Gastric bypass and bone health: A systematic review and meta-analysis

Abstract

Introduction: Roux-en-Y gastric bypass (RYGB) is a widely used technique in the management of obesity. Changes in bone analytic parameters and areolar bone mineral density (aBMD) are not yet fully understood in patients that underwent RYGB. The aim of this study is to assess the changes in parameters involved in bone metabolism that occur after RYGB and to understand how these changes contribute to the development of osteoporosis, and occurrence of bone fractures. Methods: The electronic search included three databases. Inclusion criteria were: prospective or retrospective cohort studies, case-control studies, patients with obesity undergoing RYGB, evaluation of changes in bone metabolism parameters, aBMD, osteoporosis and fracture risk. Bone metabolism analytic parameters and aBMD were extracted and analysed. Data is presented in two sets, one year data set and long-term data (≥1 year) set.

Results: Fifteen studies were included in the review, 11 were included in the meta-analysis. In the long term analysis parathyroid hormone (PTH) serum concentration increased and calcium serum concentration decreased. Vitamin D serum concentration increased only in the first year post surgery. Carboxy-terminal collagen crosslinks (CTX) increased substantially both in the first year post-op and in the long-term analysis. There was a global decrease on aBMD in all the studied anatomical regions. No study showed a significant increase in the risk of osteoporosis or bone fracture. Conclusion: RYGB is associated with a prolonged increase in bone turnover which in turn results in long term loss of bone mass. Greater reductions in aBMD were seen in areas associated with greater biomechanical stress. Despite the bone changes described, the occurrence of pathological fractures in the studies was minimal, this complication remains rare in patients undergoing RYGB.