Bone Metabolism After Bariatric Surgery

Abstract

Bariatric surgery is a popular and effective treatment for severe obesity, but may have negative effects on the skeleton. This review summarizes changes in bone density and bone metabolism from animal and clinical studies of bariatric surgery, with specific attention to Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB), and sleeve gastrectomy (SG). Skeletal imaging artifacts from obesity and weight loss are also considered. Despite challenges in bone density imaging, the preponderance of evidence suggests that bariatric surgery procedures have negative skeletal effects that persist beyond the first year of surgery, and that these effects vary by surgical type. The long-term clinical implications and current clinical recommendations are presented. Further study is required to determine mechanisms of bone loss after bariatric surgery. Although early studies focused on calcium/vitamin D metabolism and mechanical unloading of the skeleton, it seems likely that surgically-induced changes in the hormonal and metabolic profile may be responsible for the skeletal phenotypes observed after bariatric surgery.

Does Diet-Induced Weight Loss Lead to Bone Loss in Overweight or Obese Adults? A Systematic Review and Meta-Analysis of Clinical Trials

“…Third, the significant increases in circulating concentrations of bone turnover markers suggest a bone catabolic state. It is important to consider bone turnover markers in this field of research, because the accuracy and precision of DXA is known to decrease with increasing BMI (84) and when participants undergo changes in body weight, (85)(86)(87)(88) and because BMD measured at time points earlier than 6 months are not considered to be clinically significant, given that a complete cycle of bone remodeling takes 4 to 6 months. (53) Thus, diet-induced weight loss induces small but statistically significant losses in total hip BMD that would likely not otherwise be seen in overweight or obese individuals.…”

Bone turnover after bariatric surgery

“…The median [IQR] post-surgical time was 4 [1][2][3][4][5][6][7] years and the mean decrease in BMI after surgery was 36% (data not shown in table). As shown in Table 1, no significant differences were observed regarding gender distribution and mean age between BS and Cont.…”

“…However, the procedure entails long-term complications such as nutritional deficiencies, nephrolithiasis (5), as well as other disturbances in bone and mineral metabolism, including low bone mass and increased risk of fractures after a substantial weight loss (6)(7)(8)(9). Bone loss may be attributed to a reduction of lean body mass during the weight reduction process, previous obesity-induced hypovitaminosis D, which persists even after surgery, and malabsorption of calcium and vitamin D following the procedure (10,11).…”

“…Previous studies that evaluated skeletal changes after bariatric surgery through dual-energy x-ray absorptiometry (DXA), quantitative computed tomography (QCT) and high-resolution peripheral computed tomography (HR-pQCT) demonstrated a decreased BMD and also increased bone turnover markers (7,9,(12)(13)(14)(15).…”

Bone Metabolism Changes after Laparoscopic Greater Curvature Plication. A One-Year Study.

“…It belongs to the «safe organ preserving surgery», has a high effi ciency rate and is commonly chosen for treating extreme cases of obesity. However, issues with changes in bone metabolism have recently been brought to light in association to bariatric surgery [6][7][8][9].…”