Evaluation of bone mineral density loss in morbidly obese women after gastric bypass: 3-year follow-up. Obes Surg. 2011;21:465-472. [PMID: 21188546 DOI: 10.1007/s11695-010-0338-1]

Quantitative analysis and stochastic modeling of osteophyte formation and growth process on human vertebrae based on radiographs: a follow-up study

Osteophytes are frequently observed in elderly people and most commonly appear at the anterior edge of the cervical and lumbar vertebrae body. The anterior osteophytes keep developing and will lead to neck/back pain over time. In clinical practice, the accurate measurement of the anterior osteophyte length and the understanding of the temporal progression of anterior osteophyte growth are of vital importance to clinicians for effective treatment planning. This study proposes a new measuring method using the osteophyte ratio index to quantify anterior osteophyte length based on lateral radiographs. Moreover, we develop a continuous stochastic degradation model with time-related functions to characterize the anterior osteophyte formation and growth process on cervical and lumbar vertebrae over time. Follow-up data of anterior osteophytes up to 9 years are obtained for measurement and model validation. The agreement test indicates excellent reproducibility for our measuring method. The proposed model accurately fits the osteophyte growth paths. The model predicts the mean time to onset of pain and obtained survival function of the degenerative vertebrae. This research opens the door to future quantification and mathematical modeling of the anterior osteophyte growth on human cervical and lumbar vertebrae. The measured follow-up data is shared for future studies.

Determinant factors of bone health after long-term of Roux-en-Y gastric bypass surgery: A cross-sectional study

OBJECTIVES

The aim of this study was to evaluate bone health and the potential influencing factors of bone metabolism disorders in adults ≥5 y after Roux-en-Y gastric bypass (RYGB) surgery.

METHODS

In this cross-sectional study, patients who were ≥5 y post-RYGB were invited. Bone health considered as bone mineral content (BMC) and bone mineral density (BMD) in this study was assessed by dual x-ray absorptiometry. We also assessed 25-hydroxy-vitamin D concentrations, individual ultraviolet B radiation levels, serum ionized calcium, alkaline phosphatase, parathyroid, anthropometric, and body composition.

RESULTS

The study evaluated 104 adults (90% women; 49.6 ± 9.1 y old; postoperative period 8.7 ± 2.2 y). Lumbar and femoral BMC and BMD were positively correlated to body mass index (BMI), appendicular lean mass (ALM), and negatively to %excess of weight loss (EWL). Femoral BMD was negatively correlated to age, and both femoral BMD and BMC were positively correlated to weekly exposed body part score. Sex, age, BMI, ALM, and weekly exposed body part score explained 35% and 54% of the total variance of femoral BMD and BMC, respectively.

CONCLUSIONS

The present findings suggested that older age, lower BMI, higher %EWL, lower ALM, and lower weekly body part exposure score are important determinants in lowering BMD and BMC parameters in long-term post-bariatric surgery individuals, rather than serum 25-hydroxy-vitamin D and parathyroid.

Long-Term Changes in Bone Density and Bone Metabolism After Gastric Bypass Surgery: a Retrospective Cohort Study

PURPOSE

Patients with severe obesity submitted to Roux-en-Y gastric bypass (RYGB) are at risk of developing long-term hypovitaminosis D and secondary hyperparathyroidism (SHPT) as well as osteometabolic disease. This study aimed to evaluate calcium-vitamin D-PTH axis and bone mineral density (BMD) changes from post-RYGB patients who were followed-up until a median of 5 years.

MATERIALS AND METHODS

Vitamin D deficiency was defined as 25-hydroxyvitamin D <20 ng/mL and SHPT as PTH >68 pg/mL, in patients with normal serum creatinine and calcium. BMD was estimated by dual-energy X-ray absorptiometry (DXA, g/cm²).

RESULTS

We included 127 post-RYGB patients (51±10.6 years, 87.4% self-declared White, 91.3% female, 52.8% postmenopausal). Vitamin D deficiency prevalence was the highest (41.5%) in the second year and the lowest (21.2%) in the third year (p<0.05). SHPT prevalence was 65.4% in the second year and increased to 83.7% in the sixth year (p<0.05). Patients with low BMD in lumbar, femoral neck, and total proximal femur were older and presented menopausal status more frequently than normal BMD group (p<0.05). Older age was a risk marker for altered BMD in femoral neck (OR=1.185; 95% CI 1.118-1.256) and in total proximal femur (OR=1.158; 95% CI 1.066-1.258), both after adjusting for follow-up and excess weight loss.

CONCLUSION

After 5 years, most bariatric patients presented calcium-vitamin D-PTH axis disruption, in which SHPT was more frequent than hypovitaminosis D. Older patients and menopausal women presented higher rates of low BMD, and older age was a risk marker, especially for low BMD in femoral sites.

Evaluation of bone density and skeletal muscle mass after sleeve gastrectomy using computed tomography method

Introduction

Sleeve gastrectomy is the most common surgical procedure to reduce weight and treat metabolic complications in patients with moderate-to-severe obesity; however, it affects the musculoskeletal system. Dual-energy X-ray absorptiometry (DXA), which is commonly used to measure bone mineral density (BMD), may be affected by excess fat tissue around the bones, interrupting BMD measurement. Due to the strong correlation between DXA and the Hounsfield units (HU) obtained from computed tomography (CT) scans, BMD assessment using clinical abdominal CT scans has been useful. To date, there has been no report of detailed CT evaluation in patients with severe obesity after sleeve gastrectomy.

Objective

This study investigated the effect of sleeve gastrectomy in severely obese patients on bone and psoas muscle density, and cross-sectional area using retrospective clinical CT scans.

Methods

This was a retrospective observational study that included 86 patients (35 males and 51 females) who underwent sleeve gastrectomy between March 2012 and May 2019. Patients' clinical data (age at the time of surgery, sex, body weight, body mass index (BMI), comorbidities, and preoperative and postoperative blood test results, HU of the lumbar spine and psoas muscle and psoas muscle mass index (PMI)) were evaluated.

Results

The mean age at the time of surgery was 43 years, and the body weight and BMI significantly reduced (p < 0.01) after surgery. The mean hemoglobin A1c level showed significant improvement in males and females. Serum calcium and phosphorus levels remained unchanged before and after surgery. In CT analysis, HU of the lumbar spine and psoas muscle showed no significant decrease, but PMI showed a significant decrease (p < 0.01).

Conclusions

Sleeve gastrectomy could dramatically improve anthropometric measures without causing changes in serum calcium and phosphorus levels. Preoperative and postoperative abdominal CT revealed no significant difference in the bone and psoas muscle density, and the psoas muscle mass was significantly decreased after sleeve gastrectomy.

Changes in the Bone Mineral Density after Sleeve Gastrectomy vs. Roux-En-Y Gastric Bypass 2 Years after Surgery

The aim of this study was to compare the analytical and densitometric changes 2 years after Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG). A retrospective study of a prospectively collected database was performed. Morbidly obese patients undergoing RYGB or SG, as primary bariatric procedures, were included. Weight loss; analytical levels of parathormone (PTH), vitamin D, and calcium; and densitometric parameters were investigated. In total, 650 patients were included in the study, and 523 patients (80.5%) underwent RYGB and 127 (19.5%) SG. There were no significant differences in excess weight loss at 24 months between both groups. When comparing preoperative and postoperative values, a significantly greater increase in PTH values was observed in the RYGB group, whereas there were no significant differences in calcium and vitamin D levels. The mean t-score values decreased after surgery at all the locations and in both groups. The reduction in the t-score was significantly greater in the RYGB group at the femoral trochanter and lumbar spine. A decrease in bone mineral density (BMD) was observed after both techniques. The mean BMD decrease was significantly greater in the femoral trochanter and lumbar spine after RYGB.

Effects of Roux-en-Y Gastric Bypass Versus Sleeve Gastrectomy on Body Composition for Patients with a BMI > 35 kg/m2 at 1 Year After Surgery

PURPOSE

Effects of Roux-en-Y gastric bypass (RYGB) versus sleeve gastrectomy (SG) on body composition have not been well compared. This meta-analysis aimed to compare changes in fat mass (FM) and lean tissue mass (LTM) for patients with a BMI > 35 kg/m² at 1 year after RYGB and SG.

METHODS

PubMed, EMBASE, the Cochrane Library, and ClinicalTrials.gov were searched ending in December 2021 for eligible studies which reported baseline and postsurgical BMI, FM, and LTM.

RESULTS

Of 17 eligible studies, 831 patients were included, 484 following RYGB and 347 following SG. Weighted mean differences (WMD) and 95% confidence intervals (CI) were from a random-effects model. For patients with a BMI > 35 kg/m², RYGB resulted in a more substantial reduction of BMI (- 14.13 kg/m² [95%CI - 14.74, - 13.53] versus - 11.96 kg/m² [95%CI - 12.81, - 11.11], P < 0.001) and FM (- 26.22 kg [95%CI - 28.31, - 24.12] versus - 21.50 kg [95%CI - 25.52, - 17.48], P = 0.042) than SG, and a relatively weaker impact on LTM (- 8.28 kg [95%CI - 9.33, - 7.22] versus - 10.12 kg [95%CI - 11.55, - 8.68], P = 0.043).

CONCLUSION

This meta-analysis study indicates that RYGB is superior to SG in reducing excess FM for patients with a BMI > 35 kg/m² and seems to be more beneficial when LTM preservation is taken into consideration.

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.

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.

The magnitude and progress of lean body mass, fat-free mass, and skeletal muscle mass loss following bariatric surgery: A systematic review and meta-analysis

Postbariatric loss of muscle tissue could negatively affect long-term health due to its role in various bodily processes, such as metabolism and functional capacity. This meta-analysis aimed to unravel time-dependent changes in the magnitude and progress of lean body mass (LBM), fat-free mass (FFM), and skeletal muscle mass (SMM) loss following bariatric surgery. A systematic literature search was conducted in Pubmed, Embase, and Web of Science. Fifty-nine studies assessed LBM (n = 37), FFM (n = 20), or SMM (n = 3) preoperatively and ≥1 time points postsurgery. Random-effects meta-analyses were performed to determine pooled loss per outcome parameter and follow-up time point. At 12-month postsurgery, pooled LBM loss was -8.13 kg [95%CI -9.01; -7.26]. FFM loss and SMM loss were -8.23 kg [95%CI -10.74; -5.73] and -3.18 kg [95%CI -5.64; -0.71], respectively. About 55% of 12-month LBM loss occurred within 3-month postsurgery, followed by a more gradual decrease up to 12 months. Similar patterns were seen for FFM and SMM. In conclusion, >8 kg of LBM and FFM loss was observed within 1-year postsurgery. LBM, FFM, and SMM were predominantly lost within 3-month postsurgery, highlighting that interventions to mitigate such losses should be implemented perioperatively.

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.

Bone Mineral Density Trends During the First Year After Laparoscopic Sleeve Gastrectomy-a Cohort Study on 241 Patients

Purpose

Laparoscopic sleeve gastrectomy (LSG) is an effective weight loss procedure, but detrimental effects on bone health have been described. We aimed to assess the dynamics of regional and total bone mineral density (BMD) in a cohort of patients undergoing LSG and to capture gender differences in terms of evolution.

Materials and Methods

We conducted a retrospective study on 241 patients who underwent LSG to determine the regional and total BMD changes at 6 and 12 months after the intervention.

Results

One hundred ten males and 140 females (97 pre-, 43 postmenopausal) were included. Mean baseline body mass index (BMI) was 44.16 ± 6.11 kg/m² in males and 41.60 ± 5.54 kg/m² in females, reaching 28.62 ± 4.26 kg/m² and 27.39 ± 4.2 kg/m², respectively, at 12 months. BMD showed a continuous decline, with significant loss from 6 months postoperatively. There was a positive correlation between BMD and BMI decline at 12 months (r = 0.134, p < 0.05). Total BMD loss at 12 months was significantly greater in males than premenopausal females, independent of BMI variation and age. During the first 6 months, men lost significantly more bone mass than premenopausal and postmenopausal women (BMD variation was 2.62%, 0.27%, 1.58%, respectively). The second period (6–12 months) was similar in all three groups, revealing a further steady (~ 1.4%) BMD decline.

Conclusions

Our results are consistent with previous findings that LSG negatively impacts BMD, stressing the importance of bone health-oriented measures in postoperative care. Moreover, the impact that seems more significant in males warrants future exploration, as it might change clinical practice.

Graphical abstract

Long-Term Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density: a 4-Year Longitudinal Study

INTRODUCTION

Bone mineral density (BMD) declines in the initial years after bariatric surgery, but long-term skeletal effects are unclear and comparisons between sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) are rare.

DESIGN AND METHODS

An observational longitudinal study of obese patients undergoing SG or RYGB was performed. Whole-body (WB) BMD, along with BMD of the total hip (TH), femoral neck (FN), and lumbar spine (LS), was measured by dual-energy X-ray absorptiometry (DXA) before surgery and yearly thereafter for 4 years. Calciotropic hormones were also measured.

RESULTS

Forty-seven patients undergoing RYGB surgery and 28 patients undergoing SG were included. Four years after RYGB, BMD declined by 2.8 ± 5.8% in LS, 8.6 ± 5% in FN, 10.9 ± 6.3% in TH, and 4.2 ± 6.2% in WB, relative to baseline. For SG, BMD declined by 8.1 ± 5.5% in FN, 7.7 ± 6% in TH, 2.0 ± 7.2% in LS, and 2.5 ± 6.4% in WB after 4 years, relative to baseline. Vitamin D levels increased with supplementation in both groups. Whereas parathyroid hormone levels increased slightly in the RYGB group, they decreased modestly in the SG group (P < 0.05 in both groups).

CONCLUSIONS

Bone loss after 4 years was comparable between the two procedures, although RYGB was associated with a slightly greater decrease at the TH than SG. Bone health should therefore be monitored after both RYGB and SG.

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.

Three-year follow-up of bone status in male patients after bariatric surgery-a prospective single-center cohort study

BACKGROUND

In women, bariatric surgery (BS) leads to a decline in bone mineral density (BMD) and may ultimately lead to premature osteoporosis. The impact in men is largely unknown.

OBJECTIVE

To assess the effect of BS on bone metabolism in males.

SETTING

Single-center prospective cohort study.

METHODS

Twenty-four male BS candidates were prospectively enrolled. Anthropometric characteristics, serum gonadal hormones, markers of bone metabolism, and BMD were measured at baseline, 6-, 12- and 36-months postoperatively.

RESULTS

Roux-en-Y gastric bypass (RYGB) and adjustable gastric banding (AGB) were performed in 15 and 9 patients, respectively. Nineteen patients completed the 3-year follow-up. At 3 years, BMD of the right and left femur had decreased by 9.1 ± 7.2% and 9.4 ± 5.8% for RYGB and by 6.7 ± 3.9% and 4.5 ± 2.8% for AGB. Radius BMD had decreased by 14.0 ± 5.6% for RYGB and 5.9 ± 4.1% for AGB, i.e., significantly stronger for RYGB (P = .006). Serum parathyroid hormone increased in both groups and 13 of 19 patients developed Vitamin D deficiency. A significant increase of the bone resorption marker was seen only during the first year despite continuation of bone loss. Four patients developed de novo osteopenia or osteoporosis. No fractures were observed.

CONCLUSION

There are strong indications that male bone metabolism response after BS differs from female metabolism. The most affected site is the radius. In males, the cause of this BMD loss seems multifactorial, including mechanical unloading, hyperparathyroidism, and hypogonadism. However, clinical relevance remains unknown and therefore studies with longer-term follow-up are necessary.

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.

Bone mineral density changes after bariatric surgery

INTRODUCTION

Although bariatric surgery is associated with multiple health benefits, decreased bone mass is a known complication of the procedure. Roux-en-Y gastric bypass (RYGB) is associated with significant bone loss and increased fracture risk. However, data on the effect of sleeve gastrectomy (SG) on bone mineral changes are sparse. The impact of vitamin D and calcium levels on bone mineral density (BMD) after SG is also unknown.

METHODS

A retrospective chart review was performed to include patients who underwent RYGB or SG from 2014 to 2016 at a single institution. Patients were included if bone densitometry was performed preoperatively and within 2 years postoperatively. Serum 25-hydroxy vitamin D and calcium levels were collected preoperatively and at time of bone densitometry scan. BMD and T-score changes at the femoral neck, femoral trochanter, total hip, and lumbar spine were compared between RYGB and SG patients.

RESULTS

A total of 40 patients were included. 24 (60%) of patients underwent RYGB and 16 (40%) patients underwent SG. No statistically significant difference in baseline characteristics was noted between RYGB and SG patients. All measurements, except for serum 25-hydroxy vitamin D, were significantly decreased in RYGB patients, postoperatively. All measurements, except for BMD and T-score at the lumbar spine and serum 25-hydroxy vitamin D, were significantly decreased in SG patients, postoperatively. The extent of decrease in serum 25-hydroxyvitamin D was significantly associated with decreased BMD (p = 0.049) and T-score (p = 0.032) at the lumbar spine. The extent of decrease in serum calcium was significantly associated with decreased BMD (p = 0.046) at the femoral neck.

CONCLUSION

All patients were found to have decreased BMD after RYGB and SG. Surgery type was not a significant risk factor in BMD change. Despite vitamin D and calcium supplementation in all patients, a decrease in vitamin D and calcium levels were associated with a decrease in BMD. Close follow-up and treatment of vitamin D and calcium levels are warranted in all bariatric patients.

Bone Mineral Density, Parathyroid Hormone, and Vitamin D After Gastric Bypass Surgery: a 10-Year Longitudinal Follow-Up

Background

The aim of the present study was to study longitudinal changes in bone mineral density (BMD), vitamin D, and parathyroid hormone (PTH) levels in females over a 10-year period after laparoscopic Roux-en-Y gastric bypass (LRYGB).

Methods

Twenty-three women, mean age 43.4 ± 8.7 years and mean body mass index (BMI) 44.6 ± 5.17 kg/m² at baseline, were included. BMD, BMI, S-calcium, S-25(OH)-vitamin D, and fP-PTH were measured preoperatively and 2, 5, and 10 years postoperatively.

Results

Ten years after surgery, BMD of the spine and femoral neck decreased by 20% and 25%, respectively. Changes in serum levels of vitamin D, PTH, and calcium over the same period were small.

Conclusion

After LRYGB with subsequent massive weight loss, a large decrease in BMD of the spine and femoral neck was seen over a 10-year postoperative period. The fall in BMD largely occurred over the first 5 years after surgery.

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.

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.

Long-Term Effects in Bone Mineral Density after Different Bariatric Procedures in Patients with Type 2 Diabetes: Outcomes of a Randomized Clinical Trial

There is scant evidence of the long-term effects of bariatric surgery on bone mineral density (BMD). We compared BMD changes in patients with severe obesity and type 2 diabetes (T2D) 5 years after randomization to metabolic gastric bypass (mRYGB), sleeve gastrectomy (SG) and greater curvature plication (GCP). We studied the influence of first year gastrointestinal hormone changes on final bone outcomes. Forty-five patients, averaging 49.4 (7.8) years old and body mass index (BMI) 39.4 (1.9) kg/m², were included. BMD at lumbar spine (LS) was lower after mRYGB compared to SG and GCP: 0.89 [0.82;0.94] vs. 1.04 [0.91;1.16] vs. 0.99 [0.89;1.12], p = 0.020. A higher percentage of LS osteopenia was present after mRYGB 78.6% vs. 33.3% vs. 50.0%, respectively. BMD reduction was greater in T2D remitters vs. non-remitters. Weight at fifth year predicted BMD changes at the femoral neck (FN) (adjusted R²: 0.3218; p = 0.002), and type of surgery (mRYGB) and menopause predicted BMD changes at LS (adjusted R²: 0.2507; p < 0.015). In conclusion, mRYGB produces higher deleterious effects on bone at LS compared to SG and GCP in the long-term. Women in menopause undergoing mRYGB are at highest risk of bone deterioration. Gastrointestinal hormone changes after surgery do not play a major role in BMD outcomes.

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.

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.

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.

Targeting 1,25(OH)2D-mediated calcium absorption machinery in proximal colon with calcitriol glycosides and glucuronides

High intestinal calcium (Ca) absorption efficiency is associated with high peak bone mass in adolescents and reduced bone loss in adulthood. Transepithelial intestinal Ca absorption is mediated by 1,25-dihydroxyvitamin D (1,25(OH)₂D, calcitriol) through the vitamin D receptor (VDR). Most research on Ca absorption focuses on the proximal small intestine but evidence shows that large intestine plays a crucial role in whole body Ca homeostasis. We directly assessed and compared Ca absorption capacity at the proximal colon and duodenum using in situ ligated loops (2 mM Ca, 10 min). In C57BL/6 J mice, the proximal colon (26.2 ± 3.7 %) had comparable ability to absorb Ca as the duodenum (30.0 ± 6.7 %). In VDR knockout (KO) mice, Ca absorption efficiency was reduced by 67 % in duodenum and 48 % in proximal colon. These data suggest that large intestine could be targeted to improve Ca absorption and protect bone in at risk-groups (e.g. bariatric patients). Glycoside forms of calcitriol found in Solanum Glaucophyllum (Sg) leaf are biologically inert but can be activated in the colon upon bacterial cleavage of the glycosides. We conducted a study to test whether Sg leaf, as well as a novel, synthetic 1,3-diglucuronide form of calcitriol (1,3-diG) could target the proximal colon and upregulate genes involved in Ca absorption (i.e. Trpv6, S100g). 13-week-old female C57BL6/J mice were fed AIN93 G diet containing increasing levels of one of the two compounds for 2 weeks (delivering 0, 0.25, 0.5, 1, or 2 ng calcitriol equivalent per day). Both compounds induced a dose-dependent upregulation of Cyp24a1 and Trpv6 gene expression in the proximal colon. 1,3-diG also induced S100g gene expression in the proximal colon. Duodenal expression of Trpv6 was upregulated at higher doses of 1,3-diG but not Sg leaf. These data suggest that both glycosylated and glucuronidated calcitriol could be used to target the proximal colon but that dosing must be optimized to limit systemic effects that could cause hypercalcemia. Future studies will test the translational potential of these compounds to determine if they can increase Ca absorption at proximal colon and whether this can help protect bone.

Effects of Roux-en-Y Gastric Bypass on Osteoclast Activity and Bone Density in Morbidly Obese Patients with Type 2 Diabetes

INTRODUCTION

Roux-en-Y gastric bypass (RYGB) is a well-established treatment for morbid obesity and type 2 diabetes. The effects of RYGB on bone metabolism and bone health are largely unknown.

OBJECTIVE

Determine the changes in osteoclast function and bone density 1 year after RYGB as compared with a control group undergoing a diabetes support and education program (DSE).

DESIGN

A prospective cohort study with patients matched for weight and age assigned to RYGB or DSE.

SETTING

Large academic institution.

PATIENTS OR OTHER PARTICIPANTS

Patients with type 2 diabetes mellitus and morbid obesity (body mass index greater than 35 kg/m2).

INTERVENTION

Subjects either received laparoscopic RYBG or DSE, which consisted of nutritional, exercise, and dietary counseling performed by a certified diabetic educator and a nutritionist three times over a year.

MAIN OUTCOME MEASURE

Osteoclast activity, bone mineral density.

RESULTS

One year after, intervention subjects undergoing RYGB have a 280% increase in osteoclast activity as compared with a 7.6% increase in the DSE control group (P < 0.001). Furthermore, there was a statistically significant increase in sclerostin levels in subjects undergoing RYGB compared with an increase in the control group. The total bone mineral density was statistically unchanged within 1 year of intervention in both groups. A statistically significant decrease in bone mineral density in the left ribs (decrease of 6.8%, P < 0.05) and lumbar spine (decrease of 4.0%, P < 0.05) was seen 1 year after RYGB.

CONCLUSIONS

There is a significant increase in osteoclast activity observed 1 year after RYGB; the long-term clinical implications of this increased bone metabolism are unknown.

Changes in Bone Mineral Density Following Weight Loss Induced by One-Anastomosis Gastric Bypass in Patients with Vitamin D Supplementation

BACKGROUND

Little is known about changes in bone mineral density (BMD) following weight loss after one-anastomosis gastric bypass (OAGB) and the role of serum vitamin D and its supplementation on bone metabolism. We evaluated BMD after OAGB as a function of vitamin D supplementation with respect to a minimum threshold of 25-hydroxy-vitamin-D [25(OH)D] concentration, which could prevent or decelerate an eventual bone loss.

METHODS

Fifty bariatric patients who participated in the randomized controlled trial were included in this analysis. BMD and anthropometric measurements by DXA and laboratory parameters were assessed before (T0), at 6 (T6), and 12 months (T12) after surgery.

RESULTS

OAGB resulted in a 36% total body weight loss with a decrease in body fat and an increase in lean body mass. A significant decrease in BMD was seen in lumbar spine by 7%, left hip 13%, and total body 1%, but not in forearm. Bone turnover markers increased significantly but with normal parathyroid hormone concentrations. Weight loss was not associated with changes in BMD. A serum 25(OH)D concentration > 50 nmol/l at T6 and T12 (adequate-vitamin-D-group; AVD) showed a significant lower bone loss, compared to the inadequate-vitamin-D-group (IVD; < 50 nmol/l). Lower bone loss in the left hip showed a strong correlation with higher 25(OH)D concentrations (r = 0.635, p = 0.003).

CONCLUSION

These findings support a dose effect of vitamin D supplementation on bone health and suggest that 25(OH)D concentrations need to be above 50 nmol/l at least during the first postoperative year to decelerate bone loss in patients undergoing OAGB.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE

Clinicaltrials.gov (NCT02092376) at https://clinicaltrials.gov /. EudraCT (2013-003546-16) at https://eudract.ema.europa.eu /.

Obesity, Bariatric Surgery, and Fractures

CONTEXT

Obesity and its associated comorbidities are a recognized and growing public health problem. For a long time, obesity-associated effects on bone were considered to strengthen the bone, mainly because of the known relationship between body weight and bone mass and the long-term weight-bearing load effect on bone. However, recent epidemiologic studies have shown that obesity may not have a fully protective effect on the occurrence of fragility fractures. The goal of this article is to review updated information on the link between obesity, bariatric surgery, and fractures.

METHODS

The primary source literature for this review was acquired by searching a published database for reviews and articles up to January 2018. Additional references were selected through the in-depth analysis of the relevant studies.

RESULTS

We present data showing that overweight and obesity are often encountered in fracture cases. We also analyzed possible reasons and risk factors for fractures associated with overweight and patients with obesity. In addition, this review focuses on the complex effects of dramatic changes in body composition when interpreting dual-energy X-ray absorptiometry readings and findings. Finally, we review the data on the effects and consequences of bariatric surgery on bone metabolism and the risk of fractures in patients undergoing these procedures.

CONCLUSION

Because of various adiposity-induced effects, patients with obesity are at risk for fracture in certain sites. Bariatric surgery increases the risk of fractures in patients undergoing malabsorptive procedures.

Bilateral subtrochanteric femur insufficiency fractures after bariatric surgery: a case report

There have been case reports of proximal femur insufficiency fractures in patients who have previously undergone bariatric surgery. We present a follow-up case of a patient who developed bilateral complete proximal femur insufficiency fractures several years after bariatric surgery. Our patient underwent bilateral intramedullary fixation with a satisfactory postoperative outcome. We review and discuss the definition and pathogenesis of atypical femur fractures (AFFs), which may represent a larger category of insufficiency fractures not exclusive to bisphosphonate use, which includes patients with fractures after bariatric surgery.

VITAMIN D DEFICIENCY AND PARATOHOMMONIUM INCREASE IN LATE POSTOPERATIVE GASTRIC BYPASS IN ROUX-EN-Y

BACKGROUND

Roux-en-Y gastric bypass patients can experience changes in calcium metabolism and hyperparathyroidism secondary to vitamin D deficiency.

AIM

To evaluate nutritional deficiencies related to the calcium metabolism of patients undergoing gastric bypass with a 10-year follow-up.

METHOD

This is a longitudinal retrospective study of patients submitted to Roux-en-Y gastric bypass at a multidisciplinary clinic located in the Brazilian southeast region. The study investigated the results of the following biochemical tests: serum calcium, ionized calcium, vitamin D, and parathormone (PTH). The generalized estimating equations (GEE) determined the nutritional deficiencies using a significance level of 5%.

RESULTS

Among the patients who finished the study (120 months), 82.86% (n=29) had vitamin D deficiency, and 41.94% (n=13) had high PTH. Postoperative time had a significant effect on PTH (p=0.0059). The percentages of patients with vitamin D, serum calcium, and ionized calcium deficiencies did not change significantly over time.

CONCLUSION

One of the outcomes was vitamin D deficiency associated with secondary hyperparathyroidism. These findings reaffirm the importance of monitoring the bone metabolism of patients submitted to Roux-en-Y gastric bypass.

HEADINGS

Calcium deficiency. Vitamin D deficiency. Secondary hyperparathyroidism.

Fracture Risk After Gastric Bypass Surgery: A Retrospective Cohort Study

Gastric bypass surgery constitutes the most common and effective bariatric surgery to treat obesity. Gastric bypass leads to bone loss, but fracture risk following surgery has been insufficiently studied. Furthermore, the association between gastric bypass and fracture risk has not been studied in patients with diabetes, which is a risk factor for fracture and affected by surgery. In this retrospective cohort study using Swedish national databases, 38,971 obese patients undergoing gastric bypass were identified, 7758 with diabetes and 31,213 without. An equal amount of well-balanced controls were identified through multivariable 1:1 propensity score matching. The risk of fracture and fall injury was investigated using Cox proportional hazards and flexible parameter models. Fracture risk according to weight loss and degree of calcium and vitamin D supplementation 1-year postsurgery was investigated. During a median follow-up time of 3.1 (interquartile range [IQR], 1.7 to 4.6) years, gastric bypass was associated with increased risk of any fracture, in patients with and without diabetes using a multivariable Cox model (hazard ratio [HR] 1.26; 95% CI, 1.05 to 1.53; and HR 1.32; 95% CI, 1.18 to 1.47; respectively). Using flexible parameter models, the fracture risk appeared to increase with time. The risk of fall injury without fracture was also increased after gastric bypass. Larger weight loss or poor calcium and vitamin D supplementation after surgery were not associated with increased fracture risk. In conclusion, gastric bypass surgery is associated with an increased fracture risk, which appears to be increasing with time and not associated with degree of weight loss or calcium and vitamin D supplementation following surgery. An increased risk of fall injury was seen after surgery, which could contribute to the increased fracture risk. © 2018 American Society for Bone and Mineral Research.

Relevance of vitamin D deficiency in patients with chronic autoimmune atrophic gastritis: a prospective study

Background

Chronic autoimmune atrophic gastritis (CAAG) is an autoimmune disease characterized by hypo/achlorhydria. A role of CAAG in the pathogenesis of nutritional deficiencies has been reported, therefore we hypothesized a possible association between CAAG and 25-OH-Vitamin D [25(OH)D] deficiency. Aim of the present study is to evaluate the prevalence of 25(OH)D deficiency in CAAG patients. Methods: 87 CAAG patients (71 females; mean age 63.5 ± 12.8 years) followed at our Centre from January 2012 to July 2015 were consecutively evaluated. 25(OH)D, vitamin B₁₂, parathormone, and calcium were measured in all the CAAG patients. The results were compared with a control group of 1232 healthy subjects.

Results

In the CAAG group the mean 25(OH)D levels were significantly lower than in the control group (18.8 vs. 27.0 ng/ml, p < 0.0001). 25(OH)D levels < 20 ng/ml was observed in 57 patients, while levels < 12.5 ng/ml in 27 patients. A significant correlation between vitamin B₁₂ values at diagnosis and 25(OH)D levels was observed (r_s = 0.25, p = 0.01). Interestingly, the CAAG patients with moderate/severe gastric atrophy had lower 25(OH)D values as compared to those with mild atrophy (11.8 vs. 20 ng/ml; p = 0.0047). Moreover, the 25(OH)D levels were significantly lower in CAAG patients with gastric carcinoid as compared to those without gastric carcinoid (11.8 vs. 19.8 ng/ml; p = 0,0041).

Conclusion

Data from the present study showed a significant reduction of 25(OH)D levels in CAAG patients and a possible impairment of vitamin D absorption in CAAG may be postulated. Any implication to the genesis of gastric carcinoids remains to be elucidated.

Longitudinal 5-Year Evaluation of Bone Density and Microarchitecture After Roux-en-Y Gastric Bypass Surgery

CONTEXT

Bone health declines in the initial years after Roux-en-Y gastric bypass (RYGB), but long-term skeletal effects are unclear.

OBJECTIVE

To document longitudinal changes in bone mineral density (BMD) and microarchitecture 5 years after RYGB.

DESIGN, SETTING, AND PARTICIPANTS

Prospective 5-year observational study of 21 adults with severe obesity receiving RYGB at an academic medical center.

MAIN OUTCOME MEASURES

Spine and hip areal BMD were measured by dual-energy X-ray absorptiometry, and trabecular volumetric BMD (vBMD) of the spine was assessed by quantitative CT (QCT). We measured vBMD and microarchitecture of the distal radius and tibia by high-resolution peripheral QCT in a subset of subjects. Serum type I collagen C-terminal telopeptide (CTX) and procollagen type I N-terminal propeptide (P1NP) were also measured.

RESULTS

Areal BMD declined by -7.8% ± 7.6% at the spine and -15.3% ± 6.3% at the total hip by 5 years after RYGB (P ≤ 0.001), although the rate of bone loss slowed in later years. Trabecular spine vBMD decreased by -12.1% ± 12.3% by 5 years (P ≤ 0.001). At peripheral sites, vBMD continued to decrease steadily throughout 5 years, with parallel declines in cortical and trabecular microarchitecture, leading to decreases in estimated failure load of -20% and -13% at the radius and tibia, respectively (P < 0.001). Five years after RYGB, CTX and P1NP were 150% and 34% above baseline (P < 0.001 and P = 0.017, respectively).

CONCLUSIONS

Sustained high-turnover bone loss and bone microarchitectural deterioration occur in the 5 years after RYGB. Adults receiving RYGB warrant assessment of bone health.

Weight loss and bone mineral density in obese adults: a longitudinal analysis of the influence of very low energy diets

Background

The long-term effect of weight reduction on skeletal health is not well understood. The purpose of this study was to examine the impact of an intensive medical weight loss intervention using very low energy diet (VLED) (~ 800 cal/day) that result in significant changes in body weight, on total body bone mineral density (BMD) over 2 years.

Methods

We examined the impact of VLED-induced weight loss on BMD and FFM (Fat-free Mass) after 3–6 months and again while in weight maintenance at 2 years in 49 subjects. The effects of absolute and relative rate of weight reduction assessed by change in weight in kilograms were assessed using general linear modeling, with baseline BMD (or FFM) as a covariate, and age, sex and changes in body weight as primary model predictors.

Results

At the end of 2 years, the average weight loss was greater for men (weight: 23.51 ± 12.5 kg) than women (weight: 16.8 ± 19.2 kg) and BMD loss was greater among women (0.03 ± 0.04 g/cm² vs 0.01 ± 0.04 g/cm²) (all p < 0.05). After adjusting for baseline BMD, age, and sex, there was a small but significant association between total weight loss and 2-year BMD (β = − 0.001 g/cm²; p = 0.01). Similarly, there was a significant independent association between total weight loss and 2-year FFM (β = − 116.5 g; p < 0.01).

Conclusions

Despite significant weight loss with VLED, there was only a small loss is BMD.

Effects of Gastric Bypass Surgery on Bone Mass and Microarchitecture Occur Early and Particularly Impact Postmenopausal Women

Roux-en-Y gastric bypass (RYGB) surgery is a highly effective treatment for obesity but negatively affects the skeleton. Studies of skeletal effects have generally examined areal bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA), but DXA may be inaccurate in the setting of marked weight loss. Further, as a result of modestly sized samples of mostly premenopausal women and very few men, effects of RYGB by sex and menopausal status are unknown. We prospectively studied the effects of RYGB on skeletal health, including axial and appendicular volumetric BMD and appendicular bone microarchitecture and estimated strength. Obese adults (N = 48; 27 premenopausal and 11 postmenopausal women, 10 men) with mean ± SD body mass index (BMI) 44 ± 7 kg/m² were assessed before and 6 and 12 months after RYGB. Participants underwent spine and hip DXA, spine QCT, radius and tibia HR-pQCT, and laboratory evaluation. Mean 12-month weight loss was 37 kg (30% of preoperative weight). Overall median 12-month increase in serum collagen type I C-telopeptide (CTx) was 278% (p < 0.0001), with greater increases in postmenopausal than premenopausal women (p = 0.049). Femoral neck BMD by DXA decreased by mean 5.0% and 8.0% over 6 and 12 months (p < 0.0001). Spinal BMD by QCT decreased by mean 6.6% and 8.1% (p < 0.0001); declines were larger among postmenopausal than premenopausal women (11.6% versus 6.0% at 12 months, p = 0.02). Radial and tibial BMD and estimated strength by HR-pQCT declined. At the tibia, detrimental changes in trabecular microarchitecture were apparent at 6 and 12 months. Cortical porosity increased at the radius and tibia, with more dramatic 12-month increases among postmenopausal than premenopausal women or men at the tibia (51.4% versus 18.3% versus 3.0%, p < 0.01 between groups). In conclusion, detrimental effects of RYGB on axial and appendicular bone mass and microarchitecture are detectable as early as 6 months postoperatively. Postmenopausal women are at highest risk for skeletal consequences and may warrant targeted screening or interventions. © 2017 American Society for Bone and Mineral Research.

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.

Metabolic Effects of Bariatric Surgery

BACKGROUND

Obesity can be defined as a chronic subcortical brain disease, as there is an important neurophysiological component to its etiology based on changes in the functioning of those areas of the brain controlling food intake and reward. Extensive metabolic changes accompany bariatric surgery-based treatment of obesity. Consequently, the term “metabolic” surgery is being increasingly adopted in relation to the beneficial effects these procedures have on chronic diseases like type 2 diabetes.

CONTENT

In the present review, we focus on the key biochemical and physiological changes induced by metabolic surgery and highlight the beneficial effects accrued systemically with the use of an organ-based approach. Understanding the impact on and interactions between the gut, brain, adipose tissue, liver, muscle, pancreas, and kidney is key to understanding the sum of the metabolic effects of these operations.

SUMMARY

Further mechanistic studies are essential to assess the true potential of metabolic surgery to treat metabolic comorbidities of obesity beyond type 2 diabetes. Approaches that may mitigate the metabolic side effects of surgery also require attention. Understanding the positive impact of metabolic surgery on metabolic health may result in a wider acceptance of this intervention as treatment for metabolic, comorbid conditions.

Is Trabecular Bone Score Valuable in Bone Microstructure Assessment after Gastric Bypass in Women with Morbid Obesity?

Introduction: The effects of bariatric surgery on skeletal health raise many concerns. Trabecular bone score (TBS) is obtained through the analysis of lumbar spine dual X-ray absorptiometry (DXA) images and allows an indirect assessment of skeletal microarchitecture (MA). The aim of our study was to evaluate the changes in bone mineral density (BMD) and alterations in bone microarchitecture assessed by TBS in morbidly obese women undergoing Roux-en-Y gastric bypass (RYGB), over a three-year follow-up. Material/Methods: A prospective study of 38 morbidly obese white women, aged 46.3 ± 8.2 years, undergoing RYGB was conducted. Biochemical analyses and DXA scans with TBS evaluation were performed before and at one year and three years after surgery. Results: Patients showed normal calcium and phosphorus plasma concentrations throughout the study. However, 25-hydroxyvitamin D (25(OH)D₃) decreased, and 71% of patients had a vitamin D deficiency at three years. BMD at femoral neck and lumbar spine (LSBMD) significantly decreased 13.53 ± 5.42% and 6.03 ± 6.79%, respectively, during the three-year follow-up; however Z-score values remained above those for women of the same age. TBS was within normal ranges at one and three years (1.431 ± 106 and 1.413 ± 85, respectively), and at the end of the study, 73.7% of patients had normal bone MA. TBS at three years correlated inversely with age (r = −0.41, p = 0.010), body fat (r = −0.465, p = 0.004) and greater body fat deposited in trunk (r = −0.48, p = 0.004), and positively with LSBMD (r = 0.433, p = 0.007), fat mass loss (r = 0.438, p = 0.007) and lean mass loss (r = 0.432, p = 0.008). In the regression analysis, TBS remained associated with body fat (β = −0.625, p = 0.031; R² = 0.47). The fracture risk, calculated by FRAX^® (University of Sheffield, Sheffield, UK), with and without adjustment by TBS, was low. Conclusion: Women undergoing RYGB in the mid-term have a preserved bone MA, assessed by TBS.

The Effect of a Muscle Weight-Bearing and Aerobic Exercise Program on the Body Composition, Muscular Strength, Biochemical Markers, and Bone Mass of Obese Patients Who Have Undergone Gastric Bypass Surgery

BACKGROUND

The effect of an exercise program on the body composition, muscular strength (MS), biochemical markers, and bone mineral density (BMD) of individuals undergoing gastric bypass is unclear. We assessed lean mass (LM), MS, bone remodeling markers, and BMD before and after supervised weight-bearing and aerobic exercise training in obese patients who underwent Roux-en-Y gastric bypass (RYGB).

METHODS

This study included 37 obese patients (81.1% women, mean age 38.2 years, mean body mass index 42.4 ± 0.5 kg/m²). Whole body densitometry was used to evaluate pre- and postoperative BMD, total body fat, and LM. Serum calcium, parathyroid hormone, 25-hydroxyvitamin D, and bone remodeling markers were measured. MS was determined through the concentric 10 repetition maximum test. Postoperatively, participants were divided into two groups: the training group, who followed an exercise program (TG, n = 18), and the control group, who did not (CG, n = 19).

RESULTS

After 1 year, the TG showed a lower decrease in total BMD and at the lumbar spine and right hip compared with the CG (p < 0.001). The TG had lower mass reduction and an increase in upper limb LM compared with the CG (both p < 0.05). There was no significant difference between groups in bone markers or calcium metabolism. MS was higher in the TG than the CG (p < 0.05).

CONCLUSION

The supervised exercise program attenuated lumbar spine and right hip BMD loss and improved LM in the arms and overall MS but did not affect bone remodeling.

LONG-TERM BONE HEALTH AFTER ROUX-EN-Y GASTRIC BYPASS: A PILOT STUDY

OBJECTIVE

This cross-sectional study was undertaken to assess metabolic bone disease by examining bone mineral density (BMD), fracture prevalence, and nutritional factors pertinent to bone in a cohort >9 years post-Rouxen-Y gastric bypass (RYGB).

METHODS

Fifty-one subjects 9.4 to 36.0 years (mean 17.0 ± 8.1) post-RYGB provided a focused history. Dietary calcium and protein were assessed. Dual-energy X-ray absorptiometry (DXA) BMD at the spine, hip, and radius and routine serum chemistries, magnesium, phosphorus, parathyroid hormone, vitamin D, vitamin K, and micronutrients were analyzed. Sixteen subjects provided 24-hour urine for measurement of calcium.

RESULTS

The mean maximum weight loss was 70.3 ± 20 kg (47.4 ± 8.9%), and mean net weight loss was 46.9 ± 23.1 kg (31.2 ± 12.5%). The prevalence rates of fracture, secondary hyperparathyroidism, and vitamin D deficiency were 15.7%, 37%, and 39%, respectively. BMD was in the osteoporotic range in 27.5%. The mean calcium:creatinine clearance ratio was 0.0124 ± 0.0131. Median intakes of dietary calcium, total calcium, protein, and vitamin D were 582.5 mg, 947.5 mg, 50.2 g, and 1,000 IU, respectively. Mean Z-scores at all sites were <0 (P<.01). A negative correlation (P<.05) was noted between distal radius Z-score and net change in BMI. Net change in BMI was greater for those with osteoporosis than those without. (P<.05) Conclusion: Many years after RYGB, BMD remains lower than expected compared to an age-, sex-, race-, and weight-matched reference population and is correlated with the amount of weight lost. Deficiencies of Vitamin D and calcium are prevalent.

ABBREVIATIONS

BMD = bone mineral density BMI = body mass index Ca:Cr = calcium:creatinine DXA = dual-energy X-ray absorptiometry PTH = parathyroid hormone RYGB = Roux-en-Y gastric bypass UD = ultradistal WHO = World Health Organization.

The effect of bariatric surgery on serum 25-OH vitamin D levels: a systematic review and meta-analysis

Background

Concerns have emerged about post‐operative decreases in calcium and vitamin D following bariatric surgery. This review explores changes in metabolic bone health in persons with obesity undergoing gastric bypass surgery compared to non‐surgical controls, providing an updated and comprehensive perspective on the literature.

Methods

An electronic search was conducted in MEDLINE, Pubmed, EMBASE and Cochrane databases to 8 November 2016. Eligible trials included randomized controlled trials or controlled observational studies of patients who have undergone laparoscopic gastric bypass surgery. Statistical analysis was carried out using the Cochrane Collaboration Review Manager (RevMan 5.0), and a random effects model was implemented. Outcomes were expressed as weighted mean difference (WMD). The primary outcome examined was change in 25‐OH‐D levels at 12 months post surgery, and secondary outcomes included change in bone mineral density (BMD) measurements at 12 months post surgery at the lumbar spine (LS) and total hip (TH).

Results

At 12 months, there was no significant difference in 25‐OH vitamin D in the surgical group compared to controls (WMD = 6.79%; 95% CI: −9.01, 22.59; p = 0.40; I² = 68%). There was no statistically significant difference between fracture risk in the surgical population compared to controls (RR = 1.24; 95% CI: 0.99, 1.56; p = 0.06; I² = 0%). A significant BMD reduction was however shown at the TH (WMD, −7.33%, 95% CI = −8.70 to −5.97, p < .001, I² = 0%), and a trend towards decline was observed at the LS (WMD, −1.73%, 95% CI = −3.56 to 0.11, p = 0.06, I² = 0%). Changes at 24 months for applicable outcomes were similar to the results at 12 months.

Conclusions

Bariatric surgery may compromise metabolic bone health, but the paucity of high‐quality literature limits conclusions.