Bone mineral density in hypogonadal men remains low after long-term testosterone replacement

In 11 congenital hypogonadal men, the bone mineral density (BMD) values were determined to assess the effect of long-term androgen replacement therapy (ART) on skeletal integrity.

Eleven congenital hypogonadal men, including 8 isolated gonadotropin deficiency patients, 2 Kallmann's syndrome and 1 vanishing testes syndrome were recruited and treated with 250 mg of testosterone enanthate intramuscularly every 4 weeks for 7-43 years (mean+/-SD: 21.5 +/-13 years). In these patients and a group of 10 healthy young men (controls), the whole and trabecular BMDs were examined at the distal end of radius by means of a peripheral quantitative computerized tomography device.

The whole radial BMD in hypogonadal men was significantly less in the patients than in the healthy men (498+/-115 and 725+/-134 mg/cm(3), respectively; P<0.01); the trabecular BMD was also lower in the hypogonadal men (199+/-80 and 375+/-89 mg/cm(3); P< 0.01). The whole radial BMD values in 10 of 11 hypogonadal men were at least 1 SD below the mean value for healthy young men; 2 hypogonadal men had BMD values more than 2.5 SD lower than the healthy mean. Additionally, the whole radial BMD showed a significant negative correlation with the patient's age at the initiation of ART (r = 0.748, P<0.01). The serum level of bone-specific alkaline phosphatase and the urinary level of deoxypyridinoline were not significantly different between the two groups.

Osteopenia persists in the hypogonadal men after long-term ART, suggesting that such patients have a persistent defect in bone development not alleviated by androgen replacement.