title: Vitamin D and hyperparathyroidism in obesity.
abstract: BACKGROUND
  Low vitamin D status and hyperparathyroidism occur in obesity and may be involved in pathogenesis of obesity-associated comorbid conditions.
  
  
  OBJECTIVE
  Our aims were to determine in obesity whether there was vitamin D insufficiency, assessed by serum 25-hydroxyvitamin D (s25D) and serum PTH (sPTH) and whether it related to comorbid conditions.
  
  
  METHODS
  We conducted a case-control study of 48 women having bariatric surgery and 50 healthy women frequency matched for race, age, year, and season of study. Height, weight, s25D, sPTH, serum 1,25-dihydroxyvitamin D (s1,25D), serum bone alkaline phosphatase, serum cross-linked N-telopeptides of type 1 collagen, and serum calcium, phosphate, creatinine, glucose, and insulin were measured, and comorbid conditions were documented from patient files.
  
  
  RESULTS
  Weight (140 vs. 76 kg, P < 0.001), sPTH (44.4 vs. 25.6 pg/ml, P < 0.001), s1,25D (39 vs. 24 pg/ml, P < 0.001), serum bone alkaline phosphatase (19 vs. 12 ng/ml, P < 0.001), serum cross-linked N-telopeptides of type 1 collagen (9.6 vs. 7.9 nm bone collagen equivalents, P = 0.007), serum phosphate (3.45 vs. 3.24 mg/dl, P = 0.043), and serum creatinine (1.05 vs. 0.87 mg/dl, P < 0.001) were higher, and s25D (16 vs. 23 ng/ml, P <.001) was lower in bariatric-surgery women than control women. s25D was lower in bariatric-surgery women than controls in summer (17 vs. 26 ng/ml, P < 0.0001) but not winter (15 vs. 18 ng/ml, P > 0.2). Multiple regression analysis demonstrated that weight predicted s25D (P < 0.001) and sPTH (P = 0.001), but s25D did not predict sPTH or the presence of comorbid conditions except for osteoarthritis.
  
  
  CONCLUSIONS
  Women having bariatric surgery had lower s25D and higher sPTH. The major determinant of s25D and sPTH was weight. Hyperparathyroidism in obesity did not indicate vitamin D insufficiency. Low s25D was not associated with comorbid conditions, apart from osteoarthritis.
authors.affiliation: Division of Endocrinology and Metabolism, Indiana University School of Medicine, Indianapolis, Indiana 46202-5111, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Grethen
authors.forename: Ronald
authors.initials: R
authors.lastname: McClintock
authors.forename: Christine E
authors.initials: CE
authors.lastname: Gupta
authors.forename: RoseMarie
authors.initials: R
authors.lastname: Jones
authors.forename: Brenda M
authors.initials: BM
authors.lastname: Cacucci
authors.forename: David
authors.initials: D
authors.lastname: Diaz
authors.forename: Angie D
authors.initials: AD
authors.lastname: Fulford
authors.forename: Susan M
authors.initials: SM
authors.lastname: Perkins
authors.forename: Robert V
authors.initials: RV
authors.lastname: Considine
authors.forename: Munro
authors.initials: M
authors.lastname: Peacock
mesh_terms: D000328:Adult; D000367:Age Factors; D000713:Anastomosis, Roux-en-Y; D000886:Anthropometry; D001835:Body Weight; D016022:Case-Control Studies; D003627:Data Interpretation, Statistical; D004100:Dihydroxycholecalciferols / Q000097:blood; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000209:etiology*; D008875:Middle Aged; D009752:Nutritional Status; D009765:Obesity / Q000150:complications*; D010281:Parathyroid Hormone / Q000097:blood; D012044:Regression Analysis; D014808:Vitamin D Deficiency / Q000209:etiology*
chemical_list: D004100:Dihydroxycholecalciferols; D010281:Parathyroid Hormone