Loss of bone and muscle mass are major findings of male hypogonadism. In order to determine the long-term effect of testosterone replacement therapy on spinal bone and muscles, the trabecular and cortical bone mineral density, vertebral body area and paraspinal muscle area were assessed by quantitative computed tomography in 32 testosterone-substituted patients, aged 18-74 years, with idiopathic hypogonadotropic hypogonadism (n=6), pituitary insufficiency (n=5), Klinefelter syndrome (n=12) or other forms of primary hypogonadism (n=9). They were followed for a mean period of 3.2+/-1.7 years (mean+/-S.D.), ranging from 1 to 7 years. A significant correlation between initial serum testosterone levels and bone mineral density was found in patients with congenital forms (r=0.58; P<0.05) but not in those with acquired forms. A significant increase in trabecular and cortical bone mineral density (P<0.001) was documented in the course of replacement therapy in all patients regardless of the type of hypogonadism and age of patients. A slight but significant increase in paraspinal muscle area was observed if all patients were taken together (P<0.01). The area of paraspinal muscle correlated with body weight (r=0.58; P<0.001) and moderately with trabecular bone mineral density (r=0.4; P<0.01). Its increase did not correspond to the change observed for trabecular and cortical bone mineral density. Vertebral body area did not change over time. It correlated only with height and weight but not with bone mineral density. In conclusion, testosterone therapy of hypogonadal men improves both trabecular and cortical bone mineral density of the spine independently of age and type of hypogonadism while vertebral area remains unchanged. The effects seen on paraspinal muscles emphasize the clinical benefit of adequate replacement therapy for the physical fitness of hypogonadal men.
E Leifke, HC Korner, TM Link, HM Behre, PE Peters and E Nieschlag
E Leifke, M Friemert, M Heilmann, N Puvogel, C Smaczny, A von zur Muhlen and G Brabant
OBJECTIVE: Delayed sexual maturation and low body weight is common in cystic fibrosis (CF). Concomitant data on sex hormones and concomitant body composition are lacking in men with CF. DESIGN: Cross-sectional study. SUBJECTS AND METHODS: Serum levels of testosterone, 17beta-oestradiol (E(2)), 25-hydroxyvitamin D (25(OH)D), sex hormone-binding globulin (SHBG) and LH were measured by RIA and total and regional lean body mass (LBM), fat body mass (FBM), bone mineral content and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry, in men with CF (n=40; age 24.7+/-5.4 years) and age-matched healthy controls (n=28; age 25.7+/-3.7). Only men without acute disease exacerbation or systemic glucocorticoid treatment were included. RESULTS: Mean levels of hormonal serum parameters differed significantly between healthy controls (testosterone=20.2+/-5.5 nmol/l; E(2)=95.0+/-20.2 pmol/l; 25(OH)D=62.8+/-28.3 nmol/l) and patients (testosterone=15.9+/-4.1 nmol/l; E(2)=60.7+/-19.4 pmol/l; 25(OH)D=39.5+/-17.8 nmol/l; P<0.001) while no difference was found for SHBG or LH. Eleven (for E(2), 19 of 40, for 25(OH)D, 20 of 40) out of 40 patients had serum testosterone levels 2 s.d. below the mean of normal. Men with CF showed a relative shift from FBM to LBM and a different body fat distribution compared with healthy controls (P<0.01). Testosterone was not correlated with weight, total or regional LBM or FBM, but significantly with BMD (r=0.32; P<0.05) independently from body height and 25(OH)D levels. E(2) was correlated with regional and total FBM (r=0.48; P<0.05). In a multiple regression analysis of the joint effect of testosterone and body components on E(2), a testosterone-independent effect was found for FBM. CONCLUSIONS: CF patients with stable disease have moderately reduced serum testosterone levels. This might already imply detrimental effects on bone. The change in LBM of patients appears to have no direct association with sex hormone levels while low FBM might cause reduced net conversion of serum testosterone to E(2) with possible effects on FBM distribution.