Height, muscle, fat and bone response to growth hormone in short children with very low birth weight (VLBW) born appropriate for gestational age (AGA) and small for gestational age (SGA)

Abstract

BACKGROUND/AIMS:

Growth hormone (GH) treatment is approved for short children born SGA but not for AGA. Our aim was to study the effect of GH in short VLBW SGA and AGA children. METHODS:

The study group comprised 44 prepubertal short children with a birth weight <1,500 g: 27 AGA (12 females) and 17 SGA (6 females). Mean values at GH start were (AGA, SGA): age 6.94, 7.14 years, height standard deviation score (SDS) -3.33, -3.33, and GH dose (mean ± SD) 54 ± 12, 51 ± 11 µg/kg/day. Arm and calf cross-sectional muscle area using peripheral quantitative computer tomography, body composition data using dual-energy X-ray absorptiometry and body impedance assessment, maximal isometric grip force and skin fold thickness, IGF-1 and IGFBP-3 were measured at the start and after 12 months of GH. RESULTS:

At GH start, both groups had similar characteristics with low height, weight, height velocity, muscle mass, bone thickness and content. The first year of GH treatment led to changes in muscle area SDS (AGA, SGA) -2.23 to -0.73 (p = 0.0010), -3.18 to -1.17 (p = 0.060) (AGA vs. SGA p = 0.61), fat area SDS -1.06 to -1.83 (p = 0.054), -0.62 to -1.75 (p = 0.12) (AGA vs. SGA p = 0.65) and height velocity SDS -0.0015 to 4.2 (p < 0.0001), -0.18 to 3.3 (p < 0.0001) (AGA vs. SGA p = 0.36). CONCLUSIONS:

Growth, muscle and fat mass are similarly impaired in short prepubertal AGA and SGA VLBW children. The children born AGA show a similar or better response to GH compared to those born SGA. These results reveal the arbitrary nature of using the criterion 'SGA' for eligibility to GH treatment in children born with a birth weight <1,500 g.