Endocrine Abstracts

Background: Testosterone replacement therapy in severe hypogonadism is indicated, however, the treatment of late onset hypogonadism (LOH) is debated, especially what the diagnostic criteria should be. In LOH bio-available testosterone probably gives a more accurate index of gonadal status as a diagnostic criterion as it takes SHBG into consideration. SHBG is known to increase with ageing, however, SHBG is also negatively influenced by insulin and visceral adiposity.

Aim: To investigate the anabolic effects of testosterone in ageing men with bio-available testosterone below the cut-off limit for young males (Nielsen et al. JCEM 2006) and waist circumference above 94 cm.

Patients and methods: A double-blinded, randomized, placebo-controlled 6 months study in men aged 68 (60–78) (mean and range) with bio available testosterone 4.9 (2.3–7.2) nmol/l and waist circumference 108 (95–128) cm.

Thirty-eight participants were randomized to placebo (n=18) or testosterone gel 50 mg/day (n=20).

Testosterone levels were measured by liquid chromatography tandem mass spectrometry after ether extraction and SHBG was measured by autoDELFIA assay. Bio-available testosterone was calculated according to Vermeulen et al. (JCEM 1999). Dual X-ray absorptiometry (DXA) was used to determine total lean body mass and total fat mass.

Statistics were performed on delta values (0–6 months). The Students t-test was used to compare mean delta values after 24 weeks of treatment.

Results: The randomization was successful. During the 6 months study total lean body mass increased significantly (P=0.004), in the testosterone treated group compared to placebo 1.73 (−1.1–6.2) kg versus −0.07 (−3.4–1.7) kg, respectively.

Total fat mass decreased significantly (P=0.037) in the testosterone treated group compared to placebo −1.2 (−3.6–3.8) kg versus 0.6 (−4.0–1.9) kg, respectively.

Conclusion: Testosterone therapy significantly increased total lean body mass and significantly decreased total fat mass in ageing men with relatively low bio-available testosterone and waist circumference above 94 cm.