Gastric banding induces negative bone remodelling in the absence of secondary hyperparathyroidism: potential role of serum C telopeptides for follow-up

Trends in insulin-like growth factor-1 levels after bariatric surgery: a systematic review and meta-analysis

According to studies, there are many inconsistencies in how IGF-1 levels change after bariatric surgery compared to before surgery, as well as its effects. These discrepancies can be attributed to various factors such as age, body mass index (BMI), and duration of intervention. Therefore, the aim of this study was to evaluate the level of insulin-like growth factor-1 (IGF-1) after bariatric surgery. A systematic review and meta-analysis based on the PRISMA guidelines was conducted from inception until 2021. From 1871 articles initially selected, 24 studies with 28 treatment arms met the eligible criteria and were included. Pooled findings from the random-effects model indicated that IGF-1 levels increased significantly [weighted mean difference (WMD) = 8.84 ng/ml; 95% confidence interval (CI) 0.30-17.39; p = 0.043] after bariatric surgery compared to before surgery. No significant heterogeneity was noted among the studies (Cochran Q test, p = 0.90, I² = 0.0%). In subgroup analysis, bariatric surgery significantly increased IGF-1 levels at age <40 years but not at age ≤40 years. Bariatric surgery is capable of increasing the IGF-1 levels compared to the period prior to surgery but with a modest clinical magnitude.

Bone Response to Weight Loss Following Bariatric Surgery

Obesity is a global health challenge that warrants effective treatments to avoid its multiple comorbidities. Bariatric surgery, a cornerstone treatment to control bodyweight excess and relieve the health-related burdens of obesity, can promote accelerated bone loss and affect skeletal strength, particularly after malabsorptive and mixed surgical procedures, and probably after restrictive surgeries. The increase in bone resorption markers occurs early and persist for up to 12 months or longer after bariatric surgery, while bone formation markers increase but to a lesser extent, suggesting a potential uncoupling process between resorption and formation. The skeletal response to bariatric surgery, as investigated by dual-energy X-ray absorptiometry (DXA), has shown significant loss in bone mineral density (BMD) at the hip with less consistent results for the lumbar spine. Supporting DXA studies, analyses by high-resolution peripheral quantitative computed tomography (HR-pQCT) showed lower cortical density and thickness, higher cortical porosity, and lower trabecular density and number for up to 5 years after bariatric surgery. These alterations translate into an increased risk of fall injury, which contributes to increase the fracture risk in patients who have been subjected to bariatric surgery procedures. As bone deterioration continues for years following bariatric surgery, the fracture risk does not seem to be dependent on acute weight loss but, rather, is a chronic condition with an increasing impact over time. Among the post-bariatric surgery mechanisms that have been claimed to act globally on bone health, there is evidence that micro- and macro-nutrient malabsorptive factors, mechanical unloading and changes in molecules partaking in the crosstalk between adipose tissue, bone and muscle may play a determining role. Given these circumstances, it is conceivable that bone health should be adequately investigated in candidates to bariatric surgery through bone-specific work-up and dedicated postsurgical follow-up. Specific protocols of nutrients supplementation, motor activity, structured rehabilitative programs and, when needed, targeted therapeutic strategies should be deemed as an integral part of post-bariatric surgery clinical support.

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.

Tibial Bone Quality in Former Bariatric Surgery Patients with Osteoarthritis

Downstream effects of bariatric weight-loss surgery have been associated with bone resorption, potentially jeopardizing total knee arthroplasty (TKA) implant fixation/ingrowth.

PURPOSE

This case-control study sought to determine if TKA patients with history of bariatric surgery exhibit altered microanatomy of subchondral bone quality in the tibial plateau compared to controls.

MATERIALS AND METHODS

With IRB approval, 41 bone samples were evaluated from 12 former bariatric surgery patients and 10 sex-, age-, weight-, height-, and BMI-matched controls. Patient-Reported Outcomes Measurement Information System (PROMIS) surveys were completed prior to TKA. Tibial plateau osteochondral tissues were recovered during the TKA procedure, and samples from the medial and lateral plateaus were dissected into 1 × 2 cm sections, scanned using microcomputed tomography (µCT), and plastic-embedded for histologic sectioning/staining of undecalcified bone. Paired t tests with Bonferroni correction were performed to assess group differences.

RESULTS

Female bariatric surgery patients had reduced osteoid/total area and greater osteoclast number asymmetry than female controls (p < 0.03). No differences were noted in µCT or histologic bone parameters between bariatric and control patients when the sexes were combined. Bariatric patients self-reported worse preoperative PROMIS pain interference and physical function scores than controls (p < 0.04).

CONCLUSIONS

Similarities of subchondral bone between former bariatric surgery patients and matched controls indicate OA disease progression dominates the bone landscape in both patient groups.

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.

Changes in Bone Mineral Density After Weight Loss Due to Metabolic Surgery or Lifestyle Intervention in Obese Patients

PURPOSE

Metabolic surgery and lifestyle intervention are two common methods used to treat obesity, but the effects of weight loss on bone mineral density (BMD) remain controversial. Our aim was to evaluate changes in BMD of the total hip, femoral neck, and lumbar spine after weight loss caused by metabolic surgery or lifestyle intervention.

MATERIALS AND METHODS

We searched PubMed, Web of Science, and the Cochrane Library to identify relevant studies published before 5 August 2020. The primary outcomes, including the BMD of the total hip, femoral neck, and lumbar spine before and 12 months after metabolic surgery or lifestyle intervention, were extracted.

RESULTS

A total of 19 studies with 1095 participants with obesity were included. Among them, 603 participants with obesity accepted metabolic surgery, while 492 accepted lifestyle intervention. At 12 months after weight loss, the BMD of the total hip decreased significantly in obese patients (mean difference [MD] = 0.06 g/cm²; 95% confidence interval [CI] 0.03 to 0.08; I² = 67%; P < 0.001), while the BMD of the lumbar spine did not significantly change (P > 0.05). In the subgroup analysis, the BMD of the femoral neck decreased significantly at 12 months in obese patients who underwent metabolic surgery (MD = 0.08 g/cm²; 95% CI 0.04 to 0.13; I² = 84%; P < 0.001), while it did not significantly change in obese patients who underwent lifestyle treatment (P > 0.05).

CONCLUSION

Regardless of whether the patients underwent metabolic surgery or lifestyle treatment, the BMD of the total hip significantly decreased in obese patients after weight loss. Different methods used to lose weight may have different effects on the BMD of the femoral neck. Prospective studies, preferably randomized controlled trials (RCTs), are still required to investigate whether the effects of the two treatments on bone metabolism are truly different.

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.

Roux-en-Y gastric bypass and gastric sleeve surgery result in long term bone loss

OBJECTIVES

Little is known about the long-term skeletal impact of bariatric procedures, particularly the increasingly commonly performed gastric sleeve surgery (GS). We examined bone density (BMD) change following three types of bariatric surgery Roux-en-Y gastric bypass (RYGB), GS and laparoscopic adjustable gastric banding (LAGB), compared with diet, over 36 months.

METHODS

Non-randomized, prospective study of participants with severe obesity (n = 52), undergoing weight-loss interventions: RYGB (n = 7), GS (n = 21), LAGB (n = 11) and diet (n = 13). Measurements of calciotropic indices, gut hormones (fasting and post prandial) peptide YY (PYY), glucagon-like peptide 1 (GLP1) and adiponectin together with dual-X-ray absorptiometry and quantitative computed tomography scans were performed thorough the study.

RESULTS

All groups lost weight during the first 12 months. Despite weight stability from 12 to 36 months and supplementation of calcium and vitamin D, there was progressive bone loss at the total hip (TH) over 36 months in RYGB -14% (95% CI: -12, -17) and GS -9% (95% CI: -7, -10). In RYGB forearm BMD also declined over 36 months -9% (95% CI: -6, -12) and LS BMD declined over the first 12 months -7% (95% CI: -3, -12). RYGB and GS groups experienced significantly greater bone loss until 36 months than LAGB and diet groups, which experienced no significant BMD loss. These bone losses remained significant after adjustment for weight loss and age. RYGB and GS procedures resulted in elevated postprandial PYY, adiponectin and bone turnover markers up to 36 months without such changes among LAGB and diet participants.

CONCLUSIONS

RYGB and GS but not LAGB resulted in ongoing TH bone loss for three postoperative years. For RYGB, bone loss was also observed at LS and non-weight-bearing forearms. These BMD changes were independent of weight and age differences. We, therefore, recommend close monitoring of bone health following RYGB and GS surgeries.

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.

The rise of one anastomosis gastric bypass: insights from surgeons and dietitians

One anastomosis gastric bypass/Mini Gastric Bypass (OAGB/MGB) is an emerging bariatric surgery (BS) technique. We evaluated and compared attitudes of bariatric surgeons and dietitians towards the considerations for choosing BS-type ("Decision-making"), the contributing factors to the rise of OAGB/MGB in Israel ("OAGB/MGB-rise") and notions regarding the occurrence of gastrointestinal (GI) symptoms and nutritional deficiencies following OAGB/MGB. Anonymous online surveys were distributed. The participants were asked to rate by a 10-point Likert scale (0 = not at all; 100 = very much/often) their attitudes towards "Decision-making", "OAGB/MGB-rise" and occurrence of GI symptoms and nutritional deficiencies following OAGB/MGB. For "Decision-making" and "OAGB/MGB-rise", items were considered prioritized where ≥ 50% of the group considered them as 'very-important' (rating ≥ 80). Data on age, sex, years-in-practice and main workplace were also collected. A total of 106 professionals participated in the survey (42 surgeons; 64 dietitians). The respective mean age, years-in-practice and sex were 52.3 ± 8.7 vs. 42.3 ± 9.0 years, 21.0 ± 10.8 vs. 15.5 ± 9.2 years and 85.7% vs. 3.1% males. The inter-observer agreement for prioritized items related to "Decision-making" was fair (Kappa = 0.250; P = 0.257) and both groups prioritized patient's BMI, comorbidities and compliance. The inter-observer agreement for prioritized items related to "OAGB/MGB-rise" was moderate (Kappa = 0.550; P = 0.099) and both groups prioritized ease of performance, shorter operation duration and failure of former restrictive BS. Surgeons reported lower occurrence of nutritional deficiencies and GI symptoms as adverse effects of OAGB/MGB (P ≤ 0.033). The study highlights the views of bariatric surgeons and dietitians concerning factors that underpin the rise of OABG/MGB in Israel and possible rates of GI symptoms and nutritional deficiencies associated with this modality.

Bone Health Following Bariatric Surgery: An Update

Obesity rates are increasing rapidly, and bariatric surgery is currently the most effective tool for weight loss. Recently, bariatric surgery induced bone loss has gained attention. Such detrimental effect on bone is multifactorial and causes may include nutrient deficiencies, gut and gonadal hormonal changes, mechanical unloading, loss of lean mass, increased bone marrow fat, and increased risk of fall. This review describes the available evidence on bone loss and fracture risk following bariatric surgery and summarizes the guidelines on the topic. Increased bone resorption starts early postsurgery, and bone markers peak at 1-2 yr. Across studies, the drop in areal bone mineral density is inconsistent at the lumbar spine, while a 2%-5% drop at 6 mo and a 6%-10.5% at 9-12 mo are observed at the total hip. Conversely, studies using quantitative CT showed a 6%-7% decrease in volumetric bone mineral density at the lumbar spine at 6-12 mo postsurgery. These studies also report significant bone loss at the radius and tibia, in addition to alteration in bone microarchitecture. Fracture risk increases 2 yr after surgery, more so following malabsorptive procedures. Fractures were reported at axial, weight bearing sites and at appendicular sites. The available evidence is very heterogeneous, and mostly derived from studies on Roux-en-y gastric bypass in premenopausal women. Data on restrictive procedures is scarce. Our findings suggest that the early postoperative phase represents the "golden window" to intervene and promote bone health. More research is needed to determine the effect of different bariatric procedures on bone, to identify optimal interventions to prevent bone loss and to characterize high risk individuals who should be targeted.

Proceedings of the 2019 Santa Fe Bone Symposium: New Concepts in the Care of Osteoporosis and Rare Bone Diseases

The 20th annual Santa Fe Bone Symposium was held August 9-10, 2019, in Santa Fe, New Mexico, USA. This is an annual meeting devoted to clinical applications of recent advances in skeletal research that impact the care of patients with osteoporosis, metabolic bone diseases, and inherited bone diseases. Participants included practicing and academic physicians, fellows, advanced practice providers, fracture liaison service (FLS) coordinators, clinical researchers, and bone density technologists. The symposium consisted of lectures, case presentations, and panel discussions, with an emphasis on learning through interaction of all attendees. Topics included new approaches in the use of anabolic agents for the treatment osteoporosis, a review of important events in skeletal health over the past year, new and emerging treatments for rare bone diseases, the use of genetic testing for bone diseases in clinical practice, medication-associated causes of osteoporosis, new concepts in the use of estrogen therapy for osteoporosis, new Official Positions of the International Society for Clinical Densitometry, skeletal consequences of bariatric surgery, and update on the progress and potential of Bone Health TeleECHO, a virtual community of practice using videoconferencing technology to link healthcare professionals for advancing the care of osteoporosis worldwide. Sessions on rare bone diseases were developed in collaboration with the Rare Bone Disease Alliance. Symposium premeetings included an FLS workshop by the National Osteoporosis Foundation and others devoted to the use of new therapeutic agents for the care of osteoporosis and related disorders.

Obesity and hypovitaminosis D: causality or casualty?

Epidemiological studies reported that vitamin D deficiency represents an increasingly widespread phenomenon in various populations. Vitamin D deficiency is considered a clinical syndrome determined by low circulating levels of 25-hydroxyvitamin D (25(OH)D), which is the biologically-inactive intermediate and represents the predominant circulating form. Different mechanisms have been hypothesized to explain the association between hypovitaminosis D and obesity, including lower dietary intake of vitamin D, lesser skin exposure to sunlight, due to less outdoor physical activity, decreased intestinal absorption, impaired hydroxylation in adipose tissue and 25(OH)D accumulation in fat. However, several studies speculated that vitamin D deficiency itself could cause obesity or prevent weight loss. The fat-solubility of vitamin D leads to the hypothesis that a sequestration process occurs in body fat depots, resulting in a lower bioavailability in the obese state. After investigating the clinical aspects of vitamin D deficiency and the proposed mechanisms for low 25(OH)D in obesity, in this manuscript we discuss the possible role of vitamin D replacement treatment, with different formulations, to restore normal levels in individuals affected by obesity, and evaluate potential positive effects on obesity itself and its metabolic consequences. Food-based prevention strategies for enhancement of vitamin D status and, therefore, lowering skeletal and extra-skeletal diseases risk have been widely proposed in the past decades; however pharmacological supplementation, namely cholecalciferol and calcifediol, is required in the treatment of vitamin D insufficiency and its comorbidities. In individuals affected by obesity, high doses of vitamin D are required to normalize serum vitamin D levels, but the different liposolubility of different supplements should be taken into account. Although the results are inconsistent, some studies reported that vitamin D supplementation may have some beneficial effects in people with obesity.

Metabolic and Endocrine Consequences of Bariatric Surgery

Obesity is one of the most serious worldwide epidemics of the twenty-first century according to the World Health Organization. Frequently associated with a number of comorbidities, obesity threatens and compromises individual health and quality of life. Bariatric surgery (BS) has been demonstrated to be an effective treatment to achieve not only sustained weight loss but also significant metabolic improvement that goes beyond mere weight loss. The beneficial effects of BS on metabolic traits are so widely recognized that some authors have proposed BS as metabolic surgery that could be prescribed even for moderate obesity. However, most of the BS procedures imply malabsorption and/or gastric acid reduction which lead to nutrient deficiency and, consequently, further complications could be developed in the long term. In fact, BS not only affects metabolic homeostasis but also has pronounced effects on endocrine systems other than those exclusively involved in metabolic function. The somatotropic, corticotropic, and gonadal axes as well as bone health have also been shown to be affected by the various BS procedures. Accordingly, further consequences and complications of BS in the long term in systems other than metabolic system need to be addressed in large cohorts, taking into account each bariatric procedure before making generalized recommendations for BS. In this review, current data regarding these issues are summarized, paying special attention to the somatotropic, corticotropic, gonadal axes, and bone post-operative health.

Bone Health After Bariatric Surgery

Bariatric surgery results in long-term weight loss and improvement or resolution in obesity-related comorbidities. However, mounting evidence indicates that it adversely affects bone health. This review summarizes clinical research findings about the impact of bariatric surgery on skeletal outcomes. The literature is the largest and strongest for the Roux-en-Y gastric bypass (RYGB) procedure, as RYGB was the most commonly performed bariatric procedure worldwide until it was very recently overtaken by the sleeve gastrectomy (SG). Because SG is a newer procedure, its skeletal effects have not yet been well defined. Epidemiologic studies have now demonstrated an increased risk of fracture after RYGB and biliopancreatic diversion with duodenal switch, both of which include a malabsorptive component. As these epidemiologic data have emerged, patient-oriented studies have elucidated the bone tissue-level changes that may account for the heightened skeletal fragility. Bariatric surgery induces early and dramatic increases in biochemical markers of bone turnover. A notable feature of recent patient-oriented clinical studies is the application of advanced skeletal imaging modalities; studies address the limitations of dual-energy X-ray absorptiometry (DXA) by using quantitative computed tomography (QCT)-based modalities to examine volumetric bone mineral density and compartment-specific density and microstructure. RYGB results in pronounced declines in bone mass at the axial skeleton demonstrated by DXA and QCT, as well as at the appendicular skeleton demonstrated by high-resolution peripheral quantitative computed tomography (HR-pQCT). RYGB has detrimental effects on trabecular and cortical microarchitecture and estimated bone strength. Skeletal changes after RYGB appear early and continue even after weight loss plateaus and weight stabilizes. The skeletal effects of bariatric surgery are presumably multifactorial, and mechanisms may involve nutritional factors, mechanical unloading, hormonal factors, and changes in body composition and bone marrow fat. Clinical guidelines address bone health and may mitigate the negative skeletal effects of surgery, although more research is needed to direct and support such guidelines. © 2018 The Authors. JBMR Plus is published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.

Autologous Gluteal Augmentation with the Moustache Transposition Flap Technique

Massive weight loss patients and aesthetic patients can present with significant gluteal contour abnormalities. Gluteal ptosis, skeletal deformities, severe platypgia, and a paucity of donor fat for autologous transfer are common problems. Excisional procedures are used to treat massive-weight-loss contour abnormalities. These procedures present an opportunity to address severe gluteal deformities using autologous tissue augmentation. With a working knowledge of the relevant anatomy, sound surgical technique, and meticulous postoperative care, autologous gluteal autoaugmentation with circumferential body lift/excisional buttock lift using the "Moustache" flap technique will enhance massive weight loss body contouring outcomes and improve patient satisfaction.

Bone Health following Bariatric Surgery: Implications for Management Strategies to Attenuate Bone Loss

Bariatric surgery (BS) is an effective treatment for morbid obesity and its associated comorbidities. Following such a procedure, however, patients are at risk of developing metabolic bone disease owing to the combination of rapid weight loss, severely restricted dietary intake, and reduced intestinal nutrient absorption. Patients undergoing malabsorptive procedures are at a higher risk of postoperative bone health deterioration than those undergoing restrictive procedures; however, studies have demonstrated negative skeletal consequences of restrictive procedures as well. The clinical practice guidelines of some international associations have previously addressed preoperative evaluation and postoperative clinical care in order to maintain bone health in BS patients. Nevertheless, some issues regarding bone health in BS patients remain unclear owing to the lack of relevant randomized clinical trials, including doses of nutritional supplements pre- and post-BS. This review summarizes the current data regarding the skeletal consequences of BS and its mechanisms, with an emphasis on the preventive strategies and nutritional care that may be warranted in order to attenuate bone deterioration following BS.

The IGF-Axis and Diabetic Retinopathy Before and After Gastric Bypass Surgery

BACKGROUND

Laparoscopic gastric bypass (LGB) abruptly causes remission of type 2 diabetes (T2D). Such dramatic metabolic changes have previously been found to cause worsening of diabetic retinopathy (DR) and circulating insulin-like growth factor I (IGF-I) has been suggested as a causal mediator. We aimed to evaluate baseline imbalances in the circulating IGF-system and changes after LGB in patients with T2D.

METHODS

Prospective ocular examinations and measurement of the IGF-axis before and 3 and 12 months after LGB. IGF-bioactivity was measured by cell-based IGF-I receptor (IGF-IR) kinase activation assay (bioactive IGF). Total IGF-I, IGF-II and IGF binding protein (IGFBP) 1 and 3 were determined by immunoassays.

RESULTS

At baseline, 18 of 36 patients presented with DR. These patients had higher levels of bioactive IGF (p = 0.03) than patients without DR and this association was strengthened in multivariate analysis (p = 0.006). Three patients had worsening of DR, unrelated to other markers. In univariate analysis, bioactive IGF increased at 3 months (p = 0.05) but this change became insignificant in multivariate analysis (p = 0.11). IGFBP-1 increased whereas IGFBP-3 and total IGF-II decreased at the two postoperative visits (p ≤ 0.001). Total IGF-I showed no significant changes. HbA1c, glucose, HOMA-IR and lipids improved after surgery. Two patients did not complete the 12-month visit.

CONCLUSIONS

In obese T2D patients, bioactive IGF is a potential biomarker for DR and levels tended to increase 3 months after bariatric surgery. IGFBP-1 increased while IGFBP-3 and total IGF-II decreased postoperatively, but these changes were unassociated with the development of DR. Markers of the metabolic syndrome improved.

Relationship between Bone Health Biomarkers and Cardiovascular Risk in a General Adult Population

Purpose/Introduction: Osteoporosis (OP) and cardiovascular (CV) disease emerge as closely related conditions, showing common risk factors and/or pathophysiological mechanisms. The aim of this study was to evaluate the association between bone health markers (BHM) and individual CV risk factors and overall CV risk (FRAMINGHAM-FRS, and PROCAM scores) in a general adult population.

METHODS

In 103 subjects (21 males; age: 56 ± 12 years), vitamin D (25(OH)D), osteocalcin (OC), bone alkaline phospatase (BALP), procollagen I aminoterminal propeptide (P1NP), CTx-telopeptide, as well clinical history and life style were evaluated.

RESULTS

Aging (p < 0.001) and glycemia (p < 0.05) emerged as independent 25(OH)D predictors. Aging (p < 0.001), male sex (p < 0.05), and obesity (p < 0.05) represented independent OC determinants. Aging (p < 0.05) was the only independent BALP determinant. After multivariate adjustment, low 25(OH)D (<20 ng/mL) (Odds ratio OR (95% confidence intervals CI)) (5 (1.4-18) p < 0.05) and elevated OC (>75th percentile-16.6 ng/mL) (6.7 (1.9-23.8) p < 0.01) were found to be significant FRS predictors, while subjects with elevated OC and/or BALP (>75th percentile-9.8 μg/L) showed a higher CV risk as estimated by PROCAM (3.6 (1.2-10.7) p < 0.05). CTx and P1NP did not significantly correlate with CV risk factors or scores.

CONCLUSION

As we go further into bone and CV physiology, it is evident that a close relationship exists between these diseases. Further studies are needed to investigate mechanisms by which bone turnover markers are related to metabolic risk and could modulate CV risk. This knowledge may help to develop possible multiple-purpose strategies for both CV disease and OP prevention and treatment.

Bone turnover after bariatric surgery

OBJECTIVE

The aim of the present study was to evaluate parameters of bone and mineral metabolism after bariatric surgery.

SUBJECTS AND METHODS

This sectional study included data from medical records from 61 bariatric surgery (BS) patients (minimum period of 6 months after the procedure) and from 30 class II and III obese patients as a control group (Cont), consisting of daily dietary intake of macronutrients, calcium and sodium, serum 25(OH)D and parathyroid hormone (PTH) and other biochemical serum and urinary parameters. Bone alkaline phosphatase (BAP), leptin, fibroblast growth factor-23 (FGF-23) and deoxypyridinoline (DPYD) were determined from available banked serum and urinary samples.

RESULTS

Mean body mass index (BMI), median energy, carbohydrate, protein and sodium chloride consumption were significantly lower in the BS versus Cont, but calcium and lipids were not. No significant differences were found in ionized calcium, 25(OH)D, PTH and fibroblast growth factor 23 (FGF-23) between groups. Mean serum BAP was significantly higher for BS versus Cont and had a positive correlation with time after the surgical procedure. Mean serum leptin was significantly lower and median urinary DPYD higher in BS versus Cont.

CONCLUSION

The present study showed an increase in bone markers of both bone formation and resorption among bariatric patients up to more than 7 years after the surgical procedure, suggesting that an increased bone turnover persists even at a very long-term follow-up in such patients.

Effects of obesity treatments on bone mineral density, bone turnover and fracture risk in adults with overweight or obesity

BACKGROUND

New evidence suggests that obesity is deleterious for bone health, and obesity treatments could potentially exacerbate this.

MATERIALS AND METHODS

This narrative review, largely based on recent systematic reviews and meta-analyses, synthesizes the effects on bone of bariatric surgery, weight loss pharmaceuticals and dietary restriction.

RESULTS AND CONCLUSIONS

All three obesity treatments result in statistically significant reductions in hip bone mineral density (BMD) and increases in bone turnover relative to pre-treatment values, with the reductions in hip BMD being strongest for bariatric surgery, notably Roux-en Y gastric bypass (RYGB, 8%-11% of pre-surgical values) and weakest for dietary restriction (1%-1.5% of pre-treatment values). Weight loss pharmaceuticals (orlistat or the glucagon-like peptide-1 receptor agonist, liraglutide) induced no greater changes from pre-treatment values than control, despite greater weight loss. There is suggestive evidence that liraglutide may increase bone mineral content (BMC) - but not BMD - and reduce fracture risk, but more research is required to clarify this. All three obesity treatments have variable effects on spine BMD, probably due to greater measurement error at this site in obesity, suggesting that future research in this field could focus on hip rather than spine BMD. Various mechanisms have been proposed for BMD loss with obesity treatments, notably reduced nutritional intake/absorption and insufficient exercise, and these are potential avenues for protection against bone loss. However, a pressing outstanding question is whether this BMD reduction contributes to increased fracture risk, as has been observed after RYGB, and whether any such increase in fracture risk outweighs the risks of staying obese (unlikely).

The Effects of Bariatric Surgery on Bone Metabolism

Most metabolic effects following bariatric surgery are favorable. One area in which the consequences seem to be detrimental is on skeletal health. Mechanisms that have been cited include malabsorption of calcium and vitamin D, decrease in mechanical loading, and changes in gastrointestinal and fat-derived hormone levels. It is important that the impact of these procedures on bone metabolism is closely examined. The significance of the bone loss that occurs, and its possible effect on future fracture risk, should also be evaluated.

Practical Recommendations of the Obesity Management Task Force of the European Association for the Study of Obesity for the Post-Bariatric Surgery Medical Management

Bariatric surgery is today the most effective long-term therapy for the management of patients with severe obesity, and its use is recommended by the relevant guidelines of the management of obesity in adults. Bariatric surgery is in general safe and effective, but it can cause new clinical problems and is associated with specific diagnostic, preventive and therapeutic needs. For clinicians, the acquisition of special knowledge and skills is required in order to deliver appropriate and effective care to the post-bariatric patient. In the present recommendations, the basic notions needed to provide first-level adequate medical care to post-bariatric patients are summarised. Basic information about nutrition, management of co-morbidities, pregnancy, psychological issues as well as weight regain prevention and management is derived from current evidences and existing guidelines. A short list of clinical practical recommendations is included for each item. It remains clear that referral to a bariatric multidisciplinary centre, preferably the one performing the original procedure, should be considered in case of more complex clinical situations.

Vitamin D alteration associated with obesity and bariatric surgery

Obesity and severe obesity constitute growing serious health problems reaching epidemic proportion in most countries. Interactions and relationships between obesity and bone tissue and its metabolism are complex but are more and more studied and recognized. Obesity is associated with an altered hormonal profile including particularly bone-regulating hormones like vitamin D. Bariatric surgery procedures, thanks to their effectiveness to achieve therapeutic endpoints for comorbidities associated with obesity, have had an increasing success. However, these surgeries by producing mechanical restriction and or malabsorption syndrome lead to nutritional deficiencies including vitamin D. In this review, we aim to (1) discuss the nutritional deficiency of vitamin D in the obese, (2) to summarize the different surgical options in bariatric surgery and to present the evidence concerning these procedures and their associated profile in vitamin D post-operative insufficiency, (3) to present the different recommendations in clinical practice to prevent or treat vitamin D deficiencies or insufficiencies in patients treated by bariatric surgery and finally to introduce emerging assumptions on the relationship between vitamin D, microbiota composition and circulating bile acids. Impact statement Obesity and severe obesity constitute growing serious health problems reaching epidemic proportion in most countries with a prevalence increasing from 6.4 in 1975 to 14.9% in 2014. This present review summarizes currently available data on vitamin D deficiencies in the obese population before and after bariatric surgery. The important evidence emerging from our evaluation confirms that obese patients are at risk of multiple nutritional deficiencies, especially vitamin D deficiency, before bariatric surgery. Our survey confirms that the precise role of the gut microbiome and its associated changes on the vitamin D metabolism after the different bariatric surgery procedures has not yet been studied. Furthermore, whether differences in the microbiota may alter the therapeutic responses to vitamin D is not known.

Bariatric Surgery: What the Rheumatologist Needs to Know

A staggering 76 million adults are obese in the United States. It is known that obesity contributes to increased incidence and worse disease outcomes in many rheumatic conditions. Bariatric surgery has emerged as the most effective treatment modality for the morbidly obese, leading to substantial and sustained weight loss. The purpose of this review article is to summarize the findings of studies investigating the effect of substantial weight loss achieved through bariatric surgery on rheumatic disease and outcomes. Second, with an increasing number of patients undergoing bariatric surgery, it is important for the rheumatologist to have a basic understanding of the commonly performed bariatric procedures and to be aware of important nutritional deficiencies and medication restrictions that apply to this patient population.

Effects of Gastric Bypass and Gastric Banding on Bone Remodeling in Obese Patients With Type 2 Diabetes

CONTEXT

Roux-en-Y gastric bypass (RYGB) leads to high-turnover bone loss, but little is known about skeletal effects of laparoscopic adjustable gastric banding (LAGB) or mechanisms underlying bone loss after bariatric surgery.

OBJECTIVE

To evaluate effects of RYGB and LAGB on fasting and postprandial indices of bone remodeling.

DESIGN AND SETTING

Ancillary investigation of a prospective study at 2 academic institutions.

PARTICIPANTS

Obese adults aged 21-65 years with type 2 diabetes who underwent RYGB (n = 11) or LAGB (n = 8).

OUTCOMES

Serum C-terminal telopeptide (CTX), procollagen type 1 N-terminal propeptide (P1NP), and PTH were measured during a mixed meal tolerance test at baseline, 10 days and 1 year after surgery. Changes in 25-hydroxyvitamin D, polypeptide YY (PYY), glucagon-like peptide-1, glucose-dependent insulinotropic peptide, and insulin were also assessed.

RESULTS

Fasting CTX increased 10 days after RYGB but not LAGB (+69 ± 23% vs +12±12%, P < .001), despite comparable weight loss at that time. By 1 year, fasting CTX and P1NP increased more after RYGB than LAGB (CTX +221 ± 60% vs +15 ± 6%, P<0.001; P1NP +93 ± 25% vs -9 ± 10%, P < .001) and weight loss was greater with RYGB. Changes in CTX were independent of PTH and 25-hydroxyvitamin D but were associated with increases in fasting PYY. Postprandial suppression of CTX was more pronounced after RYGB than LAGB at 10 days and 1 year postoperatively.

CONCLUSIONS

RYGB is accompanied by early increases in fasting indices of bone remodeling, independent of weight loss or changes in PTH or 25-hydroxyvitamin D. LAGB did not affect bone markers. PYY and other enterohormonal signals may play a role in RYGB-specific skeletal changes.

Abnormal calcium, 25(OH)vitamin D, and parathyroid hormone after biliopancreatic diversion; correction through elongation of the common tract and reduction of the gastric pouch

BACKGROUND

Biliopancreatic diversion (BPD) is a surgical technique burdened, in some instances, by clinical evidence of malabsorption and intractable diarrhoea.

OBJECTIVES

To compare calcium metabolism together with weight in patients undergoing BPD versus BPD followed by revisional surgery because of side effects of BPD or ineffectiveness of BPD.

SETTING

University hospital.

METHODS

Twenty-seven patients underwent BPD. After a median period of 48 months, they underwent revisional surgery (elongation of the common limb from 50 to 200 cm and reduction of the gastric pouch from 500 to 40 mL) and were observed for a total period of 120 months; 40 patients only underwent BPD (controls) and were observed for an identical period.

RESULTS

At baseline, 24 patients (8 revisional surgery and 16 controls) had increased parathyroid hormone (PTH) levels, and only 3 patients had normal 25(OH)vitamin D levels; calcium declined, even within normal limits, and PTH increased in the revisional surgery group. After revisional surgery, patients experienced a further decrease of weight, together with a reduction of PTH levels, an increase of 25(OH)vitamin D levels, and an increase of calcium levels. Weight loss was inverserly associated with an increase of 25(OH)vitamin D and directly associated with change of PTH.

CONCLUSION

This study suggests that it is possible to control effects of BPD on calcium metabolism through a revisional procedure leading to lesser malabsorption and to greater restriction of the gastric pouch. It should be considered in the presence of significant side effects due to excessive malabsorption.

Bone mineral density and body composition after laparoscopic sleeve gastrectomy in men: A short-term longitudinal study

INTRODUCTION

Longitudinal changes in bone and body composition occurring in obese men after laparoscopic sleeve gastrectomy (LSG) has been evaluated.

METHODS

In short-term longitudinal study, 25 obese men in mean baseline age 44.8 ± 10.9 years and mean body mass index (BMI) 43.3 ± 4.4 kg/m(2)were assessed after undergoing LSG for obesity. Bone mineral density (BMD) (spine, femoral neck [FN], total hip [TH], and total body [TB]) and body composition (TB bone mineral content [BMC], fat, % of fat, lean, lean BMC, total mass) were assessed at baseline, and after three and six months.

RESULTS

Mean body measurements, including weight, BMI, waist and hips, decreased significantly over the study period (p < 0.0001). FN BMD (p < 0.01) and TH BMD (p < 0.001) decreased, and spine BMD increased significantly (p < 0.001). TB BMD did not change. Weight decreased by 21.3 ± 7.3%, BMI by 21.2 ± 7.3%, FN BMD by 3.32 ± 6.35%, TH BMD by 3.51 ± 3.95% whereas spine BMD increased by 2.89 ± 5.1%. TB BMC increased by 2.4 ± 4.62%; all other variables relating to body composition decreased: fat by 33.0 ± 9.6%, lean mass by 12.8 ± 6.1%, lean BMC by 12.3 ± 5.9%, total mass by 20.1 ± 6.4%, and % fat by 15.8 ± 7.2%.

CONCLUSIONS

After LSG, body size and variables related to body composition (except for TB BMC) decreased with an accompanying decrease in FN BMD in the men in this study. Spine BMD increased, and TB BMD did not change.

Changes in bone mineral density after sleeve gastrectomy or gastric bypass: relationships with variations in vitamin D, ghrelin, and adiponectin levels

BACKGROUND

A major long-term concern after gastric bypass (GBP) is the risk of osteoporosis; however, little is known about this complication in patients undergoing sleeve gastrectomy (SG).

OBJECTIVE

To evaluate changes in bone mineral density (BMD) after GBP and SG, and its relationship with changes in vitamin D, parathyroid hormone (PTH), ghrelin, and adiponectin.

METHODS

Twenty-three women undergoing GBP (BMI 42.0 ± 4.2 kg/m2; 37.3 ± 8.1 years) and 20 undergoing SG (BMI 37.3 ± 3.2 kg/m2; 34.2 ± 10.2 years) were studied before and 6 and 12 months after surgery. BMD was measured by dual-energy X-ray absorptiometry. Plasma PTH, 25-hydroxyvitamin D (25-OHD), ghrelin, and adiponectin concentrations were determined. Food as well as calcium and vitamin D supplement intake was recorded.

RESULTS

Excess weight loss (mean ± SE), adjusted by baseline excess weight, was 79.1±3.8% and 74.9 ± 4.1% 1 year after GBP and SG, respectively (p = 0.481). Significant reduction in BMD for total body (TB), lumbar spine (LS), and femoral neck (FN) was observed after GBP. In the SG group, reduction in BMD was significant only for TB. Adjusted by baseline BMD, the difference between change in BMD for GBP vs. SG was not significant for TB, LS, or FN. Percent reduction in ghrelin concentration was a main factor related to total BMD loss (GBP group) and LS BMD loss (GBP and SG groups).

CONCLUSIONS

One year after gastric bypass, bone mineral density was significantly affected, mainly at the femoral neck. Decreases in bone mineral density were more dramatic among patients who had greater baseline BMD and greater reduction in ghrelin concentrations.

The neuropeptide Y-ergic system: potential therapeutic target against bone loss with obesity treatments

Obesity is no longer considered to provide protection against osteoporosis. Moreover, treatments for obesity are now suspected of reducing bone mass. With the escalating incidence of obesity, combined with increases in the frequency, duration and intensity of interventions used to combat it, we face a potential increase in health burden due to osteoporotic fractures. The neuropeptide Y-ergic system offers a potential target for the prevention and anabolic treatment of bone loss in obesity, due to its dual role in the regulation of energy homeostasis and bone mass. Although the strongest stimulation of bone mass by this system appears to occur via indirect hypothalamic pathways involving Y2 receptors (one of the five types of receptors for neuropeptide Y), Y1 receptors on osteoblasts (bone-forming cells) induce direct effects to enhance bone mass. This latter pathway may offer a suitable target for anti-osteoporotic treatment while also minimizing the risk of adverse side effects.

Skeletal effects of bariatric surgery: examining bone loss, potential mechanisms and clinical relevance

Bariatric surgery is the most effective therapeutic approach to morbid obesity, resulting in substantial weight loss and improved cardiometabolic profiles; however, a growing body of evidence suggests that bariatric procedures increase both skeletal fragility and the risk of related future fracture secondary to excessive bone loss. Prospective evidence shows that areal bone mineral density (BMD) assessed by dual energy X-ray absorptiometry (DXA) declines by as much as 14% in the proximal femoral regions, including the femoral neck and total hip, 12 months postoperatively. Lumbar spine areal BMD outcomes show greater 12-month postoperative variability across surgical procedures (-8 to +6%) and contrast with no change in volumetric BMD outcomes measured by quantitative computed tomography. Diminished mechanical loading, micronutrient deficiency and malabsorption, along with neurohormonal alterations, offer plausible underlying mechanisms to explain these observed post-bariatric bone changes, but most remain largely unsubstantiated in this population. Importantly, DXA-based skeletal imaging may have limited utility in accurately detecting bone change in people undergoing bariatric surgery; partly because excessive tissue overlying bone increases the variability of areal BMD outcomes. Moreover, a paucity of fracture and osteoporosis incidence data raises questions about whether marked post-bariatric surgery bone loss is clinically relevant or a functional adaptation to skeletal unloading. Future studies that use technology which is able to accurately capture the site-specific volumetric BMD and bone architectural changes that underpin bone strength in people undergoing bariatric surgery, that consider mechanical load, and that better quantify long-term fracture and osteoporosis incidence are necessary to understand the actual skeletal effects of bariatric surgery.

The micronutrient intake profile of a multicentre cohort of Australian LAGB patients

BACKGROUND

Patients who have undergone bariatric surgery have increased risks of developing micronutrient deficiencies. Translational research investigating the actual micronutrient intake of bariatric patients is limited. We examined the micronutrient intake of a multicentre cohort of laparoscopic adjustable gastric banding patients 1 year post-surgery. These data were compared to micronutrient recommendations for the general population.

METHODS

Consecutive patients from three bariatric surgery facilities in Melbourne, Australia, were invited to participate 12 months post-operatively. A validated food frequency questionnaire was posted to 215 prospective participants.

RESULTS

Of the 52 participants, micronutrient intakes from food and fluids alone were below population recommendations for calcium, folate, magnesium, potassium, retinol equivalents, thiamin and vitamin E. Males did not meet the recommended intakes for zinc, and iron intakes in pre-menopausal women were insufficient. Intakes lower than recommended levels for these micronutrients suggest inadequate intake of foods from vegetable, dairy, lean meat (or alternatives) and wholegrains. Micronutrient intakes below recommended levels in this patient group can be further explained by their macronutrient intakes that suggested diets of poor nutrient density. Recommendations for supplementation in this group have wide variations, usually having been developed through the presence of clinical and biochemical deficiencies.

CONCLUSIONS

Nutritional supplementation should be more extensive in scope and dosage than is currently recommended by some professional guidelines. Further long-term studies are needed to explore both macro- and micronutrient intakes on the morbidity and mortality of this patient population.

Bone mineral density after bariatric surgery. A systematic review

PURPOSE

Bone regulation system may be affected after bariatric surgeries, but procedures impact differently to bone mineral density (BMD) and measures restraining bone loss are frequently neglected until clinical consequences become manifest. This is a systematic review aimed to elucidate whether BMD loss is comparable after different bariatric surgeries.

MATERIALS AND METHODS

A search of morbid obese adults, undergone to bariatric surgery, with BMD measured by dual-energy X-ray absorptiometry at baseline and after surgery studies was performed in several databases. Studies were assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and COCHRANE Risk of Bias tool. The random model was selected for meta-analysis; heterogeneity was analyzed with T(2), inconsistency (I(2) > 50%) and Chi(2) (p < 0.10). Level of evidence and strength of recommendations were summarized using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE System).

RESULTS

Twelve studies met the selection criteria. After one year, reduction in total BMD in patients with mixed surgical procedures was significant: -0.03 g/cm(2) (CI 95% 0.00 to -0.06, p < 0.05). BMD was reduced by -0.12 g/cm(2) (CI 95% -0.10 to -0.15, p < 0.001) in the hip, -0.07 g/cm(2) (CI 95% -0.03 to -0.11, p < 0.001) in the column, and -0.03 g/cm(2) (IC 95% -0.02 to -0.04, p < 0.001) in the forearm, but not in restrictive surgeries. Studies included showed high heterogeneity and low quality of evidence.

CONCLUSIONS

Patients undergone to mixed bariatric surgery had significant higher BMD deterioration as demonstrated in this review, suggesting that more attention for preventing fractures is required.

A case-matched study of the differences in bone mineral density 1 year after 3 different bariatric procedures

BACKGROUND

Studies have reported decreased bone mineral density (BMD) after laparoscopic sleeve gastrectomy (LSG) and laparoscopic Roux-en-Y gastric bypass (LRYGB). Laparoscopic adjustable gastric banded plication (LAGBP) is a novel procedure resulting in a dual restrictive mechanism of weight loss without altering gastrointestinal anatomy. The objectives of this study were to compare the BMD changes at 1 year after LAGBP, LSG, and LRYGB.

METHODS

The sample included 120 patients (40 patients [13 men/27 premenopausal women] each in LAGBP, LSG, and LRYGB groups). The mean preoperative age and body mass index were 30.0±6.5 years and 39.5±3.8 kg/m2, respectively. BMD was measured using dual energy X-ray absorptiometry at the lumbar anteroposterior spine and total hip preoperatively and 1 year postoperatively.

RESULTS

The mean percentage of excess weight loss was 61.9%±16.8%, 77.1%±12.3%, and 72.7%±17.4% at 1 year after LAGBP, LSG, and LRYGB, respectively. The mean BMD at the lumbar anteroposterior spine remained unchanged in the LSG and LRYGB groups, but significantly increased in the LAGBP group. The mean BMD at the total hip significantly decreased in all groups compared to the preoperative values. However, the mean BMD was significantly higher in the LRYGB than in the LAGBP group.

CONCLUSION

Bone loss at the hips was observed in all patients, including those with adequate micronutrient supplementation. LRYGB caused significantly greater bone loss than the other procedures.

Bone metabolism after bariatric surgery

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

Body composition analysis by air displacement plethysmography in normal weight to extremely obese adults

OBJECTIVE

To compare body composition parameters estimated by air displacement plethysmography (ADP) to dual X-ray absorptiometry (DXA) in body mass index (BMI) classifications that include extremely obese (BMI ≥ 40.0 kg/m(2) ), and to examine if differences between analyses were influenced by BMI.

METHODS

Fat-free mass (FFM, kg), fat mass (FM, kg), and body fat (BF, %) were analyzed with both technologies.

RESULTS

All outcome measures of ADP and DXA were highly correlated (r ≥ 0.95, P < 0.001 for FFM, FM, and BF), but Bland-Altman analyses revealed significant bias (P < 0.01 for all). ADP estimated greater FFM and lower FM and BF (P < 0.01 for all). BMI explained 27% of the variance in differences between FFM measurements (P < 0.001), and 37 and 33% of the variances in differences between FM and BF measurements, respectively (P < 0.001 for both). Within normal weight and overweight classifications, ADP estimated greater FFM and lower FM and BF (P < 0.001 for all), but the opposite occurred within the extremely obese classification; ADP estimated lower FFM and greater FM and BF (P < 0.05 for all).

CONCLUSIONS

Body composition analyses by the two technologies were strongly congruent, but systematically different and influenced by BMI. Caution should be taken when utilizing ADP to estimate body composition parameters over a wide range of BMI classifications that include extremely obese.

Bone loss after bariatric surgery: causes, consequences, and management

Bariatric surgery is an effective and increasingly common treatment for severe obesity and its many comorbidities. The side-effects of bariatric surgery can include detrimental effects on bone and mineral metabolism. Bone disease in patients who have had bariatric surgery is affected by preoperative abnormalities in bone and mineral metabolism related to severe obesity. Changes that arise after bariatric surgery are specific to procedure type: the most pronounced abnormalities in calciotropic hormones and bone loss are noted after procedures that result in the most malabsorption. The most consistent site for bone loss after all bariatric procedures is at the hip. There are limitations of dual-energy x-ray absorptiometry technology in this population, including artefact introduced by adipose tissue itself. Bone loss after bariatric surgery is probably multifactorial. Proposed mechanisms include skeletal unloading, abnormalities in calciotropic hormones, and changes in gut hormones. Few data for fracture risk in the bariatric population are available, and this is a crucial area for additional research. Treatment should be geared toward correction of nutritional deficiencies and study of bone mineral density in high-risk patients. We explore the skeletal response to bariatric surgery, potential mechanisms for changes, and strategies for management.

Bariatric surgery in an obese patient with Albright hereditary osteodystrophy: a case report

Introduction

We report for the first time the case of a patient with Albright hereditary osteodystrophy and pseudopseudohypoparathyroidism who underwent a Roux-en-Y gastric bypass.

Case presentation

A 26-year-old obese Caucasian woman with Albright hereditary osteodystrophy with pseudopseudohypoparathyroidism (heterozygous mutation (L272F) in GNAS1 exon 10 on molecular analysis) was treated with gastric bypass. She had the classical features of Albright hereditary osteodystrophy: short stature (138cm), obesity (body mass index 49.5kg/m2), bilateral shortening of the fourth and fifth metacarpals, short neck, round and wide face with bombed front and small eyes. Before the gastric bypass was performed, biochemical determination revealed a slightly low serum calcium level (2.09mmol/L; normal range 2.1 to 2.5mmol/l), and an elevated parathyroid hormone level (87ng/L; normal range 10 to 70ng/L) associated with low vitamin D level (19μg/L; normal range 30 to 50μg/L). Vitamin D supplementation was prescribed before surgery. After the Roux-en-Y gastric bypass, she achieved a progressive substantial weight loss, from 94kg (body mass index 49.5kg/m2) to 49kg (body mass index 25.9kg/m2) in one year. Her weight then stabilized at 50kg (body mass index 26kg/m2) during our three years of follow-up. Before the operation and every three months after it, she was screened for nutritional deficiencies, and serum markers of bone turnover and renal function were monitored. Considering the deficiencies in zinc, magnesium, calcium, vitamin D and vitamin B12, appropriate supplementation was prescribed. Before and two years after the Roux-en-Y gastric bypass, a dual-energy X-ray absorptiometry assessment of bone density was performed that showed no changes on her lumbar column (0.882g/cm² and both T-score and Z-score of −1.5 standard deviation). In addition, bone microarchitecture with a measurement of her trabecular bone score was found to be normal.

Conclusion

This is the first case of Roux-en-Y gastric bypass described in a patient with pseudopseudohypoparathyroidism showing that such a procedure seems to be safe in obese patients with Albright hereditary osteodystrophy and pseudopseudohypoparathyroidism if appropriately followed up. As obesity is a prominent feature of Albright hereditary osteodystrophy, such patients might seek bariatric surgery. After a Roux-en-Y gastric bypass, patients with Albright hereditary osteodystrophy associated with pseudopseudohypoparathyroidism need long-term follow-up on nutritional and metabolic issues.

Bariatric surgery, bone loss, obesity and possible mechanisms

Bariatric surgery remains the most effective treatment for severely obese patients. However, the potential long-term effects of bariatric surgical procedures on health, including bone health, are only partially understood. The goal of this review was to present data on the impact of bariatric surgery on bone metabolism and to analyse possible reasons for the loss of bone mass that frequently occurs after bariatric surgery. Such factors include nutritional deficiencies, rapid weight loss per se, effects of fat-derived adipokines and gut-derived appetite-regulatory hormones. However, the relative roles of these factors in skeletal regulation and the mechanisms by which they work are not yet fully defined. Our review was focussed on the complex relationship between body weight, fat mass and bone mass, as well as peripheral and central mediators potentially involved in the dual regulation of both energy and bone homeostasis. We also review the data on the inverse relationship between central obesity, bone marrow fat and osteoporosis. As the number of bariatric operations increases, it is imperative to recognize mechanisms responsible for bariatric surgery-induced bone loss, with careful monitoring of bone health including long-term fracture incidence in patients undergoing these procedures.

Bone metabolism in obesity and weight loss

Excess body weight due to obesity has traditionally been considered to have a positive effect on bone; however, more recent findings suggest that bone quality is compromised. Both obesity and caloric restriction increase fracture risk and are regulated by endocrine factors and cytokines that have direct and indirect effects on bone and calcium absorption. Weight reduction will decrease bone mass and mineral density, but this varies by the individual's age, gender, and adiposity. Dietary modifications, exercise, and medications have been shown to attenuate the bone loss associated with weight reduction. Future obesity and weight loss trials would benefit from assessment of key hormones, adipokine and gut peptides that regulate calcium absorption, and bone mineral density and quality by using sensitive techniques in high-risk populations.

Bone mineral changes in spine and proximal femur in individual obese women after laparoscopic sleeve gastrectomy: a short-term study

BACKGROUND

The aim of the study was to establish longitudinal bone changes in obese women after laparoscopic sleeve gastrectomy (LSG).

METHODS

Twenty-nine women at baseline mean age of 40.41 ± 9.26 years and with mean body mass index (BMI) of 43.07 ± 4.99 kg/m(2) were included in a 6-month study. Skeletal status at hip [femoral neck (FN) and total hip (TH)] and spine was assessed at baseline, as well as in 3 and 6 months after surgery. Body size was measured at baseline and follow-up (weight, height, BMI, and waist).

RESULTS

Baseline body weight was 117.5 ± 18.4 kg. The mean body weight and BMI decreased by 17.9 % during the first 3 months after surgery to obtain 28.4 % after 6 months. At 6 months, BMD decreased significantly for spine by 1.24 %, FN 6.99 %, and TH 5.18 %. The changes after 3 months in individual subjects showed that, in the majority of subjects, FN and TH BMD decreased significantly (in 52 % and 69 % of subjects, respectively), and in 24 % loss of BMD was found at the spine. After 6 months, the corresponding, significant decreases in individual subjects were found in 72 %, 86 %, and 38 % of woman, respectively. Those with a significant loss of FN BMD tended to lose more weight (30 ± 9.47 versus 23.25 ± 6.08 kg, p = 0.061) than others; women with a significant decrease of FN BMD lost more weight than those with no such decrease (30.43 ± 8.07 versus 15 ± 1.91 kg).

CONCLUSION

LSG proved efficient for body weight reduction, however, with a parallel decline in bone mineral density.

Risk of fracture after bariatric surgery in the United Kingdom: population based, retrospective cohort study

OBJECTIVES

To estimate fracture risk in patients receiving bariatric surgery versus matched controls.

DESIGN

Population based, retrospective cohort study.

SETTING

Use of records from the United Kingdom General Practice Research Database, now known as the Clinical Practice Research Datalink (from January 1987 to December 2010).

PARTICIPANTS

Patients with a body mass index of at least 30, with a record of bariatric surgery (n=2079), and matched controls without a record (n=10,442). Each bariatric surgery patient was matched to up to six controls by age, sex, practice, year, and body mass index. Patients were followed from the date of bariatric surgery for the occurrence of any fracture. We used time dependent Cox regression to calculate relative rates of fracture, adjusted for disease and previous drug treatment, and time-interaction terms to evaluate fracture timing patterns.

MAIN OUTCOME MEASURE

Relative rates of any, osteoporotic, and non-osteoporotic fractures.

RESULTS

Mean follow-up time was 2.2 years. Overall, there was no significantly increased risk of fracture in patients who underwent bariatric surgery, compared with controls (8.8 v 8.2 per 1000 person years; adjusted relative risk 0.89, 95% confidence interval 0.60 to 1.33). Bariatric surgery also did not affect risk of osteoporotic and non-osteoporotic fractures. However, we saw a trend towards an increased fracture risk after three to five years following surgery, as well as in patients who had a greater decrease in body mass index after surgery, but this was not significant.

CONCLUSION

Bariatric surgery does not have a significant effect on the risk of fracture. For the first few years after surgery, these results are reassuring for patients undergoing such operations, but do not exclude a more protracted adverse influence on skeletal health in the longer term.

Examining the link between bariatric surgery, bone loss, and osteoporosis: a review of bone density studies

As the popularity of bariatric surgery to treat morbid obesity has risen, so has a concern of increased skeletal fragility secondary to accelerated bone loss following bariatric procedures. We reviewed cross-sectional and prospective literature reporting bone density outcomes following bariatric surgical treatment for morbid obesity. Prospective research provides evidence of hip and lumbar spine areal bone mineral density (aBMD) reductions primarily in women despite calcium and vitamin D supplementation. Femoral neck aBMD declines of 9-11% and lumbar spine aBMD reductions up to 8% were observed at the first post-operative year following malabsorptive procedures. Mean T- and Z-scores up to 25 years following surgery remained within normal and healthy ranges. Of those studies reporting development of osteoporosis following gastric bypass, one woman became osteoporotic after 1 year. Despite observed bone loss in the hip region post-surgery, data do not conclusively support increased incidence of osteoporosis or increased fracture risk in post-bariatric patients. However, given the limitations of dual energy X-ray absorptiometry technology in this population and the relative lack of long-term prospective studies that include control populations, further research is needed to provide conclusive evidence regarding fracture outcomes in this population.

Increased PTH and 1.25(OH)(2)D levels associated with increased markers of bone turnover following bariatric surgery

The objective of this study was to characterize changes in metabolic bone parameters following bariatric surgery. Seventy-three obese adult patients who underwent either gastric banding (GB), Roux-en-Y gastric bypass (RYGB), or biliopancreatic diversion with duodenal switch (BPD/DS) were followed prospectively for 18 months postoperatively. Changes in the calcium-vitamin D axis (25-hydroxyvitamin D (25OHD), 1,25-dihydroxyvitamin D (1,25(OH)(2)D), calcium, parathyroid hormone (PTH)), markers of bone formation (osteocalcin, bone-specific alkaline phosphatase) and resorption (urinary N-telopeptide (NTx)), as well as bone mineral density (BMD) were assessed at 3-month intervals during this time period. Bariatric surgery resulted in significant and progressive weight loss over 18 months. With supplementation, 25OHD levels increased 65.3% (P < 0.0001) by 3 months, but leveled off and decreased <30 ng/ml by 18 months. PTH initially decreased 21.4% (P = 0.01) at 3 months, but later approached presurgery levels. 1,25(OH)(2)D increased significantly starting at month 12 (50.3% increase from baseline, P = 0.008), and was positively associated with PTH (r = 0.82, P = 0.0001). When stratified by surgery type, median PTH and 1,25(OH)(2)D levels were higher following combined restrictive and malabsorptive operations (RYGB and BPD/DS) compared to GB. Bone formation/resorption markers were increased by 3 months (P < 0.05) and remained elevated through 18 months. Radial BMD decreased 3.5% by month 18, but this change was not significant (P = 0.23). Our findings show that after transient improvement, preoperative vitamin D insufficiency and secondary hyperparathyroidism persisted following surgery despite supplementation. Postoperative secondary hyperparathyroidism was associated with increased 1,25(OH)(2)D levels and increased bone turnover markers.