Bone Health After Bariatric Surgery

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.

Fractures in Adults After Weight Loss from Bariatric Surgery and Weight Management Programs for Obesity: Systematic Review and Meta-analysis

“…There have been a number of systematic reviews and metaanalyses reporting on the association between bariatric surgery, particularly malabsorptive surgery, and significant BMD loss at the hip with less consistent results for the lumbar spine [2,[24][25][26]. However, the studies were sometimes without comparator groups and are difficult to interpret due to imaging limitations in severe obesity [27]. In a meta-analysis of five cohort studies and one RCT, Zhang and colleagues reported that bariatric surgery was associated with fractures at non-vertebral sites, especially upper limb fractures [28].…”

“…The potential mechanisms underlying reductions in bone density and strength from weight loss which may precipitate bone fracture include mechanical, hormonal changes, and malabsorptive factors [27]. The reduction in force placed upon bones due to weight loss leads to higher levels of sclerostin, which inhibits osteoblastic activity and bone formation [27], while markers of bone turnover are considerably increased [4,27]. Furthermore, estrogen and androgen status may decline particularly in postmenopausal women after bariatric surgery [29].…”

Body Weight and Body Mass Index Influence Bone Mineral Density in Late Adolescence in a Two‐Year Follow‐Up Study. The Tromsø Study: Fit Futures

“…The determinants of bone acquisition in the period of late adolescence to early adulthood are understudied, and there are a limited number of studies of weight change and bone in a comparable population. Most studies are among pre‐, peri‐, and postmenopausal women, in relation to weight‐reduction interventions, eating disorders, use of medications, or bariatric surgery . Studies on anorexia nervosa in adolescence are not directly comparable, but longitudinal studies of weight gain and restoration of BW show significant, although slow, improvement and normalization of aBMD levels .…”

Management of Bone Fragility in a Patient with Type 2 Diabetes Mellitus

“…It is unclear whether sleeve gastrectomy is safe for skeletal health as it is a new procedure, and its skeletal e ects have not been well de ned. 41…”