title: Finding the optimal dose of vitamin D following Roux-en-Y gastric bypass: a prospective, randomized pilot clinical trial.
abstract: BACKGROUND
  Vitamin D deficiency is common following bariatric surgery and is due to a combination of baseline deficiency and postoperative malabsorption. There are few prospective studies evaluating the appropriate dose of vitamin D to prevent and treat vitamin D deficiency following bariatric surgery.
  
  
  METHODS
  We evaluated three doses of vitamin D3 (800, 2,000, and 5,000 IU/day) in a prospective, randomized pilot trial of 45 patients undergoing Roux-en-Y gastric bypass. Serum 25 hydroxy Vitamin D (25OHD), intact PTH (iPTH), calcium, and urine calcium/creatinine ratios were measured at 6, 12, and 24 months postoperatively. Due to a high dropout rate at 24 months, we focus on the 12-month data.
  
  
  RESULTS
  At 12 months, the 800-, 2,000-, and 5,000-IU groups had a mean +/- SD increase in 25OHD of 27.5 +/- 40.0, 60.2 +/- 37.4, and 66.1 +/- 42.2 nmol/L, respectively (p = 0.09) with a maximum increase in each group of 87.4, 114.8, and 129.8 nmol/L. Forty-four percent, 78%, and 70% achieved 25OHD levels >or=75 nmol/L (p = 0.38). Results for the 6- and 24-month time points were similar to the 12-month results. Mean weight loss at 24 months of the study was not different among groups (p = 0.52). Serum calcium did not change significantly, and there were no cases of hypercalcemia or sustained hypercalciuria.
  
  
  CONCLUSIONS
  Higher doses of vitamin D supplementation trend towards higher levels of 25OHD. Vitamin D replacement as high as 5,000 IU /day is safe and necessary in many patients to treat vitamin D deficiency following Roux-en-Y gastric bypass yet is still suboptimal in others.
authors.affiliation: Section of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, 68198-3020, USA. wgoldner@unmc.edu.
authors.forename: Whitney S
authors.initials: WS
authors.lastname: Goldner
authors.affiliation: Department of Biostatistics and Epidemiology, College of Public Health, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Stoner
authors.affiliation: Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Lyden
authors.affiliation: Department of Surgery, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Jon
authors.initials: J
authors.lastname: Thompson
authors.affiliation: Department of Surgery, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Taylor
authors.affiliation: Clinical Research Center, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Luann
authors.initials: L
authors.lastname: Larson
authors.affiliation: Section of Diabetes, Endocrinology, and Metabolism, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, 68198-3020, USA.
authors.forename: Judi
authors.initials: J
authors.lastname: Erickson
authors.affiliation: Department of Surgery, University of Nebraska Medical Center, Omaha, NE, USA.
authors.forename: Corrigan
authors.initials: C
authors.lastname: McBride
mesh_terms: D000328:Adult; D002118:Calcium / Q000097:blood / Q000652:urine; D003404:Creatinine / Q000652:urine; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000601:surgery; D010281:Parathyroid Hormone / Q000097:blood; D010865:Pilot Projects; D011182:Postoperative Care / Q000379:methods; D011446:Prospective Studies; D016896:Treatment Outcome; D014807:Vitamin D / Q000008:administration & dosage* / Q000097:blood; D014808:Vitamin D Deficiency / Q000209:etiology* / Q000517:prevention & control*; D014815:Vitamins / Q000008:administration & dosage*; D015431:Weight Loss
chemical_list: D010281:Parathyroid Hormone; D014815:Vitamins; D014807:Vitamin D; D003404:Creatinine; D002118:Calcium
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