title: Effect of gastric bypass on vitamin D and secondary hyperparathyroidism.
abstract: Obesity as well as bariatric surgery may increase the risk for vitamin D deficiency. We retrospectively compared vitamin D levels in obese patients (n = 123) prior to bariatric surgery and 1 year postoperatively. We also evaluated parathyroid hormone levels (PTH) 1 year after surgery. A higher percentage of patients had baseline vitamin D deficiency (86%), defined as 25-hydroxy vitamin D <32 ng/mL, compared with the 1-year (post-surgical) levels, (70%; p < 0.001). Body mass index (BMI) inversely correlated with vitamin D deficiency at baseline (r = -0.3, p = 0.06) and at the postoperative follow-up (r = -0.2, p = 0.013). One third of the postoperative population had secondary hyperparathyroidism, defined by a serum PTH level >62 pg/mL; however, postoperative PTH and vitamin D levels were unrelated (r = -0.001, p = 0.994). Pre- and postoperative vitamin D levels were inversely correlated with BMI. Secondary hyperparathyroidism was observed in 33% of patients postoperatively; however, this did not correlate with vitamin D.
authors.affiliation: Divisions of Cardiology, Nutrition and Preventive Medicine, Department of Medicine, William Beaumont Hospital, Royal Oak, MI 48073, USA.
authors.forename: Carina
authors.initials: C
authors.lastname: Signori
authors.forename: Kerstyn C
authors.initials: KC
authors.lastname: Zalesin
authors.forename: Barry
authors.initials: B
authors.lastname: Franklin
authors.forename: Wendy L
authors.initials: WL
authors.lastname: Miller
authors.forename: Peter A
authors.initials: PA
authors.lastname: McCullough
mesh_terms: D015992:Body Mass Index; D002118:Calcium / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000009:adverse effects*; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D009767:Obesity, Morbid / Q000097:blood* / Q000150:complications / Q000601:surgery*; D010281:Parathyroid Hormone / Q000097:blood; D011184:Postoperative Period; D012189:Retrospective Studies; D012306:Risk; D014807:Vitamin D / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology / Q000209:etiology*; D015431:Weight Loss
chemical_list: D010281:Parathyroid Hormone; D014807:Vitamin D; D002118:Calcium