title: Markers of Bone Metabolism in Obese Individuals Undergoing Laparoscopic Sleeve Gastrectomy.
abstract: BACKGROUND
  Besides its advantages, bariatric surgery implicates a risk of nutritional deficiencies, which might result in impaired bone metabolism. We assessed the effect of laparoscopic sleeve gastrectomy (LSG) on blood markers of bone metabolism in obese patients during a 3-year observation period.
  
  
  METHODS
  In 39 obese patients (29 women, 10 men, mean BMI 51.8 ± 6.8 kg/m(2)) undergoing LSG, we measured blood concentrations of 25-hydroxyvitamin D (25(OH)D), calcium, parathyroid hormone (PTH), bone alkaline phosphatase (BAP), and N-telopeptides crosslinks (NTx) before LSG and up to 3 years postoperatively. Vitamin D and calcium supplementations were recorded.
  
  
  RESULTS
  LSG caused an excess weight loss (EWL) of 54 ± 20 % after 3 years. Before surgery, we found decreased levels of 25(OH)D and calcium in 80 and 5 % of the subjects, respectively, while increased levels of PTH, BAP, and NTx were found in 39, 28, and 21 %, respectively. Mean levels of NTx and the prevalence of elevated levels of NTx increased within 2 years (p < 0.001 and p < 0.01). Neither mean blood concentrations of 25(OH)D, calcium, PTH, and BAP nor relative prevalence of deficiencies regarding these markers changed during the study period. The supplementation rates of calcium and vitamin D increased postoperatively.
  
  
  CONCLUSIONS
  Morbid obesity is associated with pronounced changes of markers of bone metabolism; LSG did neither aggravate nor ameliorate vitamin D metabolism within a 3-year time period, but led to increased bone resorption 2 years postoperatively. Routine supplementation of calcium and vitamin D is not likely sufficient to compensate the obesity-associated deficiencies in bone metabolism.
authors.affiliation: Department of Nutritional Medicine, University of Hohenheim, Fruwirthstraße 12, 70593, Stuttgart, Germany, asja.schollenberger@uni-hohenheim.de.
authors.forename: Asja E
authors.initials: AE
authors.lastname: Schollenberger
authors.forename: Jaana M
authors.initials: JM
authors.lastname: Heinze
authors.forename: Tobias
authors.initials: T
authors.lastname: Meile
authors.forename: Andreas
authors.initials: A
authors.lastname: Peter
authors.forename: Alfred
authors.initials: A
authors.lastname: Königsrainer
authors.forename: Stephan C
authors.initials: SC
authors.lastname: Bischoff
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001842:Bone and Bones / Q000378:metabolism*; D002118:Calcium / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D005743:Gastrectomy / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood* / Q000378:metabolism / Q000601:surgery*; D010281:Parathyroid Hormone / Q000097:blood; D011184:Postoperative Period; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D015431:Weight Loss
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D000469:Alkaline Phosphatase; D002118:Calcium