[Study of bone mass in patients with growth hormone deficiency]

To evaluate bone mineral density by radiogrametric study of metacarpal bone diameter and cortical thickness in patients with growth hormone deficiency (GHD) before and during treatment with growth hormone (GH).

We studied 92 children with GHD (60 boys and 32 girls) divided into two groups: group I: 66 previously untreated patients (42 boys and 24 girls) aged between 3 and 14 years old; group II: 66 patients (42 girls and 24 boys) treated with GH and with a mean age of 10.2 +/- 3.1 years at treatment onset. Bone mass was studied indirectly by radiogrametry; the bone diameter and cortical thickness of the 2nd-3rd and 4th metacarpal bones were measured with a magnifying glass. As reference standards we used the Spanish longitudinal growth and development study (Andrea Prader Center, Zaragoza) in children aged between 0.5 and 9 years and the Swiss longitudinal standards in children aged 10 years of age and older. Statistical significance was set at p < 0.05.

Group I (spontaneous evolution): cortical thickness values were below the mean with statistically significant differences al 11, 12 and 13 years of age in girls and at 12, 13 and 14 years in boys. Bone diameter was diminished compared with controls in all the study periods and was significantly reduced at 8, 9, 10 and 11 years of age in girls and at 8, 10, 11, 12, 13 and 14 years in boys. Group II: (effect of GH treatment): cortical regression analysis showed a sharp increase in the first year of treatment with a subsequent moderate increase, which was statistically significant. Bone diameter showed a similar pattern with a significant increase which was more pronounced in the first period.

Children with GHD have decreased bone mass before initiation of treatment and therefore show deficient acquisition of peak bone mass, which in normal conditions occurs during in the first 4-5 years of life and during adolescence. GH replacement therapy leads to recovery of bone mass, which is more pronounced in the first year of treatment and prevents the progressive reduction that appears in untreated patients. Therefore, GH treatment plays an important role in peak bone mass acquisition in children with GHD.