title: Impact of vitamin D supplementation on markers of bone mineral metabolism in term infants.
abstract: 25-Hydroxyvitamin D (25OHD) may influence bone turnover. We compared the dynamics of bone markers in 30 infants on vitamin D supplementation (≅550 IU/day) with different degrees of hypovitaminosis D (25OHD <11 ng/ml - deficiency vs. ≥ 11 <20 ng/ml - insufficiency). Baseline and follow-up (after 10 weeks), 25OHD, 1,25-dihydroxyvitamin D (1,25(OH)(2)D), 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. 331 IU; p<0.001), 1,25(OH)(2)D (48 vs. 95.5 pg/ml, p<0.001), OC (88.8 vs. 159.1 ng/ml, p<0.001), PINP (3886 vs. 2409 ng/ml; p<0.001), CTX (1.6 vs. 1.1 ng/ml; p<0.001), and NT-proCNP (75.1 vs. 35.1 pmol/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)(2)D (95% vs. 58%, p<0.05).
  
  
  CONCLUSIONS
  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 550 IU/day led to a marked increase of 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, ALP, phosphaturia or hypophosphatemia was not observed in the studied neonates.
authors: Department of Neonatology and Neonatal Intensive Care, The Children's Memorial Health Institute, 04-730 Warsaw, Al. Dzieci Polskich 20, Poland. j.kowalska@czd.pl
authors: Justyna
authors: J
authors: Czech-Kowalska
authors: Pawel
authors: P
authors: Pludowski
authors: Anna
authors: A
authors: Dobrzanska
authors: Edyta
authors: E
authors: Kryskiewicz
authors: Elzbieta
authors: E
authors: Karczmarewicz
authors: Dariusz
authors: D
authors: Gruszfeld
authors: Agata
authors: A
authors: Pleskaczynska
authors: Malgorzata
authors: M
authors: Golkowska
mesh_terms: D015415:Biomarkers / Q000378:metabolism*; D001846:Bone Development; D001842:Bone and Bones / Q000378:metabolism*; D019587:Dietary Supplements; D006801:Humans; D007231:Infant, Newborn; D008903:Minerals / Q000378:metabolism*; D014807:Vitamin D / Q000008:administration & dosage*
chemical_list: D015415:Biomarkers; D008903:Minerals; D014807:Vitamin D