title: Changes in Hematology and Calcium Metabolism After Gastric Bypass Surgery--a 2-Year Follow-Up Study.
abstract: BACKGROUND
  Concerns regarding nutritional deficiencies have recently emerged after Roux-en-Y gastric bypass (RYGB).
  
  
  METHODS
  A total of 835 subjects underwent RYGB, age 43.3 years, body mass index (BMI) 47.2 kg/m(2). Hematological and calcium metabolic variables were measured before, 6, 12, and 24 months after surgery. Daily supplement of 800 mg calcium, 800 U vitamin D, a multivitamin, and a vitamin B12 injection (1 mg) every third month was recommended. In subjects with low ferritin and decreasing hemoglobin levels, oral, or intravenous iron was administered.
  
  
  RESULTS
  Hemoglobin concentration decreased from before surgery to month 24 for both men (9.3 ± 0.05 vs. 8.3 ± 0.08 mmol/L, p < 0.001) and women (8.4 ± 0.03 vs. 7.7 ± 0.06 mmol/L, p < 0.001). At 24 months, anemia was present in 25.8 % of women and 22.1 % of men. Predictors of anemia in both sexes were baseline hemoglobin (p < 0.001), excessive weight loss in men, and younger age in women (p < 0.001). Plasma ferritin levels decreased in both sexes (p < 0.01), whereas concentrations of folic acid and vitamin B12 increased from before surgery to 24 months after surgery (p < 0.001). Vitamin D increased from baseline to month 24 in both sexes (p < 0.01). In women, PTH increased from baseline to month 24 (p < 0.05) with no changes in calcium or magnesium.
  
  
  CONCLUSIONS
  Supplementation of calcium and vitamin D was sufficient. Iron substitution did not prevent anemia, which especially affected premenopausal women. More attention should be given to iron substitution after RYGB.
authors.affiliation: Department of Internal Medicine, Køge Hospital, Lykkebækvej 1, 4600, Køge, Denmark, dow@regionsjaelland.dk.
authors.forename: Dorte
authors.initials: D
authors.lastname: Worm
authors.forename: Sten
authors.initials: S
authors.lastname: Madsbad
authors.forename: Viggo B
authors.initials: VB
authors.lastname: Kristiansen
authors.forename: Lars
authors.initials: L
authors.lastname: Naver
authors.forename: Dorte Lindqvist
authors.initials: DL
authors.lastname: Hansen
mesh_terms: D000328:Adult; D000740:Anemia / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology; D002118:Calcium / Q000097:blood / Q000378:metabolism*; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass; D006801:Humans; D008297:Male; D044342:Malnutrition / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D008875:Middle Aged; D009767:Obesity, Morbid / Q000097:blood / Q000503:physiopathology / Q000601:surgery*
chemical_list: D002118:Calcium