Bone mineral density in early-onset hypogonadism and the effect of hormonal replacement

Hypogonadism is associated with reduction of bone mineral density (BMD), especially if sex steroid deficiency occurs early in life. In this situation, the effect of hormonal replacement therapy on bone mass is controversial. We evaluated the BMD through dual-energy X-ray absorptiometry (DXA) in patients with genetically determined hypogonadism or hypogonadism acquired in adulthood. The results of the BMD of patients never treated (pretreatment) or under treatment were compared with population standards and were submitted to pair analysis. Thirty-three patients were evaluated: group 1: BMD evaluated pretreatment (24); group 2: BMD evaluated under treatment (21); group 3: BMD evaluated pretreatment and under treatment (12). In group 1, there was a significant reduction of bone mass in all regions, with no gender differences. In patients with concomitant growth hormone (GH) deficiency, the total body (-3.60) and lumbar spine (-4.10) BMDs were significantly reduced compared to patients without associated GH deficiency (-2.37 and -2.35, respectively). In group 2, a significant reduction of bone mass was detected in all regions. In group 3, the patients showed statistically significant improvement in BMD with hormonal replacement therapy in all regions in both sexes. We conclude that the early onset of hypogonadism reduces the BMD significantly. This effect is increased when there is associated GH deficiency. Gonadal steroid replacement therapy increases the BMD in all bone regions, and the increase is similar in both sexes. However, although hormone replacement improves bone mass, it still remains significantly lower in comparision with population standards.