title: Prevalence of vitamin D insufficiency and deficiency in morbidly obese patients: a comparison with non-obese controls.
abstract: BACKGROUND
  Vitamin D deficiency is common in patients after bariatric surgery. However, obesity itself has also been associated with decreased vitamin D. The prevalence of vitamin D deficiency in obese persons has not previously been compared to non-obese controls when controlling for factors that could affect vitamin D status.
  
  
  METHODS
  We evaluated 25 hydroxy vitamin D, iPTH, calcium, albumin, and creatinine in 41 patients undergoing Roux-en-Y gastric bypass. We then compared them to healthy non-obese controls matched for age, sex, race/ethnicity, and season of vitamin D measurement.
  
  
  RESULTS
  Ninety percent of the pre-bariatric surgery patients had 25-OH-D levels <75 nmol/l, and 61% had 25-OH-D levels <50 nmol/l versus 32 and 12% in controls, respectively. Additionally, 49% of the pre-bariatric surgery patients had secondary hyperparathyroidism versus 2% of controls. These differences persisted after controlling for sunlight exposure and dietary intake of calcium and vitamin D. Mean calcium, corrected for albumin, and creatinine were not significantly different between the groups, but mean albumin levels were significantly lower among surgery patients.
  
  
  CONCLUSIONS
  Vitamin D deficiency is common in obese patients at the time of bariatric surgery and is also accompanied by secondary hyperparathyroidism approximately half the time. These findings suggest that vitamin D deficiency after bariatric surgery is multifactorial and in part caused by preoperative vitamin D deficiency rather than postoperative malabsorption alone. In this study, increased vitamin D deficiency in obese persons cannot be explained by a difference in calcium/vitamin D intake or sunlight exposure.
authors.affiliation: Department of Internal Medicine, Section of Diabetes, Endocrinology, and Metabolism, University of Nebraska Medical Center, Omaha, NE 68198-3020, USA. wgoldner@unmc.edu
authors.forename: Whitney S
authors.initials: WS
authors.lastname: Goldner
authors.forename: Julie A
authors.initials: JA
authors.lastname: Stoner
authors.forename: Jon
authors.initials: J
authors.lastname: Thompson
authors.forename: Karen
authors.initials: K
authors.lastname: Taylor
authors.forename: Luann
authors.initials: L
authors.lastname: Larson
authors.forename: Judi
authors.initials: J
authors.lastname: Erickson
authors.forename: Corrigan
authors.initials: C
authors.lastname: McBride
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000150:complications*; D010865:Pilot Projects; D015995:Prevalence; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology* / Q000209:etiology
chemical_list: D014807:Vitamin D