovascular risk factors when treated with testosterone: an observational study.

Background: Treatment of obesity with diet and exercise may have short-term success but longer-term maintenance of weight loss is less successful. Obesity is associated with a reduction of serum testosterone, and, vice versa, a reduction in serum testosterone is associated with obesity and features of the metabolic syndrome.

Objective: To investigate whether restoring serum testosterone to normal in hypo-gonadal obese men is beneficial with regard to weight loss and improvement of the metabolic syndrome.

Methods: A prospective registry accumulated to 181 men over five years (mean serum testosterone 10.06±1.3 nmol/L (N>12.1), body mass index (BMI) ≥30 kg/m2. Of these men, 72 had diabetes mellitus type 2. All received parenteral testosterone undecanoate 1000 mg/12 weeks for up to five years.

Results: Waist circumference (cm) decreased from 111.2±7.54 to 100.46±7.1, weight (kg) from 114.71±11.59 to 93.2±8.49, BMI (kg/m2) from 36.72±3.72 to 30.2±2.59 (all variables statistically significant vs. baseline (p<0.0001) and each year compared to the previous year (p<0.0001)). In the 72 diabetic men, waist circumference (cm) decreased from 112.93±7.16 to 101.48±7.24, weight (kg) from 116.94±11.62 to 94.42±9.42, BMI (kg/m2) from 37.71±3.5 to 30.95±2.69 (all variables statistically significant vs. baseline (p<0.0001) and each year compared to the previous year (p<0.0001)). In all men serum glucose, HbA1c, lipid profiles and blood pressure improved significantly. Testosterone treatment as assessed by hemoglobin, hematocrit, serum prostate specific antigen (PSA) and occurrence of prostate cancer was acceptably safe.

Conclusions: Normalizing serum testosterone in obese hypogonadal men, also in those with diabetes type 2, improved their metabolic state.