Endocrine Abstracts

Type 2 diabetes mellitus is associated with increased prevalence of low serum testosterone levels in men [1]. Testosterone levels in men are known to be positively correlated with insulin sensitivity and negatively with visceral obesity. We performed a double blind placebo controlled crossover study to determine the effect of testosterone treatment on insulin resistance and glycaemic control in 24 hypogonadal men (10 patients treated with insulin) above age of 30 with Type 2 diabetes. Treatment was with intra-muscular testosterone 200 mg every two weeks or placebo given for 3 months in random order, followed by a washout period of 1 month before the alternate treatment phase. The primary outcomes were changes in fasting insulin sensitivity [as measured by homeostatic model index (HOMA)], fasting blood glucose and glycated haemoglobin. The secondary outcomes were changes in body composition, fasting lipids and blood pressure. Statistical analysis was performed on the delta values with the treatment effect of placebo compared against the treatment effect of testosterone using t-test.

Testosterone therapy reduced the HOMA index (−1.73±0.67, P=0.02, n=14) indicating an improved fasting insulin sensitivity. Glycated hemoglobin was also reduced as a result of reduction in insulin resistance (−0.37±0.17%, P=0.03). Testosterone treatment also resulted in a reduction in visceral adiposity as assessed by waist circumference (−1.63±0.71 cm, P=0.03). Total cholesterol decreased with testosterone therapy (−0.4±0.17 mmol/l, P=0.03) but no effect on blood pressure was observed.

Our data thus show a beneficial effect of testosterone therapy on integral components of the diabetic state in men. Improvements in glycaemic control, insulin resistance, cholesterol and visceral adiposity together represent an overall reduction in cardiovascular risk.