title: Changes in Bone Metabolism in Morbidly Obese Patients After Bariatric Surgery: A Meta-Analysis.
abstract: BACKGROUND
  The aim is to evaluate via meta-analysis bone metabolism and bone mineral density (BMD) in morbidly obese patients before and after bariatric surgery.
  
  
  METHODS
  We searched Medline, EMBASE, and the Cochrane Library for relevant studies published before January 2014. The following outcomes were evaluated: serum calcium, serum parathyroid hormone (PTH), serum 25-hydroxyvitamin D [25(OH)D], serum or urinary N-telopeptide (NTX), bone-specific alkaline phosphatase (BSAP), and bone mineral density (BMD).
  
  
  RESULTS
  Ten studies, including 344 patients, met our inclusion criteria. Results showed a significant decrease in serum calcium (MD = -0.10, 95 %CI -0.14 to -0.07, P < 0.00001) and increase in serum PTH (MD = 12.41, 95 %CI 6.51 to 18.31, P < 0.00001) but no significant difference in serum 25(OH)D (MD = 1.35, 95 %CI -1.12 to 3.83, P = 0.28) following bariatric surgery. There were significant increases in serum or urinary NTX (MD = 18.49, 95 %CI 3.33 to 33.66, P = 0.02) and BSAP (MD = 7.47, 95 %CI 0.21 to 14.72, P = 0.04) but a significant decrease in BMD (MD = -0.08, 95 %CI -0.13 to -0.04, P < 0.00001) after bariatric surgery.
  
  
  CONCLUSIONS
  BMD was significantly decreased, while bone turnover was elevated, and bone remodeling was accelerated following bariatric surgery. Basal bone metabolism should be evaluated preoperatively. To prevent secondary hyperparathyroidism and bone loss, calcium and vitamin D should be monitored closely and supplemented accordingly after the surgery.
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, No. 39, Huaxiang Road, Tiexi District, Shenyang, 110022, Liaoning, People's Republic of China. liuc_sjhospital@163.com.
authors.forename: Cong
authors.initials: C
authors.lastname: Liu
authors.affiliation: No. 2 Department of Rheumatology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, People's Republic of China. crystal0553@163.com.
authors.forename: Dan
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, No. 39, Huaxiang Road, Tiexi District, Shenyang, 110022, Liaoning, People's Republic of China. fanfanmail2@126.com.
authors.forename: Jing-Fan
authors.initials: JF
authors.lastname: Zhang
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, No. 39, Huaxiang Road, Tiexi District, Shenyang, 110022, Liaoning, People's Republic of China. xud1@sj-hospital.org.
authors.forename: Duo
authors.initials: D
authors.lastname: Xu
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, No. 39, Huaxiang Road, Tiexi District, Shenyang, 110022, Liaoning, People's Republic of China. xuwf@sj-hospital.org.
authors.forename: Wan-Feng
authors.initials: WF
authors.lastname: Xu
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, No. 39, Huaxiang Road, Tiexi District, Shenyang, 110022, Liaoning, People's Republic of China. 037602@163.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, No. 39, Huaxiang Road, Tiexi District, Shenyang, 110022, Liaoning, People's Republic of China. 119lby@163.com.
authors.forename: Bing-Yang
authors.initials: BY
authors.lastname: Liu
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, No. 39, Huaxiang Road, Tiexi District, Shenyang, 110022, Liaoning, People's Republic of China. s6800@163.com.
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.affiliation: Department of Endocrinology, Shengjing Hospital of China Medical University, No. 39, Huaxiang Road, Tiexi District, Shenyang, 110022, Liaoning, People's Republic of China. liling@sj-hospital.org.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
mesh_terms: D000469:Alkaline Phosphatase / Q000097:blood / Q000652:urine; D050110:Bariatric Surgery; D015519:Bone Density; D016723:Bone Remodeling; D002118:Calcium / Q000097:blood; D024042:Collagen Type I / Q000097:blood / Q000652:urine; D006801:Humans; D009767:Obesity, Morbid / Q000601:surgery; D010281:Parathyroid Hormone / Q000097:blood; D010455:Peptides / Q000097:blood / Q000652:urine; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood
chemical_list: D024042:Collagen Type I; D010281:Parathyroid Hormone; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D000469:Alkaline Phosphatase; D002118:Calcium
keywords: Bariatric surgery; Bone metabolism; Bone mineral density; Morbid obesity; Osteoporosis