Bone Turnover Markers during Growth Hormone Therapy for Short Stature Children Born Small for Gestational Age

Growth hormone therapy (GHT) can improve growth velocity and final height, but can also accelerate the process of bone growth, which is related to structural bone modeling in both formation and resorption. This study evaluated the capacity of bone turnover markers to predict early growth response to one year of GHT in short stature children born small for gestational age (SGA). This study included 25 prepubertal children born SGA. We estimated P1NP (N-terminal procollagen type 1), CTX (C-terminal telopeptide of collagen type 1), P3NP (N-terminal procollagen type 3), NT-pro-CNP (amino-terminal C-type natriuretic peptide) and Ca-P metabolism using standard ECLIA (electrochemiluminescence), RIA (radioimmunoassay), and ELISA (enzyme-linked immunosorbent assay) methods. A statistically significant increase in bone resorption markers (CTX) was found at both 6 and 12 months. P1NP bone markers were increased at 6 months and after 12 months of therapy. The P3NP marker for collagen synthesis also increased after 12 months of therapy. We obtained significant increases in phosphorus levels at 6 and 12 months, and similar ALP (alkaline phosphatase) increases. We found a significant correlation between height (cm) and CTX after 6-12 months, as well as a P1NP/height (SD) correlation after 12 months. Calcium levels significantly correlated with height (SD) after 12 months. We found strong reactions of bone resorption and bone formation markers during growth hormone therapy, which may determine their selection as predictors of GHT outcome in children born SGA. However, the issue requires further research.