Changes in bone metabolism and densitometry after metabolic/bariatric surgery: a comparison of pre- and postoperative results in a prospective long-term study
In brief
Bariatric surgery halves femoral bone density after ten years
In a 10-year follow-up of 60 patients, femoral neck bone mineral density dropped from about 1.0 g/cm² to roughly 0.5 g/cm² across sleeve gastrectomy, Roux-en-Y gastric bypass and one-anastomosis gastric bypass, while lumbar spine density stayed stable. Vitamin D levels rose with supplementation, but FRAX scores indicated higher 10-year fracture risk, prompting calls for routine bone health monitoring after bariatric procedures.
- Journal
- Surgery for obesity and related diseases : official journal of the American Society for Bariatric Surgery (Q1)
- Published
- 30 July 2026
- Study design
- Prospective / inception cohort
- Evidence level
- Level 2, Moderate (CEBM 2b)
- Authors
- Daniel M Felsenreich, Natalie Vock, Lea Pedarnig, Benjamin Fiedler, Iris M Nöbauer-Huhmann, Julia Jedamzig, et al.
- PMID
- 42624709
- DOI
- 10.1016/j.soard.2026.07.018
Why clinicians should know about it
- Picked for Bariatric and Metabolic Surgery (paper of the day, 21 August 2026): Long‑term bone loss after SG, RYGB, OAGB
Abstract
BACKGROUND: Metabolic and bariatric surgery (MBS) is associated with sustained weight loss and metabolic improvement. However, the understanding of its long-term effects on skeletal health remains incomplete, particularly with respect to different surgical procedures. OBJECTIVES: This study aimed to evaluate long-term changes in bone metabolism, bone mineral density (BMD), and fracture risk after sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and one-anastomosis gastric bypass (OAGB). SETTING: University hospital. METHODS: In this retrospective cohort with prospective long-term follow-up, 60 patients (20 RYGB, 20 OAGB, and 20 SG) underwent primary MBS. Dual-energy X-ray absorptiometry-derived bone densitometry and bone metabolism markers were assessed preoperatively and after a mean follow-up of 10.1± 2.5 years. Measurements included BMD, T-score, and z score at lumbar spine and femoral neck. Ten-year fracture probability was estimated using the FRAX (Fracture Risk Assessment tool) score. RESULTS: Bone metabolism markers largely remained within reference ranges throughout follow-up. Serum vitamin D levels increased significantly after all procedures reflecting postoperative supplementation. In contrast, significant reductions in femoral BMD was observed after all three procedures (SG: .99 ± .14 to .49 ± .17 g/cm2, P = .03; RYGB: 1.09 ± .80 to .59 ± .17 g/cm2, P = .02; OAGB: 1.11 ± .18 to .53 ± .13 g/cm2, P = .01), whereas lumbar spine BMD showed no significant change. FRAX-estimated 10-year risk for major osteoporosis and hip fractures was elevated at long-term follow-up. CONCLUSIONS: Despite largely preserved biochemical bone markers, substantial long-term structural bone loss and increased fracture risk were observed after MBS. These findings support the consideration of routine postoperative bone health surveillance following MBS to allow early therapeutic intervention when indicated.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.