title: Bone mineral density after bariatric surgery. A systematic review.
abstract: OBJECTIVE
  Bone regulation system may be affected after bariatric surgeries, but procedures impact differently to bone mineral density (BMD) and measures restraining bone loss are frequently neglected until clinical consequences become manifest. This is a systematic review aimed to elucidate whether BMD loss is comparable after different bariatric surgeries.
  
  
  METHODS
  A search of morbid obese adults, undergone to bariatric surgery, with BMD measured by dual-energy X-ray absorptiometry at baseline and after surgery studies was performed in several databases. Studies were assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and COCHRANE Risk of Bias tool. The random model was selected for meta-analysis; heterogeneity was analyzed with T(2), inconsistency (I(2) > 50%) and Chi(2) (p < 0.10). Level of evidence and strength of recommendations were summarized using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE System).
  
  
  RESULTS
  Twelve studies met the selection criteria. After one year, reduction in total BMD in patients with mixed surgical procedures was significant: -0.03 g/cm(2) (CI 95% 0.00 to -0.06, p < 0.05). BMD was reduced by -0.12 g/cm(2) (CI 95% -0.10 to -0.15, p < 0.001) in the hip, -0.07 g/cm(2) (CI 95% -0.03 to -0.11, p < 0.001) in the column, and -0.03 g/cm(2) (IC 95% -0.02 to -0.04, p < 0.001) in the forearm, but not in restrictive surgeries. Studies included showed high heterogeneity and low quality of evidence.
  
  
  CONCLUSIONS
  Patients undergone to mixed bariatric surgery had significant higher BMD deterioration as demonstrated in this review, suggesting that more attention for preventing fractures is required.
authors.affiliation: Nutrigenetics and Nutrigenomics Laboratory, Instituto Nacional de Medicina Genómica, Periférico Sur 4809, Arenal Tepepan, Tlalpan, CP 14610 Mexico City, Mexico. Electronic address: yanrdz@gmail.com.
authors.forename: Yanelli
authors.initials: Y
authors.lastname: Rodríguez-Carmona
authors.affiliation: Universidad Autónoma Metropolitana Unidad Xochimilco, Calzada del Hueso 1100, Villa Quietud, Coyoacán, CP 04960 Mexico City, Mexico. Electronic address: flas20@hotmail.com.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: López-Alavez
authors.affiliation: Department of Research Methodology, Instituto Nacional de Pediatría, Insurgentes Sur 3700C, Insurgentes Cuicuilco, Coyoacán, CP 04530 Mexico City, Mexico. Electronic address: pegasso.100@hotmail.com.
authors.forename: Alejandro G
authors.initials: AG
authors.lastname: González-Garay
authors.affiliation: Instituto Nacional de Pediatría, Insurgentes Sur 3700C, Insurgentes Cuicuilco, Coyoacán, CP 04530 Mexico City, Mexico. Electronic address: solisgc@yahoo.com.mx.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Solís-Galicia
authors.affiliation: Hospital General de México "Dr. Eduardo Liceaga", Dr. Balmis 148 Col. Doctores, Cuauhtémoc, CP 06726 Mexico City, Mexico. Electronic address: melendez651@gmail.com.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Meléndez
authors.affiliation: Clinical Nutrition, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Vasco de Quiroga 15, Sección XVI Tlalpan, CP 14000, Mexico City, Mexico. Electronic address: aurozabeth@yahoo.com.mx.
authors.forename: Aurora E
authors.initials: AE
authors.lastname: Serralde-Zúñiga
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000009:adverse effects* / Q000379:methods; D015519:Bone Density; D005260:Female; D050723:Fractures, Bone / Q000517:prevention & control; D006801:Humans; D008297:Male
keywords: Biliopancreatic diversion; Bone mineral density; Gastroplasty; Roux-in-Y gastric bypass; Vertical banded gastroplasty