Changes in body proportions and body fat content in GH-deficient and non-GH-deficient children during the first year of growth hormone treatment.

Introduction: The growth hormone/insulin-like growth factor-1 axis (GH/IGF-1) is crucial for longitudinal bone growth and exerts several metabolic effects. It is debatable whether and how the recombinant human growth hormone (rhGH) treatment affects the trunk-limb proportions. Aim of the study: We aim to evaluate the changes in body proportions and body fat content in short children with growth hormone deficiency (GHD), children born small for gestational age (SGA), and girls with Turner syndrome (TS) during the first year of rhGH therapy. Material and methods: The data of 70 children with GHD, 40 children born SGA, and 36 girls with TS from 1998 to 2019 were analyzed. The following parameters were measured: height, body weight, sitting height, and two skinfolds on the arm above the triceps brachii and below the scapula at the beginning of rhGH therapy and after the first year of treatment. Sitting height and lower limb length were presented as percentages (%) of body height. Fat mass percentage (%FAT) was calculated using the Slaughter formula. Results: At the beginning of rhGH, TS girls had the greatest height deficit (-2.7 SDS), the highest sitting height (%), and the lowest lower limb length (%) compared to children with GHD and children born SGA. Moreover, TS girls had higher body weight SDS, BMI SDS compared to SGA children (p < 0.001), and higher %FAT compared to both GHD and SGA children (p < 0.001 for both). After the first year of rhGH therapy, a significant increase in lower limb share (%) and a decrease in %FAT were observed in all the study groups. TS girls still had significantly higher sitting height (%), shorter lower limbs (%), and higher %FAT, body weight SDS, and BMI SDS compared to children with GHD and children born SGA (p < 0.05 for all variables). Conclusions: Our results show that rhGH treatment could increase lower limb length in relation to height and reduce fat mass in treated children. Girls with TS had the largest baseline body disproportions and the highest body fat content. Despite a satisfactory reduction in height deficit, after the first year of rhGH therapy, these girls had still higher body weight SDS, BMI SDS, %FAT, the highest sitting height (%), and the lowest lower limb length (%) compared to children with GHD and born SGA.