A review examines the negative impacts of weight loss surgery on bone health. The review of published studies notes that weight loss surgery can cause declines in bone mass and strength, and it is linked with an increased risk of bone fractures.
Skeletal changes after surgery appear early and continue even after weight loss plateaus and weight stabilises. Nutritional factors, mechanical unloading, hormonal factors, and changes in body composition and bone marrow fat may contribute to poor bone health.
Most studies have examined the effects of the Roux-en-Y gastric bypass procedure, which was the most commonly performed weight loss procedure worldwide until it was very recently overtaken by sleeve gastrectomy. Because sleeve gastrectomy is a newer procedure, its skeletal effects have not yet been well defined.
The review's findings indicate that clinical guidelines on weight loss surgery should address bone health as a priority. "Current clinical guidelines do address bone health, but most recommendations are based on low-quality evidence or expert opinion," said co-author Dr Anne Schafer, of the University of California – San Francisco and the San Francisco VA Health Care System. "Future studies should address strategies to avoid long-term skeletal consequences of these otherwise beneficial procedures."
Abstract
Bariatric surgery results in long‐term weight loss and improvement or resolution in obesity‐related comorbidities. However, mounting evidence indicates that it adversely affects bone health. This review summarizes clinical research findings about the impact of bariatric surgery on skeletal outcomes. The literature is the largest and strongest for the Roux‐en‐Y gastric bypass (RYGB) procedure, as RYGB was the most commonly performed bariatric procedure worldwide until it was very recently overtaken by the sleeve gastrectomy (SG). Because SG is a newer procedure, its skeletal effects have not yet been well defined. Epidemiologic studies have now demonstrated an increased risk of fracture after RYGB and biliopancreatic diversion with duodenal switch, both of which include a malabsorptive component. As these epidemiologic data have emerged, patient‐oriented studies have elucidated the bone tissue‐level changes that may account for the heightened skeletal fragility. Bariatric surgery induces early and dramatic increases in biochemical markers of bone turnover. A notable feature of recent patient‐oriented clinical studies is the application of advanced skeletal imaging modalities; studies address the limitations of dual‐energy X‐ray absorptiometry (DXA) by using quantitative computed tomography (QCT)‐based modalities to examine volumetric bone mineral density and compartment‐specific density and microstructure. RYGB results in pronounced declines in bone mass at the axial skeleton demonstrated by DXA and QCT, as well as at the appendicular skeleton demonstrated by high‐resolution peripheral quantitative computed tomography (HR‐pQCT). RYGB has detrimental effects on trabecular and cortical microarchitecture and estimated bone strength. Skeletal changes after RYGB appear early and continue even after weight loss plateaus and weight stabilizes. The skeletal effects of bariatric surgery are presumably multifactorial, and mechanisms may involve nutritional factors, mechanical unloading, hormonal factors, and changes in body composition and bone marrow fat. Clinical guidelines address bone health and may mitigate the negative skeletal effects of surgery, although more research is needed to direct and support such guidelines.
Authors
Claudia Gagnon, Anne L Schafer
[link url="https://www.sciencedaily.com/releases/2018/05/180502120005.htm"]Wiley material[/link]
[link url="https://onlinelibrary.wiley.com/doi/abs/10.1002/jbm4.10048"]JBMR Plus abstract[/link]