Fracture Risk After Bariatric Surgery: Roux-en-Y Gastric Bypass Versus Adjustable Gastric Banding

Bone health in adults with obesity before and after interventions to promote weight loss

Obesity and its associated comorbidities constitute a serious and growing public health burden. Fractures affect a substantial proportion of people with obesity and result from reduced bone strength relative to increased mechanical loading, together with an increased risk of falls. Factors contributing to fractures in people with obesity include adverse effects of adipose tissue on bone and muscle and, in many people, the coexistence of type 2 diabetes. Strategies to reduce weight include calorie-restricted diets, exercise, bariatric surgery, and pharmacological interventions with GLP-1 receptor agonists. However, although weight loss in people with obesity has many health benefits, it can also have adverse skeletal effects, with increased bone loss and fracture risk. Priorities for future research include the development of effective approaches to reduce fracture risk in people with obesity and the investigation of the effects of GLP-1 receptor agonists on bone loss resulting from weight reduction.

Risk of fractures following bariatric surgery with Roux-en-Y gastric bypass or sleeve gastrectomy: a Danish population-based cohort study

OBJECTIVE

We examined the association between Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) and fracture risk, including major osteoporotic fractures (MOF), and the use of anti-osteoporosis medication (AOM). While RYGB is associated with impaired bone health and increased fracture risk, it remains uncertain whether SG has a similar impact and whether this risk is primarily due to MOF or any fracture.

DESIGN

We conducted a nationwide cohort study covering patients treated with RYGB (n = 16 121, 10.2-year follow-up) or SG (n = 1509, 3.7-year follow-up), from 2006 to 2018, comparing them with an age- and sex-matched cohort (n = 407 580).

METHODS

We computed incidence rates and adjusted hazard ratios (HRs) with 95% CIs, using Cox regression for any fracture, MOF, and use of AOM with adjustment for comorbidities.

RESULTS

Compared with the general population cohort, RYGB was associated with an increased risk of any fracture (HR 1.56 [95% CI, 1.48-1.64]) and MOF (HR 1.49 [1.35-1.64]). Sleeve gastrectomy was associated with an increased risk of any fracture (HR 1.38 [1.13-1.68]), while the HR of MOF was 1.43 (0.97-2.12). The use of AOM was low but similar in all cohorts (approximately 1%).

CONCLUSIONS

Bariatric surgery increased the risk of any fracture and MOF to similar extend. Risks were similar for RYGB and SG. However, SG had a shorter follow-up than RYGB, and the cohort size was rather small. More research is needed for long-term SG fracture risk assessment. The use of AOM was low in all cohorts.

Intersession reliability of lower limb muscle strength assessments in adults with obesity eligible for bariatric surgery

BACKGROUND

The aim of this study was to examine the test-retest reliability in lower limb muscle strength and rate of torque development (RTD) using isokinetic dynamometry in adults with obesity, with a body mass index (BMI) ≥ 35 kg/m2.

METHOD

Thirty-two adults with a BMI of 43.8 ± 6.6 kg/m2 eligible for bariatric surgery were enroled in the study. Isokinetic and isometric knee extensor (KE) and flexor (KF) strength were assessed in an isokinetic dynamometer (Biodex 4) during three test sessions separated by 3-7 days.

RESULTS

There were no statistical differences in peak KE and KF torque for any test modalities between sessions. Intraclass correlation (ICC) was 0.91-0.94 between sessions 1 and 2 and 0.94-0.97 between sessions 2 and 3. Standard error of measurement (SEM%) and coefficient of variation (CV) ranged across test sessions from 4.3% to 7.3%. KE RTD showed high test-retest reliability following familiarization, with ICC, CV and SEM% values ranging from 0.84 to 0.90, 13.3%-20.3% and 14.6%-24.9%, respectively.

CONCLUSION

Maximal lower limb muscle strength measured by isokinetic dynamometry showed excellent test-retest reliability manifested by small measurement errors and low CV. Reliability was slightly improved by including a familiarization session. KE RTD but not KF RTD demonstrated high test-retest reliability following familiarization. The present data indicate that isokinetic dynamometry can be used to detect even small changes in lower limb muscle strength in adults with obesity.

Skeletal effects of sleeve gastrectomy, by sex and menopausal status and in comparison to Roux-en-Y gastric bypass surgery

Context

Roux-en-Y gastric bypass (RYGB) has deleterious effects on bone mass, microarchitecture, and strength. Data are lacking on the skeletal effects of sleeve gastrectomy (SG), now the most commonly performed bariatric surgical procedure.

Objective

We examined changes in bone turnover, areal and volumetric bone mineral density (aBMD, vBMD), and appendicular bone microarchitecture and estimated strength after SG. We compared the results to those previously reported after RYGB, hypothesizing lesser effects after SG than RYGB.

Design Setting Participants

Prospective observational cohort study of 54 adults with obesity undergoing SG at an academic center.

Main Outcome Measures

Skeletal characterization with biochemical markers of bone turnover, dual-energy X-ray absorptiometry (DXA), quantitative computed tomography (QCT), and high-resolution peripheral QCT (HR-pQCT) was performed preoperatively and 6- and 12-months postoperatively.

Results

Over 12 months, mean percentage weight loss was 28.8%. Bone turnover marker levels increased, and total hip aBMD decreased -8.0% (95% CI -9.1%, -6.7%, p<0.01). Spinal aBMD and vBMD declines were larger in postmenopausal women than men. Tibial and radial trabecular and cortical microstructure worsened, as did tibial estimated strength, particularly in postmenopausal women. When compared to data from a RYGB cohort with identical design and measurements, some SG biochemical, vBMD, and radial microstructural parameters were smaller, while other changes were not.

Conclusions

Bone mass, microstructure, and strength decrease after SG. Some skeletal parameters change less after SG than after RYGB, while for others, we find no evidence for smaller effects after SG. Postmenopausal women may be at highest risk of skeletal consequences after SG.

Fat as a Friend or Foe of the Bone

PURPOSE OF REVIEW

The objective of this review is to summarize the literature on the prevalence and diagnosis of obesity and its metabolic profile, including bone metabolism, focusing on the main inflammatory and turnover bone mediators that better characterize metabolically healthy obesity phenotype, and to summarize the therapeutic interventions for obesity with their effects on bone health.

RECENT FINDINGS

Osteoporosis and fracture risk not only increase with age and menopause but also with metabolic diseases, such as diabetes mellitus. Thus, patients with high BMI may have a higher bone fragility and fracture risk. However, some obese individuals with healthy metabolic profiles seem to be less at risk of bone fracture. Obesity has become an alarming disease with growing prevalence and multiple metabolic comorbidities, resulting in a significant burden on healthcare and increased mortality. The imbalance between increased food ingestion and decreased energy expenditure leads to pathological adipose tissue distribution and function, with increased secretion of proinflammatory markers and harmful consequences for body tissues, including bone tissue. However, some obese individuals seem to have a healthy metabolic profile and may not develop cardiometabolic disease during their lives. This healthy metabolic profile also benefits bone turnover and is associated with lower fracture risk.

Bone mineral density in young adults 5 to 11 years after adolescent metabolic and bariatric surgery for severe obesity compared to peers

OBJECTIVE

Metabolic and bariatric surgery (MBS) is associated with decreased bone mineral density (BMD) in adults. The long-term impact of MBS during adolescence on BMD is unknown. We report bone health status 5 to 11 years after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) from the Teen-LABS study cohort.

METHODS

Between 2016 and 2022, BMD was measured by dual energy x-ray absorptiometry (DXA) in 106 young adults who had undergone MBS as adolescents. Volumetric BMD by peripheral quantitative computed tomography was measured on a subset. Ninety-one controls who had not undergone MBS were recruited for comparison.

RESULTS

In cases (RYGB: mean age 26.8 ± 1.9 years, mean BMI 42.1 ± 9.9 kg/m2, VSG: mean age 25.1 ± 2.1 years, mean BMI 37.1 ± 8.4 kg/m2), compared to controls (mean age 26.5 ± 2.7 years, mean BMI 40.2 ± 8.7 kg/m2) (age p < 0.001, BMI p = 0.02), adjusted mean DXA-BMD (g/cm2) of the RYGB (n = 58) and VSG (n = 48) groups were lower at the hip (-10.0% and -6.3%), femoral neck (-9.6% and -5.7%) and ultra-distal radius (-7.9% and -7.0%; all p < 0.001), respectively. DXA-BMD did not differ between RYGB and VSG groups. Trabecular volumetric BMD at the radius and tibia were lower in the RYGB (-30% and -26%) and VSG (-15% and -14%) groups compared to the control group (p < 0.001). Greater time since MBS was associated with lower BMD Z-scores at the hip (p = 0.05) and femoral neck (p = 0.045). Percent change in body mass index (BMI) from baseline or in the first year after MBS were not associated with bone measures at a median of 9.3 years post MBS.

CONCLUSION

BMD, especially of the hip and femoral neck, was lower in young adults who underwent MBS during adolescence compared to matched peers who had not undergone MBS. BMD Z-scores of the femoral neck were inversely associated with time since MBS but were not associated with BMI change.

Risk of wrist fracture, estimated by the load-to-strength ratio, declines following sleeve gastrectomy in adolescents and young adults

To understand whether the bone loss which occurs after vertical sleeve gastrectomy increases the risk of fracture, we used an engineering model to estimate risk in participants before and after surgery. We found that estimated risk decreased 1 year after surgery and remained lower, though had rebounded, at year 2.

PURPOSE

Vertical sleeve gastrectomy (VSG) improves metabolic health in young people with obesity but is accompanied by substantial loss of bone mass and estimated bone strength. We thus estimated fracture risk following VSG using the load-to-strength ratio (LSR), which integrates bone strength estimates with the predicted force of a fall.

METHODS

Prospective 2-year study of youth ages 13-24 years with obesity undergoing VSG (n = 24) or lifestyle therapy (n = 34). We performed high-resolution peripheral quantitative computed tomography of the distal radius and microfinite element analysis to estimate bone strength and calculated LSR.

RESULTS

VSG participants lost 26.4 ± 8.1% weight at year 1 (p < 0.001), which was sustained at year 2, while control participants gained weight at year 2 (4.5 ± 8.3%, p = 0.009). The predicted impact force decreased at years 1 and 2 following VSG (p < 0.001) but increased at year 2 among controls (p = 0.011). Estimated bone strength was unchanged at year 1 but decreased (p < 0.001) at year 2 following VSG, while bone strength did not change in controls. At year 1, the LSR decreased among VSG participants (p < 0.001), implying a lower risk of fracture. At year 2, the LSR was lower than baseline (p < 0.001), but higher compared to year 1 (p = 0.001). LSR did not change in the control group.

CONCLUSIONS

Short-term estimated fracture risk at the radius following VSG decreases. However, ongoing bone loss despite stable weight between years 1 and 2 leads to a concerning rise in estimated fracture risk. Longer follow-up will be critical to evaluate the trajectory of fracture risk. (ClinicalTrials.gov NCT02557438, registered 9/23/2015).

Bone mineral density 5 to 11 years after metabolic and bariatric surgery in adolescents with severe obesity compared to peers

Objective

Metabolic and bariatric surgery (MBS) is associated with decreased bone mineral density (BMD) in adults. The long-term impact of MBS during adolescence on BMD is unknown. We report bone health status 5 to 11 years after Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) from the Teen-LABS study cohort.

Methods

Between 2016 and 2022, BMD was measured by dual energy x-ray absorptiometry (DXA) in 106 young adults who had undergone MBS as adolescents. Volumetric BMD by peripheral quantitative computed tomography was measured on a subset. Ninety-one controls who had not undergone MBS were recruited for comparison.

Results

Compared to controls, adjusted mean DXA-BMD of the RYGB (n = 58) and VSG (n = 48) groups were lower at the hip (-10.0% and - 6.3%), femoral neck (-9.6% and - 5.7%) and ultra-distal radius (-7.9% and - 7.0%; all p < 0.001), respectively. DXA-BMD did not differ between RYGB and VSG groups. Trabecular volumetric BMD at the radius and tibia were lower in the RYGB (-30% and - 26%) and VSG (-15% and - 14%) groups compared to the control group (p < 0.001). Greater time since MBS was associated with lower BMD Z-scores at the hip (p = 0.05) and femoral neck (p = 0.045). Percent change in body mass index (BMI) from baseline or in the first year after MSB were not associated with bone measures at a median of 9.3 years post MSB.

Conclusion

BMD, especially of the hip and femoral neck, was lower in young adults who underwent MBS during adolescence compared to matched peers who had not undergone MBS. BMD Z-scores of the femoral neck decreased with time since MBS but were not associated with BMI change.

Effect of catgut embedding at acupoints versus non-acupoints in abdominal obesity: a randomized clinical trial

OBJECTIVE

To explore the difference of catgut embedding effect between acupoints and non-acupoints in patients with abdominal obesity (AO).

METHODS

In this multicenter, double-blind, randomized controlled trial, all subjects were randomly assigned into the acupoint catgut embedding (ACE) group and control group (catgut embedding at non-acupoints). With a 12-week actual intervention period and a 4-week period of follow-up. Waist circumference (WC), body weight, body mass index (BMI), hip circumference (HC) and appetite were applied and assessed at baseline and after 6, 12 and 16 weeks.

RESULTS

After the total intervention phase (12 weeks), the WC, body weight, BMI, HC and visual analogue scale scores of appetite, decreased significantly in the two groups as compared to the baseline (0.001). Meanwhile, after the 4-week follow-up, the indicators still decreased significantly in the ACE group (0.001). At 12 and 16 weeks, catgut embedding at acupoints showed significantly advantages to non-acupoints in WC and appetite (0.05). No serious adverse events were observed in ACE group and control group.

CONCLUSIONS

Catgut embedding at acupoints and non-acupoints are all effective and safe for AO. ACE can effectively treat AO as expected and deliver lasting results.

The Effect of Catgut Embedding at Acupoints Versus Nonacupoints in Abdominal Obesity: Protocol for a Multicenter, Double-Blind, 16-Week Randomized Controlled Trial

BACKGROUND

Obesity is an increasing problem worldwide. The effective treatments for obesity mainly include diet, physical activity, behavioral intervention, pharmacotherapy, and bariatric surgery, which all have certain limitations. As a specific type of acupuncture therapy, acupoint catgut embedding (ACE) has gained substantial attention in the management of obesity in recent years. Previous studies suggested that ACE may be an effective obesity treatment. However, the evidence for the efficacy of ACE in abdominal obesity (AO) remains inadequate due to the paucity of high-quality studies.

OBJECTIVE

This study aims to investigate the difference in the effectiveness of catgut embedding at acupoints and catgut embedding at nonacupoints in patients with AO and to further validate the efficacy and safety of ACE for AO.

METHODS

This is a multicenter, double-blind, 16-week randomized controlled trial. A total of 92 eligible participants with AO will be randomly divided into 2 groups (1:1 allocation ratio). The ACE group will receive catgut embedding at acupoints and the control group will receive catgut embedding at nonacupoints. The intervention will be performed every 2 weeks for a total of 6 sessions. Follow-up will be performed every 2 weeks for a total of 2 visits. The primary outcome is waist circumference. Secondary outcomes include body weight, BMI, hip circumference, and the visual analog scale of appetite. Upon the completion of the trial, we will evaluate the effect of catgut embedding at acupoints or nonacupoints on obesity indicators in patients with AO. For treatment outcomes, an intention-to-treat analysis will be performed.

RESULTS

The start of recruitment began in August 2019 and is expected to end in September 2023.

CONCLUSIONS

Although studies have been conducted to demonstrate the effectiveness of ACE in the treatment of obesity, the evidence for the efficacy of ACE in AO remains insufficient due to the quality of the studies. This rigorous normative randomized controlled trial will verify the effect of catgut embedding at acupoints or nonacupoints in patients with AO. The findings will provide credible evidence as to whether ACE is an effective and safe treatment for AO.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR1800016947; https://tinyurl.com/2p82257p.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/46863.

Skeletal Effects of Sleeve Gastrectomy in Adolescents and Young Adults: A 2-Year Longitudinal Study

CONTEXT

Vertical sleeve gastrectomy (VSG) is an increasingly common tool to achieve weight loss and improve metabolic health in adolescents and young adults with obesity, although it may adversely affect bone health.

OBJECTIVE

This work aimed to evaluate the effect of VSG on bone health in youth.

METHODS

An observational 2-year study was conducted at a tertiary care center of 66 patients aged 13 to 24 years with moderate-to-severe obesity meeting criteria for VSG. The patients underwent VSG (n = 30) or nonsurgical (n = 36) management per the decision of patient and clinical team. Main outcome measures included dual-energy x-ray absorptiometry (DXA) and high-resolution peripheral quantitative computed tomography (HRpQCT) measures of bone mineral density (BMD), geometry, and microarchitecture.

RESULTS

VSG patients achieved 25.3 ± 2.0% weight loss at 2 years (P < .001) while control subjects gained 4.0 ± 2.0% (P = .026). Total hip BMD declined 8.5 ± 1.0% following VSG compared with 0.1 ± 1.0% gain in controls (P < .001), with similar results at the femoral neck (P < .001). Total volumetric BMD (vBMD) decreased both at the distal radius and tibia following VSG (P < .001) driven primarily by trabecular vBMD loss (P < .001). Two-year changes in cortical vBMD did not differ between groups, though cortical porosity decreased following VSG both at the radius and tibia (P = .048 and P < .001). Cortical thickness increased in controls but not in VSG (P = .022 and P = .002 for between-group comparisons at the radius and tibia, respectively). Following VSG, estimated failure load decreased at the radius and did not demonstrate the physiologic increases at the tibia observed in controls.

CONCLUSION

VSG leads to progressive changes in bone health over 2 years, and may lead to increased skeletal fragility in adolescents and young adults.

Intestinal Calcium Absorption Decreases After Laparoscopic Sleeve Gastrectomy Despite Optimization of Vitamin D Status

CONTEXT

Laparoscopic sleeve gastrectomy (LSG), now the most commonly performed bariatric operation, is a highly effective treatment for obesity. While Roux-en-Y gastric bypass is known to impair intestinal fractional calcium absorption (FCA) and negatively affect bone metabolism, LSG's effects on calcium homeostasis and bone health have not been well characterized.

OBJECTIVE

We determined the effect of LSG on FCA, while maintaining robust 25-hydroxyvitamin D (25OHD) levels and recommended calcium intake.

DESIGN, SETTING, PARTICIPANTS

Prospective pre-post observational cohort study of 35 women and men with severe obesity undergoing LSG.

MAIN OUTCOMES

FCA was measured preoperatively and 6 months postoperatively with a gold-standard dual stable isotope method. Other measures included calciotropic hormones, bone turnover markers, and bone mineral density (BMD) by dual-energy X-ray absorptiometry and quantitative computed tomography.

RESULTS

Mean ± SD FCA decreased from 31.4 ± 15.4% preoperatively to 16.1 ± 12.3% postoperatively (P < 0.01), while median (interquartile range) 25OHD levels were 39 (32-46) ng/mL and 36 (30-46) ng/mL, respectively. Concurrently, median 1,25-dihydroxyvitamin D level increased from 60 (50-82) pg/mL to 86 (72-107) pg/mL (P < 0.01), without significant changes in parathyroid hormone or 24-hour urinary calcium levels. Bone turnover marker levels increased substantially, and areal BMD decreased at the proximal femur. Those with lower postoperative FCA had greater areal BMD loss at the total hip (ρ = 0.45, P < 0.01).

CONCLUSIONS

FCA decreases after LSG, with a concurrent rise in bone turnover marker levels and decline in BMD, despite robust 25OHD levels and with recommended calcium intake. Decline in FCA could contribute to negative skeletal effects following LSG.

Zoledronic Acid for prevention of bone and muscle loss after BAriatric Surgery (ZABAS)-a study protocol for a randomized controlled trial

Background

Bariatric surgery has adverse effects on the muscular-skeletal system with loss of bone mass and muscle mass and an increase in the risk of fracture. Zoledronic acid is widely used in osteoporosis and prevents bone loss and fracture. Bisphosphonates may also have positive effects on skeletal muscle. The aim of this study is to investigate the effects of zoledronic acid for the prevention of bone and muscle loss after bariatric surgery. 

Methods/design

This is a randomized double-blind placebo-controlled study. Sixty women and men with obesity aged 35 years or older will complete baseline assessments before randomization to either zoledronic acid (5 mg in 100 ml isotonic saline) or placebo (100 ml isotonic saline only) 3 weeks before surgery with Roux-en-Y-gastric bypass (RYGB) or sleeve gastrectomy (SG). Follow-up assessments are performed 12 and 24 months after surgery. The primary outcome is changes in lumbar spine volumetric bone mineral density (vBMD) assessed by quantitative computed tomography (QCT). Secondary bone outcomes are changes in proximal femur vBMD assessed by QCT. Changes in cortical and trabecular bone microarchitecture and estimated bone strength will be assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT). Cortical material bone strength at the mid-tibia diaphysis will be assessed using microindentation and fasting blood samples will be obtained to assess biochemical markers of bone turnover and calcium metabolism. 

Secondary muscle outcomes include whole body lean mass assessed using dual-energy X-ray absorptiometry. Dynamometers will be used to assess handgrip, shoulder, ankle, and knee muscle strength. Short Physical Performance Battery, 7.6-m walking tests, 2-min walking test, and a stair climb test will be assessed as biomarkers of physical function. Self-reported physical activity level is assessed using International Physical Activity Questionnaire (IPAQ).

Discussion

Results from this study will be instrumental for the evidence-based care of patients undergoing bariatric surgery.

Trial registration

ClinicalTrials.gov NCT04742010. Registered on 5 February 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06766-z.

Insulin-like growth factor binding protein 2 null mice (Igfbp2-/-) are protected against trabecular bone loss after vertical sleeve gastrectomy

BACKGROUND

Bariatric surgery has been shown to result in weight loss, improved hemoglobin A1C, and decreased mortality but can also lead to bone loss and increased fracture rates. Serum IGFBP-2 is elevated in patients after bariatric surgery and although it may lead to improved blood glucose, may also drive bone resorption, and inhibit IGF-I action. This study tested the hypothesis that Igfbp2-/- mice were acutely protected from bone loss after vertical sleeve gastrectomy (VSG).

METHODS

Thirty-four mice, 17 Igfbp2-/- and 17 + / + underwent a hand-sewn VSG or sham surgery, at 16 weeks of age. Mice were harvested at 20 weeks of age. DXA was measured for body composition, areal bone mineral density (aBMD), areal bone mineral content (aBMC), femoral bone mineral density (fBMD), and femoral bone mineral content (fBMC) at 15, 18, and 20 weeks of age. Micro-computed tomography and serum ELISA assays were measured and analyzed at 20 weeks of age.

RESULTS

Both Igfbp2-/- and + / + mice lost significant weight (P = 0.0251, P = 0.0003, respectively) and total fat mass (P = 0.0082, P = 0.0004, respectively) at 4 weeks after VSG. Igfbp2+/+ mice lost significant aBMD, fBMD, fBMC, trabecular BMD, trabecular BV/TV and cortical tissue mineral density (P = 0.0150, P = 0.0313, P = 0.0190, P = 0.0072, and 0.0320 respectively). The Igfbp2-/- mice did not show significant bone loss in these parameters nor in trabecular BV/TV. Both Igfbp2-/- and + / + mice had less cortical bone area (P = 0.0181, P =  < .00001), cortical area over total area (P = 0.0085, P = 0.0007), and cortical thickness (P = 0.0050, P =  < 0.0001), respectively. Igfbp2+/+ mice demonstrated significantly lower polar, minimum, and maximum moments of inertia (P = 0.0031, P = 0.0239, and P = 0.0037, respectively). Igfbp2+/+ had significantly higher levels of IGFBP-2 at 2 weeks postoperatively after VSG (P = 0.035), and elevated levels of CTx and P1NP (P = 0.0127, P = 0.0058, respectively).

CONCLUSIONS

Igfbp2-/- mice were protected against trabecular bone loss and had attenuated cortical bone loss 4 weeks after VSG.

Changes in volumetric bone mineral density and bone quality after Roux-en-Y gastric bypass: A meta-analysis with meta-regression

This meta-analysis aimed to assess the effect of Roux-en-Y gastric bypass (RYGB) on three-dimensionally assessed volumetric bone mineral density (vBMD) with the effect of time on these changes, on bone quality, and the agreement of dual-energy X-ray absorptiometry (DXA) with quantitative computed tomography (QCT) or high-resolution peripheral QCT (HR-pQCT) estimates of bone loss. We searched PubMed, Web of Science, Cochrane, Scopus, and EBSCO. Longitudinal studies on adults undergoing RYGB in which vBMD was assessed by QCT or HR-pQCT with ≥6 months follow-up were included. Total hip (TH) changes were reported in four studies, lumbar spine (LS) in eight, radius in eight, and tibia in seven. Significant post-RYGB vBMD reductions occurred at all skeletal sites analyzed. Meta-regression revealed that time post-RYGB was significantly associated with vBMD deterioration in all skeletal sites except at the TH. RYGB also led to significant deterioration on bone quality. DXA underestimated LS and overestimated TH bone losses post-RYGB. In conclusion, RYGB was associated with significant vBMD loss, which makes screening of bone mass progression by three-dimensional technology a crucial clinical issue to prevent fracture risk and osteoporosis.

Bariatric Surgery and Osteoporosis

It has been increasingly acknowledged that bariatric surgery adversely affects skeletal health. After bariatric surgery, the extent of high-turnover bone loss is much greater than what would be expected in the absence of a severe skeletal insult. Patients also experience a significant deterioration in bone microarchitecture and strength. There is now a growing body of evidence that suggests an association between bariatric surgery and higher fracture risk. Although the mechanisms underlying the high-turnover bone loss and increase in fracture risk after bariatric surgery are not fully understood, many factors seem to be involved. The usual suspects are nutritional factors and mechanical unloading, and the roles of gut hormones, adipokines, and bone marrow adiposity should be investigated further. Roux-en-Y gastric bypass (RYGB) was once the most commonly performed bariatric procedure worldwide, but sleeve gastrectomy (SG) has now become the predominant bariatric procedure. Accumulating evidence suggests that RYGB is associated with a greater reduction in BMD, a greater increase in markers of bone turnover, and a higher risk of fracture than SG. These findings should be taken into consideration in determining the most appropriate bariatric procedure for patients, especially those at higher fracture risk. Before and after all bariatric procedures, sufficient calcium, vitamin D and protein intake, and adequate physical activity, are needed to counteract negative impacts on bone. There are no studies to date that have evaluated the effect of osteoporosis treatment on high-turnover bone loss after bariatric surgery. However, in patients with a diagnosis of osteoporosis, anti-resorptive agents may be considered.

Prebiotic to Improve Calcium Absorption in Postmenopausal Women After Gastric Bypass: A Randomized Controlled Trial

CONTEXT

The adverse skeletal effects of Roux-en-Y gastric bypass (RYGB) are partly caused by intestinal calcium absorption decline. Prebiotics, such as soluble corn fiber (SCF), augment colonic calcium absorption in healthy individuals.

OBJECTIVE

We tested the effects of SCF on fractional calcium absorption (FCA), biochemical parameters, and the fecal microbiome in a post-RYGB population.

METHODS

Randomized, double-blind, placebo-controlled trial of 20 postmenopausal women with history of RYGB a mean 5 years prior; a 2-month course of 20 g/day SCF or maltodextrin placebo was taken orally. The main outcome measure was between-group difference in absolute change in FCA (primary outcome) and was measured with a gold standard dual stable isotope method. Other measures included tolerability, adherence, serum calciotropic hormones and bone turnover markers, and fecal microbial composition via 16S rRNA gene sequencing.

RESULTS

Mean FCA ± SD at baseline was low at 5.5 ± 5.1%. Comparing SCF to placebo, there was no between-group difference in mean (95% CI) change in FCA (+3.4 [-6.7, +13.6]%), nor in calciotropic hormones or bone turnover markers. The SCF group had a wider variation in FCA change than placebo (SD 13.4% vs 7.0%). Those with greater change in microbial composition following SCF treatment had greater increase in FCA (r2 = 0.72, P = 0.05). SCF adherence was high, and gastrointestinal symptoms were similar between groups.

CONCLUSION

No between-group differences were observed in changes in FCA or calciotropic hormones, but wide CIs suggest a variable impact of SCF that may be due to the degree of gut microbiome alteration. Daily SCF consumption was well tolerated. Larger and longer-term studies are warranted.

Long-term complications after gastric bypass and sleeve gastrectomy: What information to give to patients and practitioners, and why?

Bariatric surgery is now recognized as the most effective treatment of morbid obesity, leading to durable weight loss and resolution of associated co-morbidities. Roux-en-Y gastric bypass and sleeve gastrectomy are the two most widely used operations today. However, potentially serious medical, surgical, and/or psychiatric complications can occur that raise questions regarding the benefits of this type of surgery. These complications can lead to surgical re-operations, iterative hospitalizations, severe nutritional deficiencies and psychological disorders. Indeed, death from suicide is said to be three times higher than in non-operated obese patients. These results are of concern, all the more because of the high prevalence of patients lost to follow-up (for various and multifactorial reasons) after bariatric surgery. However, better knowledge of post-surgical sequelae could improve the information provided to patients, the preoperative evaluation of the benefit/risk ratio, and, for patients undergoing surgery, the completeness and quality of follow-up as well as the detection and management of complications. The development of new strategies for postoperative follow-up such as telemedicine but also the mobilization of all the actors along the healthcare pathway can make inroads and warrant further study.

Fracture risk following bariatric surgery: a systematic review and meta-analysis

Bariatric surgery may negatively impact bone health. We aimed to compare fracture risk following bariatric surgery by type (malabsorptive, restrictive), or to non-surgical weight loss, or to controls with obesity. We systematically searched four databases from inception until October 2020. We included observational and interventional studies on adults. We screened articles and abstracted data in duplicate and independently and assessed the risk of bias. We conducted random-effects model meta-analyses (Review Manager v5.3), to calculate the relative risk of any or site-specific fracture (CRD42019128536). We identified four trials of unclear-to-high risk of bias and 15 observational studies of fair-to-good quality. Data on fracture risk following bariatric surgery compared to medical weight loss is scarce and limited by the small number of participants. In observational studies, at a mean/median post-operative follow-up > 2 years, the relative risk of any fracture was 45% (p < 0.001) and 61% (p = 0.04) higher following malabsorptive procedures compared to obese controls and restrictive procedures, respectively, with moderate to high heterogeneity. Site-specific relative fracture risk (hip and wrist) was one- to two-folds higher post malabsorptive procedures compared to obese controls or restrictive procedures. The risks of any and of site-specific fracture were not increased following restrictive procedures compared to obese controls. Fracture risk seems to increase following malabsorptive bariatric surgeries, at a mean/median follow-up > 2 years. The risk is not increased with restrictive surgeries. The available evidence has several limitations. A prospective and rigorous long-term follow-up of patients following bariatric surgery is needed for a better assessment of their fracture risk with aging.

Effect of Acupoint Catgut Embedding for Abdominally Obese Female with Strong Appetite: Mixed Analysis of a Randomized Clinical Trial

BACKGROUND

Abdominal obesity (AO) is not only a health issue, but also a serious impact on women's work and life. The article of acupoint catgut embedding (ACE) on AO has already been accepted to be published and showed significant effect. However, whether ACE is effective for abdominally obese female with strong appetite is still unclear.

METHODS

This is a mixed analysis of a multicenter, double-blind, randomized controlled trial.Which was conducted in China between July 2018 and March 2020 (n = 101), while with the supplementary samples (n = 22) between April 2020 and June 2022. According to the appetite and intervention methods, 123 abdominally obese female were divided into ACE group with strong appetite (n = 27) and moderate appetite (n = 31), control (non-acupoint catgut embedding) group with strong appetite (n = 37) and moderate appetite (n = 28). Four subgroups were given a 12-week actual intervention period and a 4-week follow-up. Waist circumference (WC), appetite, body weight and BMI were applied and assessed at baseline and after 6, 12 and 16 weeks.

RESULTS

In this study, the mean onset age of abdominal obesity in females was 25.27 (8.19) years old. The longer duration of AO, the lower the appetite in females (p<0.05). At 12 and 16 weeks, ACE group with strong appetite showed significant decrease in WC and appetite than control group with strong appetite (p<0.01). However, ACE group with moderate appetite showed no significant decrease than control group with moderate appetite in WC, appetite, body weight and BMI (p>0.05). At 12 and 16 weeks, there was no significant difference in appetite between the ACE groups (strong and moderate appetite)(p>0.05), while there was still a difference between the control groups (p<0.05).

CONCLUSION

Younger abdominally obese female had a stronger appetite. ACE own the remarkable therapeutic effects for younger abdominally obese female and showed the perfect effect on appetite-reduction.

Bariatric surgery and skeletal health: A narrative review and position statement for management by the European Calcified Tissue Society (ECTS)

CONTEXT

Numerous studies have demonstrated detrimental skeletal consequences following bariatric surgery.

METHODS

A working group of the European Calcified Tissue Society (ECTS) performed an updated review of existing literature on changes of bone turnover markers (BTMs), bone mineral density (BMD), and fracture risk following bariatric surgery and provided advice on management based on expert opinion.

LITERATURE REVIEW

Based on observational studies, bariatric surgery is associated with a 21-44% higher risk of all fractures. Fracture risk is time-dependent and increases approximately 3 years after bariatric surgery. The bariatric procedures that have a malabsorptive component (including Roux-en-Y Gastric bypass (RYGB) and biliopancreatic diversion (BPD)) have clearly been associated with the highest risk of fracture. The extent of high-turnover bone loss suggests a severe skeletal insult. This is associated with diminished bone strength and compromised microarchitecture. RYGB was the most performed bariatric procedure worldwide until very recently, when sleeve gastrectomy (SG) became more prominent. There is growing evidence that RYGB is associated with greater reduction in BMD, greater increase in BTMs, and higher risk of fractures compared with SG but RCTs on optimal management are still lacking.

EXPERT OPINION

In all patients, it is mandatory to treat vitamin D deficiency, to achieve adequate daily calcium and protein intake and to promote physical activity before and following bariatric surgery. In post-menopausal women and men older than 50 years, osteoporosis treatment would be reasonable in the presence of any of the following criteria: i) history of recent fragility fracture after 40 years of age, ii) BMD T-score ≤ -2 at hip or spine, iii) FRAX score with femoral neck BMD exceeding 20% for the 10-year major osteoporotic fracture probability or exceeding 3% for hip fracture. Zoledronate as first choice should be preferred due to intolerance of oral formulations and malabsorption. Zoledronate should be used with caution due to hypocemia risk. It is recommended to ensure adequate 25-OH vitamin D level and calcium supplementation before administering zoledronate.

CONCLUSIONS

The bariatric procedures that have a malabsorptive component have been associated with the highest turnover bone loss and risk of fracture. There is a knowledge gap on osteoporosis treatment in patients undergoing bariatric surgery. More research is necessary to direct and support guidelines.

Obesity and Bone: A Complex Relationship

There is a large literature on the relationship between obesity and bone. What we can conclude from this review is that the increase in body weight causes an increase in BMD, both for a mechanical effect and for the greater amount of estrogens present in the adipose tissue. Nevertheless, despite an apparent strengthening of the bone witnessed by the increased BMD, the risk of fracture is higher. The greater risk of fracture in the obese subject is due to various factors, which are carefully analyzed by the Authors. These factors can be divided into metabolic factors and increased risk of falls. Fractures have an atypical distribution in the obese, with a lower incidence of typical osteoporotic fractures, such as those of hip, spine and wrist, and an increase in fractures of the ankle, upper leg, and humerus. In children, the distribution is different, but it is not the same in obese and normal-weight children. Specifically, the fractures of the lower limb are much more frequent in obese children. Sarcopenic obesity plays an important role. The authors also review the available literature regarding the effects of high-fat diet, weight loss and bariatric surgery.

A comparison of changes in bone turnover markers after gastric bypass and sleeve gastrectomy, and their association with markers of interest

BACKGROUND

It is still debated whether differences in bone turnover markers (BTMs) exist between the 2 most popular bariatric surgery procedures (Roux-en-Y gastric bypass [RYGB] and sleeve gastrectomy [SG]).

OBJECTIVES

To compare changes in BTMs after RYGB and SG, and to investigate their association with predefined markers of interest.

SETTING

University hospital, Lille, France.

METHODS

An ancillary investigation of a prospective cohort was conducted. SG patients with severe obesity ≥40 years were matched one-to-one to RYGB patients for age, sex, body mass index (BMI), and menopausal status. BTMs, as well as predefined markers of interest, were measured at baseline, 12, and 24 months after bariatric surgery.

RESULTS

Sixty-four patients (66% women) had a mean (standard deviation [SD]) age of 49.6 years (5.1) and a mean (SD) BMI of 45.0 kg/m² (6.0). From baseline to 12 months, a significant increase in BTMs was observed in both groups (P < .001). Moreover, RYGB was associated with a greater increase in C-terminal telopeptide (β-CTX) and procollagen type 1 N-terminal propeptide (PINP) compared with SG (P < .0001). From 12 to 24 months, a significant decrease in BTMs was observed in both groups, but no significant differences were found between RYGB and SG. However, BTMs did not return to baseline levels. The changes in PINP and β-CTX at 12 months were independently associated with the type of surgical procedure, after adjusting for weight or each predefined marker of interest (all P < .0001).

CONCLUSION

RYGB was associated with a greater increase in BTMs than SG at 12 and 24 months.

Rates, Risks, and Time to Fracture in Patients Undergoing Laparoscopic Vertical Sleeve Gastrectomy versus Roux-en-Y Gastric Bypass

Objective

To assess the rates, risks, and time to fracture in patients undergoing laparoscopic vertical sleeve gastrectomy (VSG) versus those undergoing Roux-en-Y gastric bypass (RYGB).

Summary Background Data

Metabolic and bariatric surgery has been implicated in significant bone loss and may increase fracture risk. Preoperative patient characteristics that might impact fracture risk and the time to fractures have not been established. Furthermore, the patient characteristics that might impact fracture risk and the time to fractures by surgical approach are unknown.

Methods

This population-based retrospective cohort analysis used Humana claims data from January 1, 2007 to March 31, 2017, and included 4073 patients undergoing laparoscopic RYGB and VSG as a first surgical intervention for weight loss. The primary outcomes were the incidence of fractures (Humeral, Radial or Ulnar, Pelvic, Hip, and Vertebral) within 48 months after laparoscopic VSG versus RYGB and days to these fractures.

Results

An analysis of total fractures (odds ratio [OR] 0.53; 95% confidence interval [CI], 0.38-0.73), vertebral fractures (OR 0.61; 95% CI, 0.38-0.99), hip fractures (OR 0.36; 95% CI, 0.15-0.84), and humeral fractures (OR 0.44; 95% CI, 0.22-0.90) demonstrated a reduction in fracture risk in patients undergoing VSG versus RYGB. Furthermore, postmenopausal status was independently associated with increased odds of total fractures and hip fractures (OR 2.18; 95% CI, 1.06-4.50; OR 5.83; 95% CI, 1.16-29.27; respectively). Likewise, osteoporosis at the time of surgery was associated with increased odds of total fractures (OR 1.61; 95% CI, 1.09-2.37), vertebral fractures (OR 2.01; 95% CI, 1.19-3.39), and hip fractures (OR 2.38; 95% CI, 1.19-4.77). Except for a significantly decreased odds of vertebral fractures in osteoporotic patients undergoing VSG versus RYGB (OR 0.41; 95% CI, 0.18-0.95), osteoporotic or postmenopausal status at the time of surgery was not found to increase odds of fracture depending on surgical intervention. However, time to fracture (total) and for all site-specific fractures, except for pelvic fractures, was significantly reduced in postmenopausal women undergoing RYGB versus VSG. Time to fracture (total) and for all site-specific fractures except pelvic and radial or ulnar fractures was significantly reduced in osteoporotic patients undergoing RYGB versus VSG.

Conclusions and Relevance

Though bariatric surgery is associated with several health-related benefits, increased fracture risk is an important factor to discuss with patients undergoing bariatric surgery. Bariatric surgery strategy, RYGB versus VSG, carries a differential risk of fracture, with RYGB carrying a higher risk of fracture and decreased time to fracture. Furthermore, patients who are postmenopausal or osteoporotic at the time of surgery carry an increased risk of total fractures, independent of bariatric surgery strategy. Being mindful of patient-specific fracture risk after bariatric surgery may help anticipate, identify, and prevent fractures.

Increased Fracture Risk After Bariatric Surgery: a Case-Controlled Study with a Long-Term Follow-Up

Purpose

Bariatric surgeries are common procedures due to the high prevalence of obesity. This study aimed to investigate whether bariatric surgery increases fracture risk.

Material and Methods

It was a case-controlled study. Patients who underwent bariatric surgery during 2011 and 2012 were matched for age (± 5 years) and gender to patients on medical weight management during the same period with a ratio of 1:2. The index date was defined as the date of bariatric surgery for both groups. The subject’s electronic medical records were reviewed retrospectively to identify fractures documented by radiology during January 2020.

Results

Randomly selected 403 cases were matched to 806 controls with a median age of 36.0 years (IQR 14.0) and 37.0 years (IQR 14.0), respectively. Seventy per cent of the cohort were females. Eighty per cent received sleeve gastrectomy, and the remaining (17%) underwent gastric bypass. The mean duration of follow-up was 8.6 years. The fracture rate was higher in the surgical group as compared to the controls (9.4% vs 3.5%) with a crude odds ratio of 2.71 (95% CI 1.69–4.36). The median duration for time to fracture was 4.17 years for the surgical group and 6.09 years for controls (p-value = 0.097). The most common site of fractures was feet, followed by hands. Apart from a few wrist fractures, there was no typical osteoporotic sites fracture.

Conclusion

Subjects who underwent bariatric procedures had more non-typical osteoporotic site fractures affecting mainly feet and hands, and fractures tend to occur earlier as compared to controls.

Graphical abstract

Bone fragility in patients with diabetes mellitus: A consensus statement from the working group of the Italian Diabetes Society (SID), Italian Society of Endocrinology (SIE), Italian Society of Gerontology and Geriatrics (SIGG), Italian Society of Orthopaedics and Traumatology (SIOT)

Bone fragility is one of the possible complications of diabetes, either type 1 (T1D) or type 2 (T2D). Bone fragility can affect patients of different age and with different disease severity depending on type of diabetes, disease duration and the presence of other complications. Fracture risk assessment should be started at different stages in the natural history of the disease depending on the type of diabetes and other risk factors. The risk of fracture in T1D is higher than in T2D, imposing a much earlier screening and therapeutic intervention that should also take into account a patient's life expectancy, diabetes complications etc. The therapeutic armamentarium for T2D has been enriched with drugs that may influence bone metabolism, and clinicians should be aware of these effects. Considering the complexity of diabetes and osteoporosis and the range of variables that influence treatment choices in a given individual, the Working Group on bone fragility in patients with diabetes mellitus has identified and issued recommendations based on the variables that should guide screening of bone fragility and management of diabetes and bone fragility: (A)ge, (B)MD, (C)omplications, (D)uration of disease, & (F)ractures (ABCD&F). Consideration of these parameters may help clinicians identify the best time for screening, the appropriate glycaemic target and anti-osteoporosis drug for patients with diabetes at risk of or with bone fragility.

Roux-en-Y Gastric Bypass with Long Biliopancreatic Limb Compared to Single Anastomosis Sleeve Ileal (SASI) Bypass in Treatment of Morbid Obesity

PURPOSE

Bariatric surgery is the most effective treatment of morbid obesity. Bariatric procedures employ different mechanisms of action to induce weight loss. The present study aimed to compare single-anastomosis sleeve ileal (SASI) bypass and roux-en-Y gastric bypass RYGB with long biliopancreatic limb (BPL) in terms of weight loss, remission of comorbidities, complications, and nutritional status.

METHODS

This was a single-center cohort study on patients with morbid obesity who underwent RYGB with long BPL of 150 cm or SASI bypass. The main outcome measures were weight loss and improvement in comorbidities at 12 months, nutritional status, and complications.

RESULTS

The present study included 92 patients (59.8% females) of a mean age of 38.4 years and mean BMI of 42 kg/m². RYGB and SASI bypass were followed by a significant decrease in body mass index at 12 months and were comparable in terms of excess and total weight loss. Improvement in comorbidities after the two procedures was similar. The serum albumin levels showed a significant decline after RYGB, but not after SASI bypass. The postoperative serum iron levels were higher after SASI bypass than after RYGB. There was no significant difference in regard to complication rates (13% vs 4.3%, p = 0.27).

CONCLUSIONS

RYGB with long BPL and SASI bypass achieved satisfactory weight loss and improvement in comorbidities that were comparable among the two groups. Long BPL RYGB was followed by a significant decrease in serum albumin and iron levels at one year, which was not observed after SASI bypass.

Long-term Bone Loss and Deterioration of Microarchitecture After Gastric Bypass in African American and Latina Women

CONTEXT

The prevalence of obesity is burgeoning among African American and Latina women; however, few studies investigating the skeletal effects of bariatric surgery have focused on these groups.

OBJECTIVE

To investigate long-term skeletal changes following Roux-en-Y gastric bypass (RYGB) in African American and Latina women.

DESIGN

Four-year prospective cohort study.

PATIENTS

African American and Latina women presenting for RYGB (n = 17, mean age 44, body mass index 44 kg/m2) were followed annually for 4 years postoperatively.

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry (DXA) measured areal bone mineral density (aBMD) at the spine, hip, and forearm, and body composition. High-resolution peripheral quantitative computed tomography measured volumetric bone mineral density (vBMD) and microarchitecture. Individual trabecula segmentation-based morphological analysis assessed trabecular morphology and connectivity.

RESULTS

Baseline DXA Z-Scores were normal. Weight decreased ~30% at Year 1, then stabilized. Parathyroid hormone (PTH) increased by 50% and 25-hydroxyvitamin D was stable. By Year 4, aBMD had declined at all sites, most substantially in the hip. There was significant, progressive loss of cortical and trabecular vBMD, deterioration of microarchitecture, and increased cortical porosity at both the radius and tibia over 4 years. There was loss of trabecular plates, loss of axially aligned trabeculae, and decreased trabecular connectivity. Whole bone stiffness and failure load declined. Risk factors for bone loss included greater weight loss, rise in PTH, and older age.

CONCLUSIONS

African American and Latina women had substantial and progressive bone loss, deterioration of microarchitecture, and trabecular morphology following RYGB. Further studies are critical to understand the long-term skeletal consequences of bariatric surgery in this population.

Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density in Zucker Diabetic Fatty Rats: A Short-Term Comparative Study

BACKGROUND

While bariatric surgery could result in weight loss as well as glycaemia improvement, the short-term impact on bone health in a high glycemic environment following Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) remains intriguing.

OBJECTIVE

The aim of this study was to compare the short-term effects of RYGB and SG procedures on bone health in Zucker diabetic fatty (ZDFfa/fa) rats.

METHODS

Thirty age-matched male ZDFfa/fa rats were randomized into RYGB, SG, and sham groups after establishment of the diabetic model. Body weight, blood glucose, bone mineral density (BMD), the level of bone turnover markers (BTM), vitamin D, and serum calcium and phosphorus were measured 4 weeks after the operation.

RESULTS

The RYGB procedure brought about lower blood glucose, BMD, serum calcium and phosphorus levels, as well as a relatively higher bone turnover rate and 1,25(OH)2VD level, compared to the SG and sham groups, while the influences of the SG procedure were not significant. 25(OH)VD demonstrated no significant difference among the 3 groups.

CONCLUSIONS

Despite its excellent ability to provide short-term glycemic control, the RYGB procedure could led to more severe impairment of bone health compared to the SG procedure. Bone health should be procured after bariatric surgery, especially with the RYGB procedure. Early detection of BMD and BTM may help to avoid deterioration of bone.

Zoledronic acid for prevention of bone loss in patients receiving bariatric surgery

Purpose

Bariatric surgery is an effective treatment for severe obesity but causes substantial bone loss and increased risk of fractures. To date, there have been no studies examining whether pharmacologic treatments can prevent bone loss after bariatric surgery. We performed an exploratory study to examine the preliminary safety and efficacy of zoledronic acid (ZOL), a potent anti-resorptive bisphosphonate, to suppress bone turnover markers (BTM) and prevent declines in bone mineral density (BMD) after Roux-en-Y gastric bypass (RYGB) surgery.

Methods

We performed an open-label pilot study of pre-operative ZOL in postmenopausal women with obesity who were planning RYGB (n = 4). A single dose of zoledronic acid 5 mg was given intravenously prior to RYGB. Serum bone biochemistries including C-telopeptide (CTX) and procollagen type 1 N-terminal propeptide (P1NP) were measured at multiple timepoints throughout the 24-week study. BMD was also obtained at the spine and hip by dual-energy x-ray absorptiometry (DXA) and at the trabecular spine by quantitative computed tomography (QCT) at pre-operative baseline and 24 weeks. Results were compared against pre-operative baseline and against changes among RYGB historical controls (n = 10).

Results

At 2 weeks after RYGB, there was a nonsignificant trend for CTX and P1NP levels to be lower than baseline levels in the ZOL group. By 24 weeks after RYGB, however, participants who received ZOL had a significant increase in CTX above pre-operative baseline (+0.228 ± 0.117 ng/dL, p = 0.030) but this CTX rise was less than that observed in the controls (+0.601 ± 0.307 ng/dL, p = 0.042 between groups). Despite ZOL use, participants had significant areal BMD loss at the total hip as compared to pre-operative baseline (-4.2 ± 1.5%, p = 0.012) that was similar in magnitude to total hip BMD loss in the controls (-5.5 ± 3.9%, p = 0.005). There was a suggestion that the ZOL group might be protected against trabecular spine volumetric bone loss as compared to the control group (+4.8 ± 8.0% vs. -5.9 ± 7.0%, p = 0.075 between groups). Serum calcium, 25-hydroxyvitamin D, and parathyroid hormone did not change in either group. No hypocalcemia or serious adverse events were reported after ZOL.

Conclusion

In this proof of concept study, a single dose of ZOL prior to RYGB appeared to transiently mitigate but not fully prevent high bone turnover in the acute postoperative period. At 24 weeks after RYGB, our preliminary data suggest that ZOL was not sufficient to prevent bone loss at the hip, although it may preserve bone density at the trabecular spine. Further prospective, controlled studies are needed to confirm our findings and to identify the best strategies for preventing bone loss in bariatric patients receiving RYGB.

Bone Metabolism in Adolescents Undergoing Bariatric Surgery

PURPOSE

The prevalence of childhood obesity has increased over past decades with a concomitant increase in metabolic and bariatric surgery (MBS). While MBS in adults is associated with bone loss, only a few studies have examined the effect of MBS on the growing skeleton in adolescents.

METHODS

This mini-review summarizes available data on the effects of the most commonly performed MBS (sleeve gastrectomy and gastric bypass) on bone in adolescents. A literature review was performed using PubMed for English-language articles.

RESULTS

Dual-energy x-ray absorptiometry (DXA) measures of areal bone mineral density (aBMD) and BMD Z scores decreased following all MBS. Volumetric BMD (vBMD) by quantitative computed tomography (QCT) decreased at the lumbar spine while cortical vBMD of the distal radius and tibia increased over a year following sleeve gastrectomy (total vBMD did not change). Reductions in narrow neck and intertrochanteric cross-sectional area and cortical thickness were observed over this duration, and hip strength estimates were deleteriously impacted. Marrow adipose tissue (MAT) of the lumbar spine increased while MAT of the peripheral skeleton decreased a year following sleeve gastrectomy. The amount of weight loss and reductions in lean and fat mass correlated with bone loss at all sites, and with changes in bone microarchitecture at peripheral sites.

CONCLUSION

MBS in adolescents is associated with aBMD reductions, and increases in MAT of the axial skeleton, while sleeve gastrectomy is associated with an increase in cortical vBMD and decrease in MAT of the peripheral skeleton. No reductions have been reported in peripheral strength estimates.

Risk Factors for Kidney Stone Formation following Bariatric Surgery

Kidney stones are painful, common, and increasing in incidence. Obesity and bariatric surgery rates are also on the rise in the United States. Although bariatric surgery is associated with improvements in metabolic outcomes, malabsorptive bariatric surgery procedures are also associated with increased risk of kidney stones. Restrictive bariatric surgeries have not been associated with kidney-stone risk. Higher risk of kidney stones after malabsorptive procedures is associated with postsurgical changes in urine composition, including high urine oxalate, low urine citrate, and low urine volume. Certain dietary recommendations after surgery may help mitigate these urine changes and reduce risk of kidney stones. Understanding risk of kidney stones after surgery is essential to improving patient outcomes after bariatric surgery.

A scoping review of the phenomenon of osteoporosis in post bariatric surgical patients

BACKGROUND

Risk factors, preventive treatment, and increased prevalence of fragility fractures in post-bariatric surgical patients have been researched, however, little is known about how patients' perspectives of osteoporosis risk determine their commitment to bone health.

PURPOSE

The purpose of this review was to provide an overview and appraisal of the research regarding osteoporosis in post bariatric surgical patients, as well as to identify gaps in the literature in this area.

METHODS

Data bases searched included OVID Medline, CINAHL, and EMBASE which included ahead of print articles that had not yet been indexed. Relevant key words were used independently and in combination: "osteoporosis," "morbid obesity," and "bariatric surgery."

RESULTS

A total of 24 quantitative studies and 15 qualitative studies were retrieved for this review; none of the qualitative studies examined both osteoporosis and bariatric surgery.

CONCLUSION

The current trend in bariatric surgical patients regarding osteoporosis is to examine the degree of bone loss based on significant influences including extent of weight loss, years since surgery, type of procedure performed, and subject selection. Patient perceptions about osteoporosis risk after bariatric surgery were rarely addressed.

MANAGEMENT OF ENDOCRINE DISEASE: Bone complications of bariatric surgery: updates on sleeve gastrectomy, fractures, and interventions

Despite well recognized improvements in obesity-related comorbidities, increasing evidence implicates bariatric surgery in the onset of adverse skeletal health outcomes. The purpose of this review is to provide a focused update in three critical areas: (i) emergent data on sleeve gastrectomy and bone loss, (ii) evidence linking bariatric surgery to incident fracture, and (iii) intervention strategies designed to mitigate surgical bone loss. Better understanding of these issues will inform our treatment of skeletal health for patients planning bariatric surgery.

Bone Density and Trabecular Morphology at Least 10 Years After Gastric Bypass and Gastric Banding

Roux-en-Y gastric bypass (RYGB) instigates high-turnover bone loss in the initial 5 years after surgery, whereas skeletal changes after adjustable gastric banding (AGB) are less pronounced. Long-term skeletal data are scarce, and the mechanisms of bone loss remain unclear. We sought to examine bone density and microarchitecture in RYGB and AGB patients a decade after surgery and to determine whether prior published reports of bone loss represent an appropriate adaptation to new postsurgical weight. In this cross-sectional study, 25 RYGB and 25 AGB subjects who had bariatric surgery ≥10 years ago were matched 1:1 with nonsurgical controls for age, sex, and current body mass index (BMI). We obtained bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), volumetric BMD and microarchitecture by high-resolution peripheral quantitative computed tomography (HR-pQCT), trabecular morphology by individual trabecular segmentation, and metabolic bone laboratory results. As compared with BMI-matched controls, RYGB subjects had significantly lower hip BMD, and lower total volumetric BMD at the distal radius and tibia. Substantial deficits in cortical and trabecular microarchitecture were observed in the RYGB group compared to controls, with reduced trabecular plate bone volume fraction and estimated failure load at both the radius and tibia, respectively. Bone turnover markers CTX and P1NP were 99% and 77% higher in the RYGB group than controls, respectively, with no differences in serum calcium, 25-hydroxyvitamin D, or parathyroid hormone. In contrast, the AGB group did not differ from their BMI-matched controls in any measured bone density, microarchitecture, or laboratory parameter. Thus, RYGB, but not AGB, is associated with lower than expected hip and peripheral BMD for the new weight setpoint, as well as deleterious changes in bone microarchitecture. These findings suggest that pathophysiologic processes other than mechanical unloading or secondary hyperparathyroidism contribute to bone loss after RYGB, and have important clinical implications for the long-term care of RYGB patients. © 2020 American Society for Bone and Mineral Research.

Soft tissue variations influence HR-pQCT density measurements in a spatially dependent manner

OBJECTIVE

Significant weight loss following treatments for obesity undermines bone metabolism and increases bone turnover and fracture incidence. High resolution peripheral quantitative computed tomography (HR-pQCT) is widely used in skeletal heath assessment research to provide noninvasive bone parameter measurement (e.g. volumetric bone mineral density (vBMD)) with minimal radiation exposure. However, variation in body composition among study groups or longitudinal variations within individuals undergoing significant weight change will generate artifacts and errors in HR-pQCT data. The purpose of this study is to determine the influence of these artifacts on the measurement of vBMD.

METHODS

We designed a custom-made hydroxyapatite (HA)-polymer phantom surrounded by layers of reusable gel pack and hydrogenated fat to mimic the distal tibia and the surrounding lean and fat tissue. Four different thicknesses of fat were used to mimic the soft tissue of increasingly overweight individuals. We then evaluated how a change in soft tissue thickness influenced image quality and vBMD quantification within total, trabecular, and cortical bone compartments. Based on these data, we applied a data correction to previously acquired clinical data in a cohort of gastric bypass patients.

RESULTS

In the phantom measurements, total, trabecular, and cortical vBMD increased as soft tissue thickness decreased. The impact of soft tissue thickness on vBMD varied by anatomic quadrant. When applying the soft tissue data correction to a set of clinical data, we found that soft tissue reduction following bariatric surgery can lead to a clinically significant underestimation of bone loss in longitudinal data, and that the effect is most severe in the cortical compartment.

CONCLUSION

HR-pQCT-based vBMD measurement accuracy is influenced by soft tissue thickness and is spatially inhomogeneous. Our results suggest that variations in soft tissue thickness must be considered in HR-pQCT studies, particularly in studies enrolling cohorts with differing body composition or in studies of longitudinal weight change.

Gastric Bypass But Not Sleeve Gastrectomy Increases Risk of Major Osteoporotic Fracture: French Population-Based Cohort Study

The objective of this work was to investigate the risk of major osteoporotic fracture (MOF; hip, proximal humerus, wrist and distal forearm, and clinical spine) in bariatric surgery patients versus matched controls. Bariatric surgery is associated with an increase in fracture risk. However, it remains unclear whether the same degree of fracture risk is associated with sleeve gastrectomy, which has recently surpassed gastric bypass. Records from the French National Inpatient database were used from 2008 to 2018. Bariatric surgery patients, aged 40 to 65 years, with BMI ≥40 kg/m² , hospitalized between January 1, 2010 and December 31, 2014, were matched to one control (1:1) by age, sex, Charlson comorbidity index, year of inclusion, and class of obesity (40 to 49.9 kg/m² versus ≥50 kg/m² ). We performed a Cox regression analysis to assess the association between the risk of any MOF and, respectively, (i) bariatric surgery (yes/no) and (ii) type of surgical procedure (gastric bypass, gastric banding, vertical banded gastroplasty, and sleeve gastrectomy) versus no surgery. A total of 81,984 patients were included in the study (40,992 in the bariatric surgery group, and 40,992 matched controls). There were 585 MOFs in the surgical group (2.30 cases per 1000 patient-year [PY]) and 416 MOFs in the matched controls (1.93 cases per 1000 PY). The risk of MOF was significantly higher in the surgical group (hazard ratio [HR] 1.22; 95% CI, 1.08-1.39). We observed an increase in risk of MOF for gastric bypass only (HR 1.70; 95% CI, 1.46-1.98) compared with the matched controls. In patients aged 40 to 65 years, gastric bypass but not sleeve gastrectomy or the other procedures increased risk of major osteoporotic fractures. © 2020 American Society for Bone and Mineral Research.

Fat and bone: the multiperspective analysis of a close relationship

The study of bone has for many years been focused on the study of its mineralized component, and one of the main objects of study as radiology developed as a medical specialty. The assessment has until recently been almost limited to its role as principal component of the scaffolding of the human body. Bone is a very active tissue, in continuous cross-talk with other organs and systems, with functions that are endocrine and paracrine and that have an important involvement in metabolism, ageing and health in general. Bone is also the continent for the bone marrow, in the form of "yellow marrow" (mainly adipocytes) or "red marrow" (hematopoietic cells and adipocytes). Recently, numerous studies have focused on these adipocytes contained in the bone marrow, often referred to as marrow adipose tissue (MAT). Bone marrow adipocytes do not only work as storage tissue, but are also endocrine and paracrine cells, with the potential to contribute to local bone homeostasis and systemic metabolism. Many metabolic disorders (osteoporosis, obesity, diabetes) have a complex and still not well-established relationship with MAT. The development of imaging methods, in particular the development of cross-sectional imaging has helped us to understand how much more laid beyond our classical way to look at bone. The impact on the mineralized component of bone in some cases (e.g., osteoporosis) is well-established, and has been extensively analyzed and quantified through different radiological methods. The application of advanced magnetic resonance techniques has unlocked the possibility to access the detailed study, characterization and quantification of the bone marrow components in a non-invasive way. In this review, we will address what is the evidence on the physiological role of MAT in normal skeletal health (interaction with the other bone components), during the process of normal aging and in the context of some metabolic disorders, highlighting the role that imaging methods play in helping with quantification and diagnosis.

Fracture Risk After Roux-en-Y Gastric Bypass vs Adjustable Gastric Banding Among Medicare Beneficiaries

Importance

Roux-en-Y gastric bypass (RYGB) is associated with significant bone loss and may increase fracture risk, whereas substantial bone loss and increased fracture risk have not been reported after adjustable gastric banding (AGB). Previous studies have had little representation of patients aged 65 years or older, and it is currently unknown how age modifies fracture risk.

Objective

To compare fracture risk after RYGB and AGB procedures in a large, nationally representative cohort enriched for older adults.

Design, Setting, and Participants

This population-based retrospective cohort analysis used Medicare claims data from January 1, 2006, to December 31, 2014, from 42 345 severely obese adults, of whom 29 624 received RYGB and 12 721 received AGB. Data analysis was performed from April 2017 to November 2018.

Main Outcomes and Measures

The primary outcome was incident nonvertebral (ie, wrist, humerus, pelvis, and hip) fractures after RYGB and AGB surgery defined using a combination of International Classification of Diseases, Ninth Edition and Current Procedural Terminology 4 codes.

Results

Of 42 345 participants, 33 254 (78.5%) were women. With a mean (SD) age of 51 (12) years, recipients of RYGB were younger than AGB recipients (55 [12] years). Both groups had similar comorbidities, medication use, and health care utilization in the 365 days before surgery. Over a mean (SD) follow-up of 3.5 (2.1) years, 658 nonvertebral fractures were documented. The fracture incidence rate was 6.6 (95% CI, 6.0-7.2) after RYGB and 4.6 (95% CI, 3.9-5.3) after AGB, which translated to a hazard ratio (HR) of 1.73 (95% CI, 1.45-2.08) after multivariable adjustment. Site-specific analyses demonstrated an increased fracture risk at the hip (HR, 2.81; 95% CI, 1.82-4.49), wrist (HR, 1.70; 95% CI, 1.33-2.14), and pelvis (HR, 1.48; 95% CI, 1.08-2.07) among RYGB recipients. No significant interactions of fracture risk with age, sex, diabetes status, or race were found. In particular, adults 65 years and older showed similar patterns of fracture risk to younger adults. Sensitivity analyses using propensity score matching showed similar results (nonvertebral fracture: HR 1.75; 95% CI, 1.22-2.52).

Conclusions and Relevance

This study of a large, US population-based cohort including a substantial population of older adults found a 73% increased risk of nonvertebral fracture after RYGB compared with AGB, including increased risk of hip, wrist, and pelvis fractures. Fracture risk was consistently increased among RYGB patients vs AGB across different subgroups, and to a similar degree among older and younger adults. Increased fracture risk appears to be an important unintended consequence of RYGB.

Glycocholic acid and butyrate synergistically increase vitamin D-induced calcium uptake in Caco-2 intestinal epithelial cell monolayers

Background

Roux-en-Y gastric bypass (RYGB) substantially decreases intestinal calcium absorption and may eventually lead to bone resorption. This is likely a consequence of bile diversion from the alimentary limb, as the presence of bile seems necessary for vitamin D-mediated calcium uptake. We recently suggested that the mediating mechanism may be a down-regulation of the vitamin D co-activator heat-shock protein (Hsp)90β. Recent evidence suggests that vitamin D may have effects on both active and passive calcium absorption.

Aim

To identify mechanisms in vitro that may be responsible for the decreased calcium absorption after RYGB. We hypothesized that bile, alone or in concert with nutritional compounds, could be of importance.

Material & methods

Caco-2 cells were grown confluent on semi-permeable membranes in a double-chamber setup to mimic small intestinal mucosa. The effect of bile acids chenodeoxycholic, lithocholic, glycocholic and taurocholic acid, with and without the addition of the fatty-acid butyrate, were tested for their effects on Hsp90β expression and active and passive calcium-flux monitored using radioactive ⁴⁵Ca.

Results

We initially found that whole human bile, but only together with the fatty acid butyrate, potently induced Hsp90β expression. In line with this, a single bile acid, e.g. glycocholic acid (GCA), in combination with butyrate, increased Hsp90β expression (40 ± 13% vs. GCA, butyrate or vehicle alone; p < 0,001; n = 14–25). Further, this combination together with vitamin D increased the passive gradient-driven flux of calcium, compared to stimulation with vitamin D alone or in combination with either GCA or butyrate (880 ± 217% vs. vitamin D and GCA or butyrate, or vitamin D only; p = 0,01–0.006; n = 5–11). Surprisingly, this combination had no effect on active calcium transport in the absence of calcium gradient.

Conclusion

The combination of GCA and butyrate increased gradient-driven calcium uptake up to 9-fold in Caco-2 intestinal epithelial cells, but had no effect on active calcium absorption. This effect was mediated via the vitamin D receptor co-activator Hsp90β.

The curious fate of bone following bariatric surgery: bone effects of sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) in mice

BACKGROUND

Bone loss and increased fracture risk following bariatric surgery has been reported. We investigated whether the two most commonly performed surgeries, sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB), lead to bone loss. In addition, we examined whether fortification of the diet with calcium citrate prevents bone loss.

METHODS

We used mouse models for SG and RYGB and compared bone loss with a group of sham mice with similar weight loss. All groups were switched at the time of surgery to a low-fat diet (LFD). We also examined whether fortification of the diet with calcium citrate and vitamin D was able to prevent bone loss.

RESULTS

At 2 weeks we observed no major bone effects. However, at 8 weeks, both trabecular and cortical bone were lost to the same extent after SG and RYGB, despite increased calcium absorption and adequate serum levels of calcium, vitamin D, and parathyroid hormone (PTH). Diet fortification with calcium citrate and vitamin D was able to partially prevent bone loss.

CONCLUSIONS

Both SG and RYGB lead to excess bone loss, despite intestinal adaptations to increase calcium absorption. Fortifying the diet with calcium citrate and vitamin D partly prevented the observed bone loss. This finding emphasizes the importance of nutritional support strategies after bariatric surgery, but also affirms that the exact mechanisms leading to bone loss after bariatric surgery remain elusive and thus warrant further research.

Association of Bariatric Surgery With Risk of Fracture in Patients With Severe Obesity

IMPORTANCE

Given the complex relationship between body mass index, body composition, and bone density and the correlative nature of the studies that have established the prevailing notion that higher body mass indices may be protective against osteopenia and osteoporosis and, therefore, fracture, the absolute risk of fracture in patients with severe obesity who undergo either Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) compared with those who do not undergo bariatric surgery is unknown.

OBJECTIVE

To assess the rates of fractures associated with obesity and compare rates between those who do not undergo bariatric surgery, those who undergo RYGB, and those who undergo SG.

DESIGN, SETTING, AND PARTICIPANTS

In this retrospective multicenter cohort study of Medicare Standard Analytic Files derived from Medicare parts A and B records from January 2004 to December 2014, patients classified as eligible for bariatric surgery using the US Centers of Medicare & Medicaid criteria who either did not undergo bariatric surgery or underwent RYGB or SG were exactly matched in a 1:1 fashion based on their age, sex, Elixhauser Comorbidity Index, hypertension, smoking status, nonalcoholic fatty liver disease, hyperlipidemia, type 2 diabetes, osteoporosis, osteoarthritis, and obstructive sleep apnea status. Data were analyzed from November to December 2019.

EXPOSURES

RYGB or SG.

MAIN OUTCOMES AND MEASURES

The primary outcome measured in this study was the odds of fracture overall based on exposure to bariatric surgery. Secondary outcomes included the odds of type of fracture (humerus, radius or ulna, pelvis, hip, vertebrae, and total fractures) based on exposure to bariatric surgery.

RESULTS

A total of 49 113 patients were included and were equally made up of 16 371 bariatric surgery-eligible patients who did not undergo weight loss surgery, 16 371 patients who had undergone RYGB, and 16 371 patients who had undergone SG. Each group consisted of an equal number of 4109 men (25.1%) and 12 262 women (74.9%) and had an equal distribution of ages, with 11 780 patients (72.0%) 64 years or younger, 4230 (25.8%) aged 65 to 69 years, 346 (2.1%) aged 70 to 74 years, and 15 (0.1%) aged 75 to 79 years. Patients undergoing RYGB were found to have no significant difference in odds of fractures compared with bariatric surgery-eligible patients who did not undergo surgery. Patients undergoing undergone SG were found to have decreased odds of fractures of the humerus (odds ratio [OR], 0.57; 95% CI, 0.45-0.73), radius or ulna (OR, 0.38; 95% CI, 0.25-0.58), hip (OR, 0.49; 95% CI, 0.33-0.74), pelvis (OR, 0.34; 95% CI, 0.18-0.64), vertebrae (OR, 0.60; 95% CI, 0.48-0.74), or fractures in general (OR, 0.53; 95% CI, 0.46-0.62). Compared with patients undergoing SG, patients undergoing RYGB had a significantly greater risk of total fractures (OR, 1.79; 95% CI, 1.55-2.06) and humeral fractures (OR, 1.60; 95% CI, 1.24-2.07).

CONCLUSIONS AND RELEVANCE

In this cohort study, bariatric surgery was associated with a reduced risk of fracture in bariatric surgery-eligible patients. Sleeve gastrectomy might be the best option for weight loss in patients in which fractures could be a concern, as RYGB may be associated with an increased fracture risk compared with SG.

The Skeletal Consequences of Bariatric Surgery

PURPOSE OF REVIEW

This review outlines the recent findings regarding the impact of bariatric surgery on bone. It explores potential mechanisms for skeletal changes following bariatric surgery and strategies for management.

RECENT FINDINGS

Bone loss following bariatric surgery is multifactorial. Probable mechanisms include skeletal unloading, abnormalities in calciotropic hormones, and changes in gut hormones. Skeletal changes that occur after bariatric surgery are specific to procedure type and persist for several years post-operatively. Studies suggest that while bone loss begins early, fracture risk may be increased later in the post-operative course, particularly after Roux-en-Y gastric bypass (RYGB). Further research is needed to assess the extent to which skeletal changes following bariatric surgery result in fragility. Current management should be geared toward prevention of bone loss, correction of nutritional deficiencies, and incorporation of weight bearing exercise. Pharmacologic treatment should be considered for high-risk patients.

New Developments in Fracture Risk Assessment for Current Osteoporosis Reports

PURPOSE OF REVIEW

Identifying individuals at high fracture risk can be used to target those likely to derive the greatest benefit from treatment. This narrative review examines recent developments in using specific risk factors used to assess fracture risk, with a focus on publications in the last 3 years.

RECENT FINDINGS

There is expanding evidence for the recognition of individual clinical risk factors and clinical use of composite scores in the general population. Unfortunately, enthusiasm is dampened by three pragmatic randomized trials that raise questions about the effectiveness of widespread population screening using clinical fracture prediction tools given suboptimal participation and adherence. There have been refinements in risk assessment in special populations: men, patients with diabetes, and secondary causes of osteoporosis. New evidence supports the value of vertebral fracture assessment (VFA), high resolution peripheral quantitative CT (HR-pQCT), opportunistic screening using CT, skeletal strength assessment with finite element analysis (FEA), and trabecular bone score (TBS). The last 3 years have seen important developments in the area of fracture risk assessment, both in the research setting and translation to clinical practice. The next challenge will be incorporating these advances into routine work flows that can improve the identification of high risk individuals at the population level and meaningfully impact the ongoing crisis in osteoporosis management.

Bone outcomes following sleeve gastrectomy in adolescents and young adults with obesity versus non-surgical controls

BACKGROUND

Sleeve gastrectomy is the most commonly performed weight loss surgery in adolescents with moderate-to-severe obesity. While studies in adults have reported on the deleterious effects of gastric bypass surgery on bone structure and strength estimates, data are lacking for the impact of sleeve gastrectomy on these measures in adolescents.

OBJECTIVE

To evaluate the impact of sleeve gastrectomy on bone outcomes in adolescents and young adults over 12 months using dual energy X-ray absorptiometry (DXA) and high resolution peripheral quantitative computed tomography (HRpQCT).

PARTICIPANTS AND METHODS

We enrolled 44 youth 14-22 years old with moderate to severe obesity; 22 underwent sleeve gastrectomy and 22 were followed without surgery (16 females and 6 males in each group). At baseline and 12 months, DXA was used to assess areal bone mineral density (aBMD), HRpQCT of the distal radius and tibia was performed to assess bone geometry, microarchitecture and volumetric BMD (vBMD), and finite element analysis to assess strength estimates (stiffness and failure load). These analyses were adjusted for age, sex, race and the bone measure at baseline. Fasting blood samples were assessed for calcium, phosphorus, and 25(OH) vitamin D (25OHD) levels.

RESULTS

Over 12-months, the surgical group lost 27.2% of body weight compared to 0.1% in the non-surgical (control) group. Groups did not differ for changes in 25OHD levels (p = 0.186). Compared to controls, the surgical group had reductions in femoral neck and total hip aBMD Z-scores (p ≤ 0.0006). At the distal tibia, compared to controls, the surgical group had reductions in cortical area and thickness and trabecular number, and increases in trabecular area and separation (p ≤ 0.026). At the distal radius, the surgical group had greater reductions in trabecular vBMD, than controls (p = 0.010). The surgical group had an increase in cortical vBMD at both sites (p ≤ 0.040), possibly from a decrease in cortical porosity (p ≤ 0.024). Most, but not all, differences were attenuated after adjusting for 12-month change in BMI. Groups did not differ for changes in strength estimates over time, except that increases in tibial stiffness were lower in the surgical group (p = 0.044) after adjusting for 12-month change in BMI.

CONCLUSIONS

Over 12 months, weight loss associated with sleeve gastrectomy in adolescents had negative effects on areal BMD and certain HRpQCT parameters. However, bone strength estimates remained stable, possibly because of a simultaneous decrease in cortical porosity and increase in cortical volumetric BMD. Additional research is necessary to determine the relative contribution(s) of weight loss and the metabolic effects of surgery on bone outcomes, and whether the observed effects on bone stabilize or progress over time.

Nutritional Risks in Adolescents After Bariatric Surgery

BACKGROUND & AIMS

Little is known about prevalence and risk factors for nutritional deficiencies in adolescents after metabolic bariatric surgery. We performed a 5-year prospective cohort study of these.

METHODS

Adolescents who had Roux-en-Y gastric bypass (RYGB, n = 161) or vertical sleeve gastrectomy (VSG, n = 67) were enrolled at 5 tertiary-care centers from March 2007 through February 2012. The final analysis cohort included 226 participants (161 who had RYGB and 65 who had VSG). We measured serum levels of ferritin; red blood cell folate; vitamins A, D, B₁, B₁₂; and parathyroid hormone at baseline and annually for 5 years. General linear mixed models were used to examine changes over time and identify factors associated with nutritional deficiencies.

RESULTS

The participants were 75% female and 72% white, with a mean age of 16.5 ± 1.6 years and mean body mass index of 52.7 ± 9.4 kg/m² at surgery. Mean body mass index decreased 23% at 5 years, and did not differ significantly between procedures. After RYGB, but not VSG, serum concentrations of vitamin B₁₂ significantly decreased whereas serum levels of transferrin and parathyroid hormone increased. Ferritin levels decreased significantly after both procedures. Hypo-ferritinemia was observed in 2.5% of patients before RYGB and 71% at 5 y after RYGB (P < .0001), and 11% of patients before VSG and 45% 5 y after VSG (P = .002). No significant changes in serum levels of folate or vitamins A, B₁, or D were found between baseline and 5 y after either procedure. By 5 y, 59% of RYGB and 27% of VSG recipients had 2 or more nutritional deficiencies. Risk factors associated with specific deficiencies included surgery type, female sex, black race, supplementation intake, weight regain, and for females, pregnancy.

CONCLUSIONS

In a prospective study of adolescents who underwent RYGB or VSG, we observed nutritional deficiencies by 5 y after the procedures-particularly in iron and B₁₂ after RYGB. Ongoing nutrient monitoring and supplementation are recommended for all patients, but surgery type, supplementation intake, sex, and race might affect risk. (Clinical trial registration: Adolescent Bariatrics: Assessing Health Benefits and Risk [also known as Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS)], NCT00474318.).

Fracture risk after three bariatric surgery procedures in Swedish obese subjects: up to 26 years follow-up of a controlled intervention study

BACKGROUND

Previous studies have reported an increased fracture risk after bariatric surgery.

OBJECTIVE

To investigate the association between different bariatric surgery procedures and fracture risk.

METHODS

Incidence rates and hazard ratios for fracture events were analysed in the Swedish Obese Subjects study; an ongoing, nonrandomized, prospective, controlled intervention study. Hazard ratios were adjusted for risk factors for osteoporosis and year of inclusion. Information on fracture events were captured from the Swedish National Patient Register. The current analysis includes 2007 patients treated with bariatric surgery (13.3% gastric bypass, 18.7% gastric banding, and 68.0% vertical banded gastroplasty) and 2040 control patients with obesity matched on group level based on 18 variables. Median follow-up was between 15.1 and 17.9 years for the different treatment groups.

RESULTS

During follow-up, the highest incidence rate for first-time fracture was observed in the gastric bypass group (22.9 per 1000 person-years). The corresponding incidence rates were 10.4, 10.7 and 9.3 per 1000 person-years for the vertical banded gastroplasty, gastric banding and control groups, respectively. The risk of fracture was increased in the gastric bypass group compared with the control group (adjusted hazard ratio [adjHR] 2.58; 95% confidence interval [CI] 2.02-3.31; P < 0.001), the gastric banding group (adjHR 1.99; 95%CI 1.41-2.82; P < 0.001), and the vertical banded gastroplasty group (adjHR 2.15; 95% CI 1.66-2.79; P < 0.001).

CONCLUSIONS

The risk of fracture is increased after gastric bypass surgery. Our findings highlight the need for long-term follow-up of bone health for patients undergoing this treatment.

Bone Health in Patients with Type 2 Diabetes Treated by Roux-En-Y Gastric Bypass and the Role of Diabetes Remission

BACKGROUND

Roux-en-Y gastric bypass (RYGB) has been associated with negative effects on bone. Whether this association is affected by pre-surgical type 2 diabetes (T2D) and surgically induced diabetes remission is unknown.

METHODS

In this cross-sectional, matched cohort study 6 years after RYGB, we investigated bone health in 96 individuals with body mass index (BMI) > 35 kg/m² and T2D (stratified on current diabetes status) treated by RYGB 6 years earlier compared with 49 non-operated individuals with T2D matched with respect to sex, age, and current BMI. Main outcome measures were areal and volumetric bone mineral density (aBMD and vBMD), bone turnover, and odds ratio of osteoporosis/osteopenia.

RESULTS

The RYGB group had lower hip (0.916 vs 1.010 g/cm², p < 0.001), forearm (0.497 g/cm² vs 0.554 g/cm², p < 0.001) aBMD, (269.63 mg/cm³ vs 306.07 mg/cm³, p < 0.001) tibial, and radial (238.57 mg/cm³ vs 278.14 mg/cm³, p < 0.0001) vBMD than the control group. Relative to the control group, c-terminal cross-linked telopeptide, procollagen type I amino-terminal propeptide, and osteocalcin were 75%, 41%, and 72% higher in the RYGB group, respectively (all p < 0.001). Odds ratio for osteopenia/osteoporosis in operated individuals was 2.21 (95% CI 1.06; 4.79, p = 0.05). Overall, stratified analysis on current diabetes status did not alter these outcomes.

CONCLUSIONS

Individuals with T2D treated by RYGB, compared to individuals with T2D of similar age and body composition not treated by RYGB, have lower BMD, lower bone strength, and increased levels of several bone turnover markers. Bone health was not associated with current diabetes status in the RYGB group.