title: [The influence of bariatric surgery on calcium homeostasis and biochemical markers of bone turnover in patients with morbid obesity].
abstract: BACKGROUND
  Obese patients may have abnormal calcium homeostasis because of unbalanced diet and decreased sun exposure. Bariatric surgery itself may lead to disturbances in calcium homeostasis (and in consequence changes in bone mass) or increase preexisting metabolic derangements. The aim of the study was: 1. To assess calcium homeostasis and biochemical markers of bone turnover in patients with morbid obesity. 2. To determine the impact of bariatric surgery on parameters mentioned above. 3. To establish recommendations for supplementation with calcium and vitamin D in morbidly obese patients after bariatric surgery.
  
  
  METHODS
  Serum calcium, parathormone (PTH), vitamin D (25(OH)D), biochemical markers of bone turnover (beta-CrossLaps as a marker of bone resorption and osteocalcin as a marker of bone formation) and urine calcium as well as fat mass, lean mass and bone mineral content (by DXA) were measured before bariatric surgery of the stomach (VBG or GBP) in 57 morbidly obese patients (48 women, 9 men; mean age 35.9 y). The same procedures were repeated six months after operation in 28 of them (24 women, 4 men). Daily calcium intake was also determined based on food questionnaire.
  
  
  RESULTS
  Biochemical findings in the group of patients before bariatric surgery were as follows: serum calcium, beta-CrossLaps and urine calcium were within normal range, PTH concentration was increased to 81.0 pg/ml and 25(OH)D as well as osteocalcin concentration decreased (4.9 ng/ml and 13.6 ng/ml, respectively). Six months after bariatric surgery there was no change in serum and urine calcium, PTH concentration decreased to normal level (46.8 pg/ml), 25(OH)D concentration increased to 6.5 ng/ml (not significant) and still remained below normal range. Markers of bone turnover--both resorption and formation--increased (beta-CrossLaps over normal range to 0.594 ng/ml, osteocalcin to normal range 26.8 ng/ml). Daily calcium intake was below RDA before and after bariatric procedure.
  
  
  CONCLUSIONS
  1. Patients with morbid obesity have secondary hyperparathyroidism and deficiency of vitamin D. 2. Abrupt weight loss after bariatric surgery is accompanied by the regression of secondary hyperparathyroidism, decrease of the deficiency of vitamin D and increase in bone turnover. 3. Supplementation with vitamin D and calcium is recommended for patients with morbid obesity after bariatric surgery.
authors.affiliation: Klinika Medycyny Rodzinnej i Chorób Wewnetrznych, Centrum Medycznego Kształcenia Podyplomowego, Warszawa. eczerwinska@szpital-orlowskiego.pl
authors.forename: Ewa
authors.initials: E
authors.lastname: Czerwińska
authors.forename: Ewa
authors.initials: E
authors.lastname: Marcinowska-Suchowierska
authors.forename: Magdalena
authors.initials: M
authors.lastname: Walicka
authors.forename: Wojciech
authors.initials: W
authors.lastname: Lisik
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Wierzbicki
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D016723:Bone Remodeling; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002136:Calcium, Dietary; D005260:Female; D015390:Gastric Bypass; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000378:metabolism* / Q000601:surgery*; D015675:Osteocalcin / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood; D014807:Vitamin D / Q000097:blood; D015431:Weight Loss
chemical_list: D015415:Biomarkers; D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D015675:Osteocalcin; D014807:Vitamin D; D002118:Calcium