title: No significant effect on bone mineral density by high doses of vitamin D3 given to overweight subjects for one year.
abstract: BACKGROUND
  In meta-analyses supplementation with vitamin D appears to reduce incidence of fractures, and in cross-sectional studies there is a positive association between serum 25-hydroxyvitamin D (25(OH)D) levels and bone mineral density (BMD). However, the effect of supplementation with high doses of vitamin D on BMD is more uncertain and could in theory have both positive and negative effects.
  
  
  METHODS
  The study was a one year, double blind placebo-controlled intervention trial performed at the University Hospital of North Norway. 421 subjects, 21 - 70 years old, were included and 312 completed the study. The subjects were randomized to vitamin D3 40.000 IU per week (DD group), vitamin D3 20.000 IU per week (DP group), or placebo (PP group). All subjects were given 500 mg calcium daily. Serum 25(OH)D, osteoprotegrin (OPG), receptoractivator of nuclear factor-kappaB ligand (RANKL), and BMD at the lumbar spine and the hip were measured before and at the end of the study.
  
  
  RESULTS
  At baseline the mean serum 25(OH)D levels were 58 nmol/L (all subjects) and increased to 141 and 100 nmol/L in the DD and DP groups, respectively. After one year, no significant differences were found between the three groups regarding change in BMD, serum OPG or RANKL.
  
  
  CONCLUSIONS
  Supplementation with high doses of vitamin D for one year does not appear to have a negative effect on BMD in healthy subjects. In order to disclose a positive effect, subjects with low BMD and/or low serum 25(OH)D levels need to be studied.
  
  
  BACKGROUND
  The trial was registered at ClinicalTrials.gov (NCT00243256).
authors.affiliation: Institute of Clinical Medicine, University of Tromsø, University Hospital of North Norway, Tromsø, Norway. rolf.jorde@unn.no
authors.forename: Rolf
authors.initials: R
authors.lastname: Jorde
authors.forename: Monica
authors.initials: M
authors.lastname: Sneve
authors.forename: Peter A
authors.initials: PA
authors.lastname: Torjesen
authors.forename: Yngve
authors.initials: Y
authors.lastname: Figenschau
authors.forename: John-Bjarne
authors.initials: JB
authors.lastname: Hansen
authors.forename: Guri
authors.initials: G
authors.lastname: Grimnes
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015519:Bone Density / Q000187:drug effects*; D050071:Bone Density Conservation Agents / Q000008:administration & dosage* / Q000097:blood; D002762:Cholecalciferol / Q000008:administration & dosage* / Q000097:blood; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway; D050177:Overweight / Q000097:blood*; D053245:RANK Ligand / Q000097:blood / Q000187:drug effects; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D055815:Young Adult
chemical_list: D015415:Biomarkers; D050071:Bone Density Conservation Agents; D053245:RANK Ligand; D014807:Vitamin D; D002762:Cholecalciferol; C104450:25-hydroxyvitamin D