Long-term prospective study of body composition and lipid profiles during and after growth hormone (GH) treatment in children with GH deficiency: gender-specific metabolic effects

Abstract

GH has many effects on metabolism in addition to promoting growth. We studied changes in body composition and lipid profiles during and after GH treatment in 94 children with GH deficiency. Sixty-two subjects (46 boys and 16 girls) were evaluated at the beginning and during 36 months of GH treatment. The other 32 (21 boys and 11 girls) who had already been treated with GH were examined after the discontinuation of GH for a 6-month period. The height SD scores at the beginning and the discontinuation of GH treatment were -2.81 and -1.34 in boys and -3.14 and -1.38 in girls, respectively. The percent body fat (BF) significantly decreased from 16.5% to 11.7% in boys and from 16.7% to 11.6% in girls during the first 6 months of GH treatment (P < 0.01). BF subsequently remained constant in boys, but started to increase in girls from the 18th month of treatment. Lean body mass (kilograms) increased linearly throughout the treatment in both sexes (P < 0.01). Mean total cholesterol (TC) values decreased as a result of marked declines in low density lipoprotein cholesterol in both sexes, although statistical significance was detected only in boys (P < 0.01). High density lipoprotein cholesterol (HDLC) and apolipoprotein AI (Apo-AI) rapidly increased only in boys (P < 0.01). Triglyceride, Apo-AII, Apo-B, Apo-CII, Apo-CIII, Apo-E, and lipoprotein(a) showed no significant changes compared with baseline levels. Mean TC/HDLC and Apo-B/Apo-AI ratios decreased during treatment in both sexes, but the difference from baseline was significant only in boys (P < 0.01). After discontinuation of GH treatment, BF increased, and lean body mass decreased in boys (P < 0.01), whereas these variables did not change in girls. TC and low density lipoprotein cholesterol increased in boys within 6 months of discontinuing GH (P < 0.05). Other lipoproteins did not change in either sex, except for lipoprotein(a), which decreased significantly 6 months after the cessation of GH treatment in boys (P < 0.01). The mean TC/HDLC and Apo-B/Apo-AI ratios increased in boys slightly, but insignificantly. We concluded that GH treatment has beneficial effects on body composition and lipid profiles in both boys and girls with GH deficiency, although there are considerable gender differences. These beneficial effects of GH were reversed after the discontinuation of GH treatment, suggesting an important role of GH for GH-deficient children in the maintenance of normal metabolism even after the completion of linear growth.