Background: Children born SGA have been implicated to be at higher risk for subsequent obesity; however, the body composition, especially fat distribution, in SGS short stature (SGA-SS) patients and the effects of growth hormone (GH) therapy on body composition in SGA-SS have not been fully studied.
Purpose: To unravel the effects of GH therapy on body fat mass, body fat distribution, muscle mass, and bone mineral density (BMD) in SGA-SS.
Method: Thirty pre-pubertal subjects with SGA-SS (14 boys and 16 girls, mean age at GH commencement 4.1+/- 1.1 years old) were included. Data on cumulative dose of GH, height (HT)-SDS, BMI-SDS, IGF-1 SDS, body composition by DXA analysis, and fat distribution by abdominal CT analysis obtained before and 1-year after GH treatment were retrospectively evaluated based on medical records. Parameters of body composition included percent fat mass (%FM) and percent muscle mass (%MM). Bone size-corrected volumetric lumbar BMD (vBMD) was calculated. Statistical analysis was performed using paired t-test or Pearson's correlation analysis. This study was approved by the institutional ethical committee.
Results: HT-SDS prior to GH treatment (Pre-HT-SDS) was -2.75 +/- 0.43 SD and this was not associated with IGF-1 SDS or BMI-SDS. However, Pre-HT-SDS was positively and negatively associated with %MM)(r=0.59, P<0.001) and %FM(r=-0.58, P<0.001), respectively. vBMD showed no association with Pre-HT-SDS. Abdominal CT revealed that amounts of visceral (VAT) and subcutaneous adipose tissue (SAT) were not elevated (VAT 4.22cm2, SAT 11.36 cm2). These findings suggest that impaired acquirement of muscle mass may be pathogenically associated with the development of SGA-SS. Upon 1-year GH treatment, HT-SDS and IGF-1 SDS increased significantly, although ΔHT-SDS was not associated with ΔIGF-1 SDS. Cumulative GH dose showed weak association with ΔHT-SDS (r=0.38, P<0.05). %FM significantly decreased by GH treatment, whereas GH treatment significantly increased %MM and vBMD. Abdominal CT showed that the amount of VAT slightly increased after GH therapy (5.32 cm2), but the value still resided within the normal reference levels. Amount of SAT was not affected (9.36 cm2). These results suggest that decreases in %FM by GH treatment was mainly caused by increases in muscle mass and bone mineral density.
Conclusion: GH therapy in children with SGA-SS increased HT-SDS and this was associated with improvement of body composition by increasing muscle mass and bone mineral density rather than reducing fat mass.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology