title: Vitamin D status 10 years after primary gastric bypass: gravely high prevalence of hypovitaminosis D and raised PTH levels.
abstract: BACKGROUND
  The primary aim of this study was to evaluate the prevalence of vitamin D deficiency and secondary hyperparathyroidism after Roux-en-Y gastric bypass. Secondly, we have tried to assess predictors for vitamin D deficiency.
  
  
  METHODS
  Five hundred thirty-seven patients who underwent primary Roux-en-Y gastric bypass surgery between 1993 and 2003 at the Örebro University Hospital and Uppsala University Hospital were eligible for the study. Patients were asked to provide a blood sample between November 2009 and June 2010 and to complete a questionnaire about their postoperative health status. Serum values of 25-OH vitamin D, parathyroid hormone (PTH), alkaline phosphatase (ALP) and calcium were determined.
  
  
  RESULTS
  Follow-up was completed in 293 patients, of which 83 % were female, with an age of 49 ± 9.9 years after a median time of 11 ± 2.8 years. Vitamin D, PTH and albumin-corrected calcium values were 42 ± 20.4 nmol/L, 89.1 ± 52.7 ng/L and 2.3 ± 0.1 mmol/L, respectively. Of all patients, 65 % were vitamin D deficient, i.e. 25-OH vitamin D <50 nmol/L, and 69 % had PTH above the upper normal reference range, i.e. >73 ng/L. Vitamin D was inversely correlated with PTH levels (p < 0.001) and positively correlated with calcium (p = 0.016). Vitamin D did not correlate with ALP. The only factor found to predict vitamin D deficiency was high preoperative body mass index (BMI) (p = 0.008), whereas gender, age, time after surgery and BMI at follow-up did not.
  
  
  CONCLUSIONS
  Vitamin D deficiency and secondary hyperparathyroidism after Roux-en-Y gastric bypass (RYGB) were confirmed in our study because 65 % of patients had vitamin D deficiency, and 69 % had increased PTH levels more than 10 years after surgery. These data are alarming and highlight the need for improved long-term follow-up. Vitamin D deficiency does not seem to progress with time after surgery, possibly due to weight loss. Only preoperative BMI, cutoff point 43 kg/m(2), was a predictor of vitamin D deficiency at follow-up. Improved long-term follow-up of patients that undergo RYGB is needed.
authors.affiliation: Division of Internal Medicine, Department of Endocrinology, Örebro University Hospital, SE-70185, Örebro, Sweden, christos.karefylakis@orebroll.se.
authors.forename: Christos
authors.initials: C
authors.lastname: Karefylakis
authors.forename: Ingmar
authors.initials: I
authors.lastname: Näslund
authors.forename: David
authors.initials: D
authors.lastname: Edholm
authors.forename: Magnus
authors.initials: M
authors.lastname: Sundbom
authors.forename: F Anders
authors.initials: FA
authors.lastname: Karlsson
authors.forename: Eva
authors.initials: E
authors.lastname: Rask
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000378:metabolism*; D015992:Body Mass Index; D002118:Calcium / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000453:epidemiology; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000453:epidemiology; D009767:Obesity, Morbid / Q000097:blood / Q000453:epidemiology / Q000601:surgery*; D010018:Osteomalacia / Q000453:epidemiology; D010281:Parathyroid Hormone / Q000378:metabolism*; D011184:Postoperative Period; D015995:Prevalence; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome; D014807:Vitamin D / Q000378:metabolism*; D014808:Vitamin D Deficiency / Q000097:blood / Q000453:epidemiology; D015431:Weight Loss
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; D000469:Alkaline Phosphatase; D002118:Calcium