title: Optimization of Vitamin D Status After Roux-en-Y Gastric Bypass Surgery in Obese Patients Living in Northern Climate.
abstract: BACKGROUND
  Patients who undergo bariatric surgery are at risk for micronutrient deficiencies. The aims of this study were to determine the prevalence and predictors of vitamin D deficiency in obese patients residing in the northern climate, and to evaluate the effectiveness of a daily maintenance dose of vitamin D 2000 IU in preventing hypovitaminosis D within 1 year after bariatric surgery.
  
  
  METHODS
  A cohort study involving adult patients undergoing RYGB was conducted. Longitudinal changes in serum vitamin D concentrations and clinical parameters were measured and collected.
  
  
  RESULTS
  Data from 134 recipients of RYGB were analyzed. Hypovitaminosis D was identified in 86 patients (64 %), and was significantly affected by seasonal change and the number of comorbidities. Follow-up data were available in 60 patients. Vitamin D sufficiency was achieved in 62.5 % of those patients with baseline vitamin D insufficiency. A dose-response relationship of vitamin D intake was observed, with the most significant increase in 25(OH)D associated with daily vitamin D intakes ≥ 2000 IU.
  
  
  CONCLUSIONS
  The prevalence of hypovitaminosis D before RYGB was comparable to patients living in the non-northern climate. Daily vitamin D intake meeting at least 2000 IU is associated with greater improvement in serum vitamin D concentration.
authors.affiliation: Department of Pharmacy, School of Pharmacy, University of Washington, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195, USA. neander@u.washington.edu.|Graduate Program in Nutritional Sciences, School of Public Health, Seattle, WA, USA. neander@u.washington.edu.
authors.forename: Lingtak-Neander
authors.initials: LN
authors.lastname: Chan
authors.affiliation: Graduate Program in Nutritional Sciences, School of Public Health, Seattle, WA, USA.
authors.forename: Charlotte H
authors.initials: CH
authors.lastname: Neilson
authors.affiliation: Graduate Program in Nutritional Sciences, School of Public Health, Seattle, WA, USA.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Kirk
authors.affiliation: Department of Pharmacy, School of Pharmacy, University of Washington, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195, USA.|Graduate Program in Nutritional Sciences, School of Public Health, Seattle, WA, USA.|Department of Nutritional Services, University of Washington Medical Center, Seattle, WA, USA.
authors.forename: Tiana F
authors.initials: TF
authors.lastname: Colovos
authors.affiliation: Department of Pharmacy, School of Pharmacy, University of Washington, 1959 NE Pacific Street, Box 357630, Seattle, WA, 98195, USA.|Graduate Program in Nutritional Sciences, School of Public Health, Seattle, WA, USA.|Department of Nutritional Services, University of Washington Medical Center, Seattle, WA, USA.
authors.forename: Diane R
authors.initials: DR
authors.lastname: Javelli
authors.affiliation: Department of Surgery, School of Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Saurabh
authors.initials: S
authors.lastname: Khandelwal
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000009:adverse effects / Q000706:statistics & numerical data; D002980:Climate; D003080:Cold Temperature; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000453:epidemiology / Q000601:surgery*; D015995:Prevalence; D012189:Retrospective Studies; D012621:Seasons; D014807:Vitamin D / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology; D055815:Young Adult
chemical_list: D014807:Vitamin D
keywords: Bariatric surgery; Northern climate; Roux-en-Y gastric bypass; Vitamin D