Relationship Between Bariatric Surgery and Bone Mineral Density: a Meta-analysis

Background: A meta-analysis regarding bone loss after bariatric surgery, designed to compare surgical and nonsurgical groups, has not yet been performed. Therefore, we performed a meta-analysis to compare the differences between bariatric surgical groups and nonoperated controls with regard to bone mineral density. Methods: In March 2015, we performed a review of the literature using PubMed, EMBASE, and the Cochrane Library. The search focused on retrospective and prospective studies, including but not limited to randomized studies published in English. Results: Among 1299 studies that were initially screened, ten met the selection criteria. For all types of bariatric surgery, bone density at the femoral neck was lower in the surgical group than in the nonsurgical control group (mean difference [MD] −0.05 g/cm²; 95 % confidence interval [CI], −0.07 to −0.02; p = 0.001); no difference in bone density was found between the two groups at the lumbar spine (MD −0.01 g/cm²; 95 % CI −0.07 to 0.05; p = 0.661). The analysis of Roux-en-Y gastric bypass showed similar results. Conclusion: Bone density at the femoral neck decreased after bariatric surgery, compared to that in nonsurgical controls, whereas bone density at the lumbar spine did not show a difference between groups. Further larger scale studies with comparative nonsurgical controls are warranted to overcome the heterogeneity among studies in this analysis and to add evidence of possible bone loss subsequent to bariatric surgical procedures.