title: High-dose vitamin d intervention in infants--effects on vitamin d status, calcium homeostasis, and bone strength.
abstract: BACKGROUND
  Guidelines in Finland recommend 10 μg of vitamin D3 daily for all infants. Recent observations suggest that this may be insufficient to maintain optimal serum 25-hydroxyvitamin D (S-25-OHD).
  
  
  OBJECTIVE
  The aim of the study was to evaluate effects of various vitamin D doses and determine a dose ensuring S-25-OHD of at least 80 nmol/liter in infants without signs of vitamin D excess.
  
  
  METHODS
  We conducted a randomized double-blind intervention study. Cord blood was obtained at birth for S-25-OHD; 113 infants were randomized to receive vitamin D3 10, 30, or 40 μg/d from age 2 wk to 3 months.
  
  
  METHODS
  An investigator-initiated study was performed in a single maternity hospital in Helsinki, Finland.
  
  
  METHODS
  S-25-OHD, calcium homeostasis, and skeletal characteristics were evaluated with peripheral quantitative computed tomography at age 3 months.
  
  
  RESULTS
  Baseline S-25-OHD was similar in all three groups (median, 53 nmol/liter). At 3 months, the mean S-25-OHD values were 88, 124, and 153 nmol/liter, and the minimum values were 46, 57, and 86 nmol/liter in the groups receiving 10, 30, and 40 μg (ANOVA; P < 0.001). No hypercalcemia occurred; plasma calcium, serum PTH, and urine calcium excretion was similar between the groups. Peripheral quantitative computed tomography showed a trend toward larger tibial total bone and cortical bone area with higher vitamin D doses.
  
  
  CONCLUSIONS
  Vitamin D3 supplementation with up to 40 μg/d from age 2 wk to 3 months was safe and caused no hypercalcemia or hypercalciuria. The 40-μg dose maintained S-25-OHD above 80 nmol/liter in all infants. More extensive and longer intervention studies are necessary to assess long-term effects.
authors.affiliation: Pediatric Endocrinology and Metabolic Bone Diseases, Children's Hospital, Helsinki University Central Hospital and University of Helsinki, P.O. Box 281, FIN-00029 HUS, Helsinki, Finland.
authors.forename: Elisa
authors.initials: E
authors.lastname: Holmlund-Suila
authors.forename: Heli
authors.initials: H
authors.lastname: Viljakainen
authors.forename: Timo
authors.initials: T
authors.lastname: Hytinantti
authors.forename: Christel
authors.initials: C
authors.lastname: Lamberg-Allardt
authors.forename: Sture
authors.initials: S
authors.lastname: Andersson
authors.forename: Outi
authors.initials: O
authors.lastname: Mäkitie
mesh_terms: D002762:Cholecalciferol / Q000008:administration & dosage*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005387:Finland; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D016896:Treatment Outcome; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000032:analysis / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood; D014815:Vitamins / Q000008:administration & dosage*
chemical_list: D014815:Vitamins; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D