title: Treatment with 50,000 IU vitamin D₂ every other week and effect on serum 25-hydroxyvitamin D₂, 25-hydroxyvitamin D₃, and total 25-hydroxyvitamin D in a clinical setting.
abstract: OBJECTIVE
  To examine the effect of 50,000 IU-vitamin D₂ supplementation in a clinical setting on serum total 25-hydroxyvitamin D (25[OH]D), 25-hydroxyvitamin D₂ (25[OH]D₂), and 25-hydroxyvitamin D3 (25[OH]D₃).
  
  
  METHODS
  This retrospective cohort study was performed in an urban tertiary referral hospital in Boston, Massachusetts. Patients who had been prescribed 50,000 IU vitamin D₂ repletion and maintenance programs were identified through a search of our electronic medical record. Baseline and follow-up total serum 25(OH)D, 25(OH)D₂, and 25(OH)D₃ levels were compared.
  
  
  RESULTS
  We examined the medical records of 48 patients who had been prescribed 50,000 IU vitamin D₂ in our clinic. Mean ± standard deviation baseline total 25(OH)D was 31.0 ± 10.6 ng/mL and rose to 48.3 ± 13.4 ng/mL after treatment (P<.001). 25(OH)D₂ increased from 4.2 ± 4.3 ng/mL to 34.6 ± 12.3 ng/mL after treatment (P<.001), for an average of 158 days (range, 35-735 days). Serum 25(OH)D₃ decreased from 26.8 ± 10.8 ng/mL to 13.7 ± 7.9 ng/mL (P<.001).
  
  
  CONCLUSIONS
  Fifty thousand IU vitamin D₂ repletion and maintenance therapy substantially increases total 25(OH)D and 25(OH)D₂ despite a decrease in serum 25(OH)D₃. This treatment program is an appropriate and effective strategy to treat and prevent vitamin D deficiency.
authors.affiliation: Section of Endocrinology and Diabetes, Maine Medical Center, Portland, Maine, USA.
authors.forename: Emily T W
authors.initials: ET
authors.lastname: Demetriou
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Travison
authors.forename: Michael F
authors.initials: MF
authors.lastname: Holick
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood*; D001900:Boston; D002112:Calcifediol / Q000097:blood*; D015331:Cohort Studies; D019587:Dietary Supplements / Q000009:adverse effects; D057286:Electronic Health Records; D004872:Ergocalciferols / Q000008:administration & dosage* / Q000009:adverse effects / Q000378:metabolism; D005500:Follow-Up Studies; D006801:Humans; D007700:Kinetics; D012189:Retrospective Studies; D055502:Secondary Prevention; D014504:Urban Health; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000178:diet therapy* / Q000517:prevention & control
chemical_list: D004872:Ergocalciferols; D014807:Vitamin D; D015652:25-Hydroxyvitamin D 2; C104450:25-hydroxyvitamin D; D002112:Calcifediol