title: Calcium and vitamin D supplementation after gastric bypass should be individualized to improve or avoid hyperparathyroidism.
abstract: BACKGROUND
  Precise calcium (Ca) and vitamin D intestinal absorption after gastric bypass (GB) remains unknown. We evaluated the effect of receiving or not Ca and vitamin D supplementation on Ca, PTH, and vitamin D axis in patients undergoing GB.
  
  
  METHODS
  Two hundred twenty-two patients were evaluated prior to GB and at 1 year. Baseline characteristics were registered, and bone metabolism markers were determined before surgery and at 12 months. After surgery, oral calcium carbonate (1,200 mg/daily) and vitamin D3 (800 IU) were prescribed with PTH >70 pg/ml.
  
  
  RESULTS
  In the whole group, before surgery and at 1 year, 36 and 30% had hyperparathyroidism (HPT), respectively. Baseline vitamin D deficiency (<50 nmol/L) was observed in 52% with insufficiency (50-75 nmol/L) in 28%. Linear regression analysis showed a significant positive relationship between PTH and excess body weight (EBW) (r 0.190) with a significant negative relationship between PTH and 25 (OH) D (r-0.243). Only EBW was independently associated with HPT on multivariate logistic regression. PTH and 25 (OH) D significantly improved at 1 year with Ca supplementation, but HPT continued in 35 and in 71%, 25 (OH) D was <75 nmol/L. 25 (OH) D only increased 11.5 nmol/L with supplementation. Without Ca supplementation, both PTH and 25 (OH) D increased. HPT developed in 15% with 25 (OH) D < 75 nmol/L in 66%.
  
  
  CONCLUSIONS
  Ca and vitamin D supplementation after GB should be universal and individualized to overcome mal-absorption and improve previous 25 (OH) D deficiency.
authors.affiliation: Obesity Unit, Hospital Clínic i Universitari, Villarroel 170, 08036, Barcelona, Spain. lflores@clinic.ub.es
authors.forename: Lilliam
authors.initials: L
authors.lastname: Flores
authors.forename: M Jesús Martínez
authors.initials: MJ
authors.lastname: Osaba
authors.forename: Alba
authors.initials: A
authors.lastname: Andreu
authors.forename: Violeta
authors.initials: V
authors.lastname: Moizé
authors.forename: Lucía
authors.initials: L
authors.lastname: Rodríguez
authors.forename: Josep
authors.initials: J
authors.lastname: Vidal
mesh_terms: D000328:Adult; D000863:Antacids / Q000627:therapeutic use; D002118:Calcium / Q000097:blood / Q000627:therapeutic use; D002119:Calcium Carbonate / Q000627:therapeutic use; D019963:Clinical Chemistry Tests; D019587:Dietary Supplements; D005260:Female; D015390:Gastric Bypass / Q000009:adverse effects / Q000379:methods; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood / Q000209:etiology / Q000517:prevention & control*; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D016896:Treatment Outcome; D014807:Vitamin D / Q000097:blood / Q000627:therapeutic use; D014808:Vitamin D Deficiency / Q000517:prevention & control*; D014815:Vitamins / Q000097:blood / Q000627:therapeutic use
chemical_list: D000863:Antacids; D014815:Vitamins; D014807:Vitamin D; D002119:Calcium Carbonate; D002118:Calcium