title: A randomized, controlled lower leg growth study of vitamin D supplementation to healthy children during the winter season.
abstract: BACKGROUND
  The deceleration of longitudinal growth in children during winter occurs simultaneously with a decrease in the number of daylight hours and a reduction in vitamin D status. Due to worries about deleterious effects on bone of a relative insufficiency, vitamin D supplementation to healthy children has been suggested.
  
  
  OBJECTIVE
  To see whether supplementation of vitamin D to healthy children during winter affects seasonal growth.
  
  
  METHODS
  Twelve girls and eight boys aged 6.2-13.7 (mean 9.8) years, all healthy, were enrolled in a double-blind, randomized, placebo-controlled cross-over study with two 4-week treatment periods and 2-week run-in and wash-out periods. Vitamin D(3) 600 IU was given in one tablet ABCDin daily. Knemometry of the right lower leg was performed on the first and last day of each period.
  
  
  RESULTS
  Lower leg growth rates (mean +/- SEM) during placebo and vitamin D(3) administration were identical: 0.28 +/- 0.04 mm per week (p = 0.94, t = 0.1, 95% CI: - 0.12-0.13 mm per week).
  
  
  CONCLUSIONS
  Supplementation with vitamin D(3) 600 IU day(-1) to healthy children during winter may not improve seasonal growth. Therefore, supplementation may not be recommended on the grounds of concerns about growth; however firm conclusions await randomized long-term studies.
authors.affiliation: Children's Clinic Randers, Randers, Denmark. ajs@dadlnet.dk
authors.forename: A J
authors.initials: AJ
authors.lastname: Schou
authors.forename: C
authors.initials: C
authors.lastname: Heuck
authors.forename: O D
authors.initials: OD
authors.lastname: Wolthers
mesh_terms: D000293:Adolescent; D002648:Child; D018592:Cross-Over Studies; D003718:Denmark; D019587:Dietary Supplements; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D005360:Fibula / Q000187:drug effects / Q000254:growth & development*; D006801:Humans; D008297:Male; D012621:Seasons; D013472:Sunlight; D013977:Tibia / Q000187:drug effects / Q000254:growth & development*; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood
chemical_list: D014807:Vitamin D