Effect of nutrition on growth in short stature before and during growth-hormone therapy

Objective. Although nutritional counseling is an integral part of the management of rapidly growing children, few studies have focused on the importance of nutritional supervision during growth-hormone (GH) therapy. The objective of this study was to study the effect of caloric intake on growth before and during GH therapy. Methods. A total of 115 short normal prepubertal children who were 7.4 ± 1.2 years of age (mean ± SD) and had height SD score (SDS) of -2.5 ± 0.6 were treated with a GH dose range of 0.13 to 0.52 mg/kg per week for 1 year. A 3-day nutritional recall and blood chemistry analysis were repeated every 3 months. Results. Caloric intake (expressed as % recommended dietary allowance) was positively correlated with the pretreatment growth velocity (SDS) and the increment in growth velocity SDS during the first year of GH therapy (r = 0.363 and 0.493). By stepwise regression analysis, we identified 4 parameters that could predict the 1-year increment in growth velocity SDS: the contribution of each factor (% variability) was pretreatment growth velocity SDS 36%, GH dose (27%), caloric intake 4%, and the integrated concentration of GH 2% (r² = 0.689). GH therapy induced an alkaline phosphatase increment of 59 ± 49 IU/mL, an insulin-like growth factor-I increment of 32.6 ± 11.9 nmol/L, and a GH binding protein increment of 10.2 ± 2.7%. During GH therapy, an increase in serum transferrin (56.5 ± 35.2 mg/dL) and a decrease in serum iron (20.5.5 ± 20.2 μg/dL) were noted. These changes could not be detected through hemoglobin levels or hematopoietic indexes. Dietary iron supplementation reversed this phenomenon. Conclusions. The nutritional status of GH-treated patients before and throughout the course of GH treatment should be monitored closely to improve the growth response and prevent nutritional deficiencies. Special emphasis should be placed on iron nurture.