title: Safety of vitamin D3 in adults with multiple sclerosis.
abstract: BACKGROUND
  Vitamin D3 may have therapeutic potential in several diseases, including multiple sclerosis. High doses of vitamin D(3) may be required for therapeutic efficacy, and yet tolerability--in the present context, defined as the serum concentration of 25-hydroxyvitamin D [25(OH)D] that does not cause hypercalcemia--remains poorly characterized.
  
  
  OBJECTIVE
  The objective of the study was to characterize the calcemic response to specific serum 25(OH)D concentrations.
  
  
  METHODS
  In a 28-wk protocol, 12 patients in an active phase of multiple sclerosis were given 1200 mg elemental Ca/d along with progressively increasing doses of vitamin D3: from 700 to 7000 microg/wk (from 28 000 to 280 000 IU/wk).
  
  
  RESULTS
  Mean (+/- SD) serum concentrations of 25(OH)D initially were 78 +/- 35 nmol/L and rose to 386 +/- 157 nmol/L (P < 0.001). Serum calcium concentrations and the urinary ratio of calcium to creatinine neither increased in mean values nor exceeded reference values for any participant (2.1-2.6 mmol/L and <1.0, respectively). Liver enzymes, serum creatinine, electrolytes, serum protein, and parathyroid hormone did not change according to Bonferroni repeated-measures statistics, although parathyroid hormone did decline significantly according to the paired t test. Disease progression and activity were not affected, but the number of gadolinium-enhancing lesions per patient (assessed with a nuclear magnetic brain scan) decreased from the initial mean of 1.75 to the end-of-study mean of 0.83 (P = 0.03).
  
  
  CONCLUSIONS
  Patients' serum 25(OH)D concentrations reached twice the top of the physiologic range without eliciting hypercalcemia or hypercalciuria. The data support the feasibility of pharmacologic doses of vitamin D3 for clinical research, and they provide objective evidence that vitamin D intake beyond the current upper limit is safe by a large margin.
authors.affiliation: Department of Nutritional Sciences, University of Toronto, Toronto, Canada. samantha.kimball@utoronto.ca
authors.forename: Samantha M
authors.initials: SM
authors.lastname: Kimball
authors.forename: Melanie R
authors.initials: MR
authors.lastname: Ursell
authors.forename: Paul
authors.initials: P
authors.lastname: O'Connor
authors.forename: Reinhold
authors.initials: R
authors.lastname: Vieth
mesh_terms: D000328:Adult; D050071:Bone Density Conservation Agents / Q000009:adverse effects / Q000627:therapeutic use; D002118:Calcium / Q000097:blood / Q000652:urine; D002762:Cholecalciferol / Q000009:adverse effects* / Q000627:therapeutic use*; D003404:Creatinine / Q000097:blood / Q000652:urine; D019587:Dietary Supplements; D018450:Disease Progression; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000097:blood; D008099:Liver / Q000201:enzymology; D008279:Magnetic Resonance Imaging; D008297:Male; D009103:Multiple Sclerosis / Q000097:blood* / Q000188:drug therapy; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000097:blood* / Q000188:drug therapy; D019055:No-Observed-Adverse-Effect Level; D010281:Parathyroid Hormone / Q000097:blood; D012016:Reference Values; D012307:Risk Factors; D012449:Safety; D013997:Time Factors; D016896:Treatment Outcome; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000517:prevention & control