Endocrine Abstracts

Growth hormone deficiency (GHD) impairs bone mass and strength. Androgen deficient men exhibit impaired bone mass, but the extent to which testosterone replacement can prevent this remains disputable. The aim of this study was to assess whether androgen deficiency presents an additional risk factor for bone health in male patients with GHD and whether this is correctable by testosterone substitution.

A group of 81 male patients with GHD, not receiving GH replacement, aged 49.6±1.7 years, with BMI of 28.23±0.61 kg/m², was divided in 3 groups according to androgen deficiency status: (1) androgen sufficient men with isolated GHD (n=16) (2) hypogonadal men not receiving any androgen replacement (n=15) and (3) hypogonadal men on androgen replacement (n=50). Lumbar spine BMD and Lumbar spine Z-score (Hologic DXA) were analyzed as well as markers of bone turnover – serum osteocalcin (OC) and beta-cross-laps (BCL).

Lumbar spine BMD was greater in the androgen replaced than in unreplaced hypogonadal GHD men (1.083±0.201 vs 0.950±0.136 g/cm²; P>0.05) but both groups had lower BMD than androgen sufficient (isolated GHD) group (1.120±0.218 g/cm²). Lumbar spine Z-score in unreplaced hypogonadal GHD men was significantly lower than in androgen sufficient men (isolated GHD) (−1.88 vs 0.4; P<0.05) but Z-score was also lower in the androgen replaced hypogonadal men than in androgen sufficient men (isolated GHD) (−0.32 vs 0.4; P>0.05). Both OC (17.47±10.6 vs 18.21±9.64 ng/ml; P>0.05) and BCL (275±233 vs 282±221 pg/ml; P>0.05) were lower in the androgen replaced than in unreplaced hypogonadal GHD men.

In conclusion, the observed trends in bone density values point to androgen deficiency as probably presenting an additional risk factor for bone health in male patients with growth hormone deficiency, which can only be partially corrected by testosterone replacement.