Impact of vitamin D supplementation on markers of bone mineral metabolism in term infants
Czech–Kowalska J et al. – Vitamin D supplements had little to no impact on markers of bone turnover in term infants in the first few months of life, with the exception of osteocalcin. Ten weeks of cholecalciferol supplementation at a dose of 550IU/day led to a marked increase of 25–Hydroxyvitamin D (25OHD) concentration. The magnitude of 25OHD increment was inversely related to vitamin D status at baseline. Irrespective of the severity of vitamin D deficiency, a secondary hyperparathyroidism with elevated iPTH, alkaline phosphatase (ALP), phosphaturia or hypophosphatemia was not observed in the studied neonates.Methods
- The authors compared the dynamics of bone markers in 30 infants on vitamin D supplementation (=550IU/day) with different degrees of hypovitaminosis D (25OHD <11ng/ml — deficiency vs. ≥11 <20ng/ml — insufficiency).
- Baseline and follow–up (after 10weeks), 25OHD, 1,25–dihydroxyvitamin D (1,25(OH)2D), alkaline phosphatase (ALP), PTH, osteocalcin (OC), N–terminal propeptide of type I procollagen (PINP), C–terminal telopeptide of type I collagen (CTX), and amino–terminal propeptide of C–type natriuretic peptide (NT–proCNP) were measured.
- None of the newborns had craniotabes, hypocalcemia or hyperparathyroidism.
- The median (Q1;Q3) 25OHD increased from a baseline of 8.45 (7;11.9) ng/ml to 54.6 (34.7;67.3) ng/ml (p<0.001).
- The baseline 25OHD negatively correlated with total increment of 25OHD (r=–0.54; p=0.002).
- There were changes in ALP (241 vs. 331IU; p<0.001), 1,25(OH)2D (48 vs. 95.5pg/ml, p<0.001), OC (88.8 vs. 159.1ng/ml, p<0.001), PINP (3886 vs. 2409ng/ml; p<0.001), CTX (1.6 vs. 1.1ng/ml; p<0.001), and NT–proCNP (75.1 vs. 35.1pmol/l; p<0.001).
- Vitamin D deficient infants at baseline, compared to the insufficient group, revealed significantly higher percentage changes for 25OHD (745% vs. 167%, p<0.0001), OC (113% vs. 40%, p<0.05) and 1,25(OH)2D (95% vs. 58%, p<0.05).