The Effect of Growth Hormone (GH) Treatment on Forearm Muscle in GH-Deficient Children: Evidence Based on Peripheral Quantitative Computed Tomography Measurements

Conventional analyses of growth hormone (GH) treatment in children focus mainly on height development. We aimed to investigate the complex effects of GH on three components of the body, namely, muscle, fat and bone, by means of peripheral quantitative computed tomography. This method, in which a component of the body is taken to represent the whole, is non-invasive and suitable for children. Our study group comprised 74 pre-pubertal children with GH deficiency (mean age, 7.2 years; height standard deviation score [SDS], –2.9) who received recombinant human GH treatment (30 µg/kg/day [0.03 mg/kg/day]) for 12 months (55 of the children received treatment for up to 24 months). Within 2 years, mean height SDS increased from –2.9 to –1.5, muscle surface area SDS rose from –2.4 to 1.0, while fat surface area SDS decreased from 0.1 to –1.0. Grip strength SDS increased from –1.0 to –0.3, whereas the ratio of strength to muscle area did not change. We thus observed that changes in body compartments (including bone) occur during GH treatment; we also found evidence showing a specific pattern of dynamics over time. In view of the limited literature available on muscle development during GH therapy in children, we explore the potential role and significance of these response variables in the assessment of GH therapy.