title: Effects of laparoscopic Roux-en-Y gastric bypass on bone mineral density and markers of bone turnover.
abstract: BACKGROUND
  Despite multiple beneficial effects of weight loss after laparoscopic Roux-en-Y gastric bypass (LRYGB), the influence on bone mineral density (BMD) remains largely unknown. Our objective was to evaluate the changes in BMD and serum/urine bone markers after LRYGB.
  
  
  METHODS
  Thirty-four women undergoing LRYGB were prospectively enrolled and underwent bone densitometry and serum/urine analysis preoperatively and 1 year postoperative. Changes≥.025 g/cm(2) in hip, femoral neck, and spine BMD and decreases>2% in total BMD were considered significant. Statistical analysis included paired t tests and McNemar's test.
  
  
  RESULTS
  Mean age was 44.6 years. Body mass index at the preoperative and 1-year postoperative intervals were 46.7 and 29.6 kg/m(2), respectively. Mean hip, femoral neck, and spine (L1-L4) BMD was 1.191 versus 1.087 g/cm(2) (P< .001), 1.105 versus 1.032 g/cm(2) (P< .001), and 1.323 versus 1.277 g/cm(2) (P< .001) at the preoperative and 1 year postoperative intervals, respectively. Mean total BMD decreased from 1.328 preoperatively to 1.251 g/cm(2) at 1 year postoperative (P<.001). The decreases in BMD were 5.8%, 6.5%, 3.5%, and 8.8% for hip, femoral neck, spine (L1-L4) and total BMD from preoperative to 1 year postoperative. The proportion of patients with low vitamin D levels decreased from 55% preoperatively to 21% at 1 year postoperative (P = .004). Elevated osteocalcin and bone alkaline phosphatase was observed in 4% and 63% (P<.001), and 14% and 41% (P = .011) of patients preoperatively and at 1 year postoperative, respectively.
  
  
  CONCLUSIONS
  BMD and bone markers changed significantly after LRYGB. Current recommendations for supplementation in post-LRYGB women may need to be reevaluated.
authors.affiliation: Minimally Invasive Bariatric Surgery and Advanced Laparoscopy Fellowship, Gundersen Health System, La Crosse, Wisconsin.
authors.forename: Kosisochi M
authors.initials: KM
authors.lastname: Obinwanne
authors.affiliation: Department of Surgery, Essentia Health, Duluth, Minnesota.
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Riess
authors.affiliation: Department of Research, Gundersen Medical Foundation, La Crosse, Wisconsin.
authors.forename: Kara J
authors.initials: KJ
authors.lastname: Kallies
authors.affiliation: Department of Research, Gundersen Medical Foundation, La Crosse, Wisconsin.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Mathiason
authors.affiliation: Department of Radiology, Gundersen Health System, La Crosse, Wisconsin.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Manske
authors.affiliation: Department of General and Vascular Surgery, Gundersen Health System, La Crosse, Wisconsin. Electronic address: snkothar@gundersenhealth.org.
authors.forename: Shanu N
authors.initials: SN
authors.lastname: Kothari
mesh_terms: D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D015519:Bone Density / Q000502:physiology*; D001862:Bone Resorption / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology; D015331:Cohort Studies; D019587:Dietary Supplements; D005260:Female; D005500:Follow-Up Studies; D015390:Gastric Bypass / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D010535:Laparoscopy / Q000009:adverse effects / Q000379:methods; D008875:Middle Aged; D009767:Obesity, Morbid / Q000175:diagnosis / Q000601:surgery; D015675:Osteocalcin / Q000097:blood*; D011182:Postoperative Care / Q000379:methods; D011300:Preoperative Care / Q000379:methods; D011446:Prospective Studies; D018570:Risk Assessment; D013997:Time Factors; D014807:Vitamin D / Q000097:blood*
chemical_list: D015415:Biomarkers; D015675:Osteocalcin; D014807:Vitamin D
keywords: Bone density; Bone resorption; Calcium; Gastric bypass; Osteocalcin; Vitamin D