[Study of bone mass in Turner syndrome]

To evaluate bone mass in patients with Turner syndrome by measuring metacarpal cortical thickness and bone diameter before and after treatment with oxandrolone, growth hormone (GH) and estrogens.

We studied 42 girls with Turner syndrome divided into the following groups: group I: 31 patients aged between 3 and 15 years who were not treated before the study; group II: 15 patients treated with GH at start ages of between 5.2-14.8 years; group III: 17 patients treated with oxandrolone at start ages of between 5.3 and 15.2 years; group IV: 17 patients treated with estrogens and divided in different subgroups: IVa: seven patients treated with GH and estrogens at start ages of between 6.1 and 12.9 years; IVb: five patients treated with oxandrolone and estrogens at start ages of between 13.4 and 17.4 years, and IVc: five patients treated with oxandrolone, GH and estrogens at start ages of between 10.3 and 16.1 years. Bone mass was evaluated by a radiogrammetric method that measures the cortical thickness and bone diameter of three metacarpal bones with a magnifying glass. The results are expressed in SD according to Spanish longitudinal reference standards (Andrea Prader Center of Growth and Development) from 0.5 to 9 years of age and to Swiss standards from the age of 10 years onwards. Statistical significance was set at p < 0.05.

Group I (spontaneous development): cortical development was below the mean and was significantly diminished at the ages of 9, 13 and 14 years; bone diameter was decreased in relation to controls throughout the study period; group II (impact of GH treatment): cortical thickness showed a nonsignificant increase of 0.6 SD from baseline to years 3-4 of treatment and diameter increased by 0.5 SD from baseline to year 4 of treatment; group III (impact of oxandrolone): cortical thickness increased from -0.8 SD before treatment to 0.0 SD at years 2 and 3 of treatment; bone diameter increased from -1.5 SD at baseline to -1 SD at 3 years of treatment; group IV (impact of treatment with estrogens); IVa: cortical thickness and bone diameter increased; IVb: cortical thickness increased but bone diameter was unchanged; IVc: both cortical thickness and bone diameter increased.

The results of this study show that cortical thickness and bone diameter are decreased in untreated girls with Turner syndrome; cortical thickness was significantly decreased at the ages of 9, 13 and 14 years, while bone diameter was diminished at all ages, suggesting the presence of osteopenia in these patients. GH treatment produced a nonsignificant increase in cortical thickness and bone diameter. Oxandrolone treatment showed a positive effect on bone mass during the first few years of therapy. Because of the small number of patients, conclusions cannot be reached on the effectiveness of estrogens.