Short- and mid-term changes in bone mineral density after laparoscopic sleeve gastrectomy

A Systematic Review and Meta-Analysis of Vitamin D Status of Patients with Severe Obesity in Various Regions Worldwide

INTRODUCTION

Managing nutritional deficiencies is an essential component in the treatment of severe obesity. Vitamin D deficiency is often reported in investigations in severely obese cohorts. However, no prior study has summarized findings on this topic. Consequently, the aim of this systematic review and meta-analysis was to investigate the 25-hydroxyvitamin D [25(OH)D] status in individuals with severe obesity in different regions worldwide. We also evaluated levels of calcium, parathyroid hormone (PTH), and magnesium as secondary outcome measures.

METHODS

We searched Medline, PubMed, Scopus, the Cochrane Library, and EMBASE for relevant observational studies published in English from 2009 to October 2021. The heterogeneity index among the studies was determined using the Cochran (Q) and I2 tests. Based on the heterogeneity results, the random-effect model was applied to estimate the prevalence of vitamin D deficiency.

RESULTS

We identified 109 eligible observational studies. Overall, 59.44% of patients had vitamin D deficiency [25(OH)D <20 ng/mL], whereas 26.95% had vitamin D insufficiency [25(OH)D 20-30 ng/mL]. Moreover, the mean 25(OH)D level was 18.65 ng/mL in 96 studies. The pooled mean estimate of the serum calcium, PTH, and magnesium was 9.26 mg/dL (95% confidence interval [CI]: 9.19-9.32, I2 = 99.7%, p < 0.001), 59.24 pg/mL (95% CI: 54.98, 63.51, I2 = 99.7%, p < 0.001), and 0.91 mg/dL (95% CI: 0.84, 0.98, I2 = 100.0%, p < 0.001), respectively. The results of the subgroup analysis indicated that the mean estimates of 25(OH)D were highest in North America (21.71 ng/mL [19.69, 23.74], [I2 = 97.2%, p < 0.001]) and lowest in Southeast Asia (14.93 ng/mL [14.54, 15.33], [I2 = 0.0%, p = 0.778]).

CONCLUSION

The results obtained showed a significant prevalence of vitamin D deficiency among severely obese individuals in various geographical regions, whereas the highest and lowest mean estimates were reported for North America and Southeast Asia, respectively.

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

CONTEXT

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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.

Changes in Nutritional Outcomes After Sleeve Gastrectomy: a Systematic Review and Meta-analysis

PURPOSE

The aim of this meta-analysis is to evaluate the changes in nutritional indicators in individuals with obesity before and after SG.

MATERIALS AND METHODS

A systematic retrieval of the available literature was performed using PubMed, Embase, Web of Science, and Chinese National Knowledge Infrastructure databases. The following indicators were evaluated: serum 25-hydroxyvitamin D [25(OH)D], calcium, phosphorus, iron, vitamin B12, folate, magnesium, and zinc from pre-operation to post-operation.

RESULTS

A total of 38 studies met inclusion criteria. A significant increase was observed in serum 25(OH)D (SMD = 0.70, 95%CI 0.38 to 1.02, P < 0.001), phosphorus (SMD = 0.40, 95%CI 0.14 to 0.67, P = 0.003), iron (SMD = 0.50, 95%CI 0.38 to 0.62, P < 0.001), and folate (SMD = 0.37, 95%CI 0.09 to 0.65, P = 0.01) after SG. Nevertheless, the increasing trend of serum phosphorus (P = 0.143) and folate (P = 0.774) disappeared in the unprescribed subgroup. A significant decrease in serum zinc (SMD =  - 0.41, 95%CI - 0.81 to - 0.01, P = 0.044) was found after SG. No significant changes in serum calcium (SMD = 0.08, 95%CI - 0.09 to 0.25, P = 0.372), vitamin B12 (SMD = 0.10, 95%CI - 0.13 to 0.33, P = 0.398), and magnesium (SMD = 0.24, 95%CI - 0.10 to 0.58, P = 0.169) were observed. However, a significant decrease in serum calcium (P = 0.042) and vitamin B12 (P = 0.037) was found in the unprescribed subgroup.

CONCLUSIONS

Serum 25(OH)D, phosphorus, iron, and folate levels improved after a careful monitoring and due to a rigorous supplementation. The optimal dose of calcium, magnesium, and zinc supplementation has yet to be established; therefore, a broader supplementation of trace elements and minerals has to be suggested.

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.

Changes in bone mineral density following laparoscopic sleeve gastrectomy: 2-year outcomes

BACKGROUND

Emerging evidence suggests that sleeve gastrectomy (SG) leads to significant bone mineral density (BMD) losses, but there is a paucity of studies evaluating skeletal consequences beyond 12-months post-operatively.

OBJECTIVES

To evaluate BMD changes 2 years postoperatively.

SETTING

A university hospital.

METHODS

Thirty-three women (mean age: 34.4 ± 12.3 years) who underwent SG and completed 24 months of follow-up were evaluated prospectively at baseline and at 3 (M3), 6 (M6), 12 (M12), and 24 (M24) months postoperatively. Data collected included BMD at the total hip, femoral neck, and lumbar spine measured by dual-energy x-ray absorptiometry and anthropometrics, biochemical, nutritional, and physical activity parameters.

RESULTS

At M24, patients achieved a mean body mass index and excess weight loss of 32.4 ± 5.1 kg/m² and 64.5 ± 21.4%, respectively; however, weight stabilized at M12. Femoral neck BMD decreased significantly from baseline to M24 (.924 ± .124 versus .870 ± .129 g/cm², P < .001), with no change between M12 and M24 (P = .273). Total hip BMD decreased significantly from baseline to M24 (1.004 ± .105 versus .965 ± .132 g/cm², P < .001) but increased between M12 and M24 (P = .001). No significant changes were noted in lumbar spine BMD. The percentage of changes in the femoral neck and the total hip BMD from baseline to M24 positively correlated with postoperative excess weight loss (r = .352, P = .045, and r = .416, P = .018, respectively).

CONCLUSION

Despite notable weight loss, women who underwent SG experienced significant bone loss at the total hip and femoral neck more than 2 years postoperatively. Future studies should investigate intervention strategies to attenuate skeletal deterioration after SG.

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

Micronutrient status in bariatric surgery patients receiving postoperative supplementation per guidelines: Insights from a systematic review and meta-analysis of longitudinal studies

The micronutrient status and optimal monitoring schedule after bariatric surgery have not been sufficiently assessed. This systematic review and meta-analysis investigated the longitudinal changes in micronutrient status after bariatric surgery. PubMed, EMBASE, and Cochrane Library were searched for articles that measured preoperative and postoperative serum micronutrient levels in patients undergoing Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Among guideline-adherent studies, the longitudinal changes in micronutrient status were investigated using weighted mean difference (WMD) using a random-effects model. Among the 82 included studies, the guideline adherence rates for micronutrient supplementation after bariatric surgery did not exceed 20%. In patients supplemented per guidelines, vitamin A significantly decreased after RYGB by -7.54 (95% confidence interval [CI], -10.16 to -4.92) μg/dl at 12-23 months, vitamin E decreased after RYGB by -2.35 (95% CI, -3.65 to -1.05) μg/dl at ≥24 months, and ferritin by -54.93 (95% CI, -77.19 to -32.67] μg/L at ≥24 months after SG, compared with baseline, with moderate level of evidence. Significant decreases in micronutrient levels at certain follow-up intervals in studies with supplementation per guidelines need to be considered to establish a post-bariatric micronutrient monitoring schedule for timely detection and management of micronutrient deficiencies.

Assessment of nutritional status, body composition and blood biochemical parameters of patients following sleeve gastrectomy: 6 months follow up

BACKGROUND AND AIMS

Today, Sleeve gastrectomy (SG) has recently become the most common bariatric procedure among various bariatric surgical procedures due to its advantages. The aim of this study is to investigate nutritional status, body composition and biochemical parameters following SG.

METHODS

This was a prospective study, the subjects were patients who underwent SG at a special obesity clinic in İstanbul, Turkey, between 01.05.2017 and 01.11.2017. The mean body mass index (BMI) of the participants was 42.15 ± 4.84 kg/m² for men and 41.44 ± 4.34 kg/m² for women, preoperatively. Nutritional status, some anthropometric measurements and blood sampling were taken at each visit. Data were collected and analyzed for the present study at the following periods: pre-operation (pre-op), 1 month, 3 months and 6 months after surgery.

RESULTS

A total of 47 SG patients (20 men, 27 women) were evaluated. The mean BMI was 30.23 ± 3.56 kg/m² for men and 30.35 ± 4.36 kg/m² for women after 6 months and the amount of excess weight loss (EWL) increased in the 3 months (p < .001). Mean energy, fiber, vitamin A, vitamin C, vitamin B₁, niacin, vitamin B₁₂, folate, calcium, magnesium, iron, zinc, phosphorus and iodine were above the Dietary Reference Intake (DRI) recommendations. A significant association was found between protein intake and fat free mass loss in both genders after SG at 6 months (p < .05).

CONCLUSION

Nutrition deficiencies are common for patients after SG. Therefore, it is important to routinely monitor these patients with a professional team.

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.

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.

Modulation of the Gut Microbiota and Serum Biomarkers After Laparoscopic Sleeve Gastrectomy: a 1-Year Follow-Up Study

PURPOSE

Bariatric surgery is a treatment option for those affected by severe obesity. This study investigated changes in gut microbiota and serum biomarkers after laparoscopic sleeve gastrectomy (LSG).

MATERIALS AND METHODS

A total of 126 patients with morbid obesity who underwent LSG were enrolled in this study. Routine biochemical tests, hormonal (insulin and glucagon), and cytokine levels (IL-6, IL-1β, TNF-α, IL-10, and TGF-β 1) were measured, in addition, real-time PCR (quantitative PCR, qPCR) quantitated gut microbiota. All the parameters were measured pre-operatively, 3, and 12 months post-surgery (F0, F3, and F12, respectively).

RESULTS

At F3, the level of FBS, HbA1c, HOMA-IR, triglyceride, cholesterol, LDL, BUN, creatinine, urea, SGOT, SGPT, IL-1β, IL-6, IFNγ, insulin, glucagon, the abundance of Prevotella and Bacteroides fragilis group, as well as the concentration of Firmicutes spp. showed significant decrease (P < 0.01), and HDL level, Akkermansia muciniphila and Roseburia spp. abundance, and Bacteroidetes and Bifidobacterium spp. concentration showed significant increase (P < 0.0001). The observed pattern continued or remained stable at F12 for all of these variables. IL-10 and TGF-β1 remained unchanged until F3 and showed a significant drop at F12. At F3, Clostridium cluster IV increased significantly and remained at that level afterward. Moreover, concentration of Phylum Actinobacteria showed an initial drop at F3 and a later increase at F12 (P < 0.0001).

CONCLUSION

LSG is associated with a significant improvement in serum biomarkers, as well as significant changes in fecal microbiota. Future systems biology analyses would shed more light on the underlying interactions of these parameters, and could help in developing novel diagnostic and therapeutic strategies for obesity management.

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.

Evaluation of Micronutrient Status Post Laparoscopic Sleeve Gastrectomy: an Australian Perspective

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is a type of bariatric technique that has comparable outcomes to Roux-en-Y gastric bypass, the current gold standard. However, it can be associated with nutritional deficiencies postoperatively. The aim of this study was to evaluate micronutrient status post LSG.

METHODS

This is a retrospective study of 565 patients who underwent an LSG from January 2015 to September 2018. Patients lost to follow-up at 3, 6 and 12 months were 6.3%, 18.6% and 32.4%, respectively. Follow-up of the patients included regular dietetic input and micronutrient supplementation. Data that was collected included both anthropometry and nutritional markers.

RESULTS

The mean preoperative weight and body mass index (BMI) were 118.13 ± 25.36 kg and 42.40 ± 7.66 kg/m², respectively. Statistically, significant reductions in anthropometric parameters including weight, BMI (30.50 kg/m²), total weight loss (28.03%), excess weight loss (72.03%) and BMI loss (12.32 kg/m²) were observed at all timepoints up to 12 months follow-up. At 12 months, there were significant increases in 25-OH vitamin D with the incidence of deficiency decreasing from 45.7 to 15.0% compared to baseline. The incidence of hyperparathyroidism also decreased from 32.2 to 18.9% compared to baseline, and incidence of folate deficiency increased from 7.7 to 19.2%. Other nutritional parameters including calcium, iron, ferritin, vitamin B12, holotranscobalamin (active B12) and haemoglobin did not significantly change.

CONCLUSIONS

Modest effects on micronutrient status were observed in the 12-month postoperative period. Of clinically significant, de novo folate deficiencies increased, and vitamin D deficiency and hyperparathyroidism decreased. Thus, optimizing postoperative micronutrient status is imperative following LSG.

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.

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.

Recommendations Based on Evidence by the Andalusian Group for Nutrition Reflection and Investigation (GARIN) for the Pre- and Postoperative Management of Patients Undergoing Obesity Surgery

In order to develop evidence-based recommendations and expert consensus for nutrition management of patients undergoing bariatric surgery and postoperative follow-up, we conducted a systematic literature search using PRISMA methodology plus critical appraisal following the SIGN and AGREE-II procedures. The results were discussed among all members of the GARIN group, and all members answered a Likert scale questionnaire to assess the degree of support for every recommendation. Patients undergoing bariatric surgery should be screened preoperatively for some micronutrient deficiencies and treated accordingly. A VLCD (Very Low-Calorie Diet) should be used for 4-8 weeks prior to surgery. Postoperatively, a liquid diet should be maintained for a month, followed by a semi-solid diet also for one month. Protein requirements (1-1.5 g/kg) should be estimated using adjusted weight. Systematic use of specific multivitamin supplements is encouraged. Calcium citrate and vitamin D supplements should be used at higher doses than are currently recommended. The use of proton-pump inhibitors should be individualised, and vitamin B12 and iron should be supplemented in case of deficit. All patients, especially pregnant women, teenagers, and elderly patients require a multidisciplinary approach and specialised follow-up. These recommendations and suggestions regarding nutrition management when undergoing bariatric surgery and postoperative follow-up have direct clinical applicability.

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

IMPORTANCE

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

OBJECTIVE

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

DESIGN, SETTING, AND PARTICIPANTS

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

EXPOSURES

RYGB or SG.

MAIN OUTCOMES AND MEASURES

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

RESULTS

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

CONCLUSIONS AND RELEVANCE

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

The Skeletal Consequences of Bariatric Surgery

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

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

BACKGROUND

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

OBJECTIVE

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

PARTICIPANTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

Effects of Laparoscopic Sleeve Gastrectomy on Bone Mineral Density and Bone Metabolism in Chinese Patients with Obesity

OBJECTIVE

Laparoscopic sleeve gastrectomy (LSG) is one of the most effective therapies to treat obesity. Due to a lack of longitudinal research, we explored the changes in BMD and bone metabolism in Chinese patients with obesity before and after LSG.

MATERIALS AND METHODS

A total of 49 obese Chinese patients with obesity were recruited from the Second Xiangya Hospital of Central South University. All patients underwent LSG, and the metabolic indicators were evaluated, including the serum osteocalcin (OC), total-terminal propeptide of type I procollagen (TPINP) and carboxy terminal telopeptide of collagen type I (CTX) levels at baseline and 2, 6 and 12 months postoperatively. Dual energy X-ray absorptiometry (DEXA) was used to measure body composition and BMD before and 12 months after LSG.

RESULTS

The body mass index (BMI) significantly decreased at 12 months postoperatively, and no patients developed osteoporosis. The BMD of femoral neck and total hip significantly decreased from the baseline to 12 months postoperatively, while the BMD of lumbar spine did not change significantly. The OC, TPINP and CTX levels significantly increased at 12 months postoperatively. The excess BMI loss (EBMIL) was positively related while the reduction in visceral adipose tissue (VAT) mass was negatively related to the decreases in BMD of the femoral neck and total hip at 12 months postoperatively. The increase in OC was negatively correlated with the decrease in BMD of the femoral neck, while the increase in TPINP was positively correlated with the decrease in BMD of total hip.

CONCLUSION

Based on the 12-month follow-up results, the BMD of the femoral neck and total hip was decreased in Chinese patients with obesity after LSG, while bone remodelling was active. This finding suggested that weight loss, a decrease in the VAT mass and an increase in bone remodelling may be correlated with a reduction in BMD.

Nutritional Deficiencies in Severe Obesity: a Multiethnic Asian Cohort

BACKGROUND

Micronutrient deficiencies are highly prevalent in patients seeking metabolic-bariatric surgery (MBS), although literature remains scant in Asia. In this study, we assess the prevalence of nutritional deficiencies in patients with clinically severe obesity in Singapore and examine factors associated with the deficiencies.

METHODS

This is a prospective, observational study of 577 consecutive patients scheduled to undergo MBS. Nutritional profile including renal panel, calcium, phosphate, intact parathyroid hormone (iPTH), 25-hydroxyvitamin D (25(OH)D), vitamin B12, folate, ferritin, iron studies, hemoglobin, albumin, and alkaline phosphatase were analyzed.

RESULTS

Mean age was 40.6 ± 10.3 years, 61.2% female, and mean BMI 42.4 ± 8.4 kg/m². 92.9% had suboptimal vitamin D levels; of which 25.6% had vitamin D insufficiency (25(OH)D < 30 mcg/L), 57.5% had vitamin D deficiency (25(OH)D < 20 mcg/L), and 9.8% had severe vitamin D deficiency (25(OH)D < 10 mcg/L). Younger age, female gender, and higher BMI were independent factors associated with lower 25(OH)D. There was an inverse relationship between iPTH and 25(OH)D, with an inflection point at 25(OH)D of approximately 20 mcg/L. Folate deficiency was present in 31% and vitamin B12 deficiency in 9.5% of the cohort. Serum ferritin levels were low in 29.3%. 25(OH)D, ferritin, serum iron, and albumin were also significantly higher in Chinese compared to Malay and Indian patients.

CONCLUSION

Vitamin D deficiency was the most common micronutrient deficiency observed in this multi-ethnic Asian cohort presenting for MBS. Ethnic differences in nutritional status were observed.

Nutritional Deficiencies in Patients with Severe Obesity before Bariatric Surgery: What Should Be the Focus During the Preoperative Assessment?

BACKGROUND

Nutritional deficiencies are a well-recognized long-term complication following bariatric surgery. The presence of preoperative deficiencies has been shown to be predictive of postoperative deficiencies.

OBJECTIVE

The aim of the study was to investigate the prevalence of micronutrient deficiency in a large sample of patients with severe obesity preoperatively, and to determine whether such deficiencies may be related to patient's sex, body mass index, or ethnic subgroup.

DESIGN

A cross-sectional study of data collected at the time of the preoperative evaluation.

PARTICIPANTS/SETTING

Data were collected during the preoperative evaluation of 872 bariatric surgery candidates in a university hospital in Israel between 2011 and 2018. The patients were 72.9% women, with a mean age of 37.9±12.1 years and mean body mass index of 42.4±4.7 MAIN OUTCOME MEASURES: Nutritional deficiencies according to blood assays. Data on anthropometrics, comorbidities, and demographic characteristics was also collected.

STATISTICAL ANALYSES

Baseline differences between patient subgroups were analyzed using independent-samples t test, analysis of variance, or χ² test.

RESULTS

Deficiencies of vitamin D, iron, folate, vitamin B-12, elevated parathyroid hormone and low transferrin saturation were present in 75.2%, 42.6%, 28.5%, 8.5%, 35.5%, and 70% of patients, respectively. Nutritional deficiencies were significantly more common among women compared with men for iron (45.9% vs 33.5%; P=0.002), low transferrin saturation (77.7% vs 44.6%; P<0.001), vitamin D (77.5% vs 69.2%; P=0.019) and elevated parathyroid hormone level (39.5% vs 22.9%; P=0.002). Iron, transferrin saturation, and vitamin D deficiencies were more prevalent in Arab patients compared with Jewish patients: 59.6% vs 36%; P<0.001, 80.2% vs 62.8%; P=0.003, and 85.1% vs 71.6%; P<0.001, respectively. Vitamin D and iron deficiency were more common among higher body mass index subgroups (P=0.004 and P=0.040, respectively).

CONCLUSIONS

The results indicate a high prevalence of nutritional deficiencies, mainly of iron and vitamin D in bariatric surgery candidates. Patients at higher risk for nutritional deficiencies include those with higher body mass index, women, and Arabs.

The effect of excessive fat tissue on the measure of bone mineral density by dual X-ray absorptiometry: the impact of substantial weight loss following sleeve gastrectomy

PURPOSE

Dual-energy X-ray absorptiometry (DXA) is used in clinical routine to determine areal bone mineral density (aBMD). However, it is not clear whether excessive fat mass or substantial weight loss modify the aBMD measurements. The aim of this study was to evaluate the effect of soft tissue composition on aBMD measured by DXA using a clinical model (i.e. sleeve gastrectomy: SG) that induces substantial body weight loss.

METHODS

Areal bone mineral density and body composition (fat mass: FM and lean tissue mass: LTM) were determined by DXA in 41 obese patients (33 women, 80.5%) just before SG and 1 month later.

RESULTS

One month after SG, mean weight loss was -9.8 ± 2.6 kg, with a significant decrease in LTM and FM (kg) ranging from -7.3% to -9.5%. The relative variation in aBMD was increased at the lumbar spine (2.45 ± 3.44%) and decreased at the hip (-1.47 ± 2.28%), whereas no variation was observed for the whole body and radius. The variation in aBMD at the lumbar spine was inversely correlated with variations in weight, whole-body FM and trunk FM, but not LTM.

CONCLUSION

This study shows evidence of a potential effect of body composition, particularly FM, on aBMD. However, given the modest change in aBMD, which was close to the precision error of aBMD measurements, it appears that significant weight loss does not have a clinically significant impact on the evaluation of aBMD using DXA.

Fibroblast growth factor 23 levels decline following sleeve gastrectomy

OBJECTIVE

Levels of fibroblast growth factor 23 (FGF23) have been positively associated with measures of adiposity, cardiovascular disease and mortality. It is unclear whether the relationship of FGF23 with cardiovascular disease and mortality is confounded by obesity. We aimed to determine whether FGF23 concentrations decline following a reduction in adiposity after sleeve gastrectomy (SG).

DESIGN

The effect of SG on FGF23 was evaluated in 22 obese adults (59% male) with type 2 diabetes. Fat mass, weight, BMI, plasma intact FGF23, parathyroid hormone (PTH) and leptin were determined at baseline and at 12 months following SG.

RESULTS

At baseline, median (IQR) age was 51 (43-54) years, fat mass 47.8 (41.0-59.4) kg, BMI 40.9 (36.9-46.9) kg/m² and FGF23 66.2 (55.3-82.9) pg/mL. Significant changes in median BMI (-10.8 kg/m² , 95% CI: -12.9 to -7.2, P < 0.0001), fat mass (-20.0 kg, 95% CI: -26.7 to -12.4, P < 0.0001) and weight (-34.7 kg, 95% CI -40.0 to -23.1, P < 0.0001) were observed after SG. FGF23 (-12.4 pg/mL, 95% CI: -19.5 to 2.0, P = 0.005), PTH (-1.1 pmol/L, 95% CI: -1.7 to 0.2, P = 0.009) and leptin (-1687 pg/mL, 95% CI -4524 to -563, P = 0.01) declined following SG. Change in FGF23 was not significantly associated with change in measures of adiposity, PTH or leptin.

CONCLUSIONS

FGF23 concentrations decline in the setting of significant weight loss following SG, implying that increased FGF23 concentrations are a downstream consequence of obesity, which may confound its association with cardiometabolic dysfunction. Mediators of the relationship between adiposity and FGF23 require further elucidation.

Changes in bone mineral density and bone metabolism after sleeve gastrectomy: a systematic review and meta-analysis

BACKGROUND

Roux-en-Y gastric bypass surgery adversely affects bone health. The evidence is less well-described for sleeve gastrectomy (SG).

OBJECTIVES

To better characterize bone metabolism changes after SG.

SETTING

Systematic review and meta-analysis.

METHODS

MEDLINE and EMBASE were searched through March 2019 for eligible studies assessing adults with obesity aged 18 years or older that underwent SG. Bone mineral density (BMD), serum calcium, serum phosphate, serum 25-hydroxyvitamin D, serum parathyroid hormone, or serum alkaline phosphatase were reported at baseline and after SG; and a follow-up duration was at least 6 months. Preoperative and postoperative mean of each outcome of interest and corresponding standard deviations were extracted from each study and the mean difference (MD) was calculated. Pooled MD was then calculated by combining MDs of each study using random-effects model.

RESULTS

A total of 22 studies with 1905 patients with obesity that underwent SG were included. There were significant decreases in total hip BMD (pooled MD of -.06 g/cm²; 95% confidence interval -.09 to -.03; I² = 0%) and femoral neck BMD (pooled MD of -.05 g/cm²; 95% confidence interval -.09 to -.02; I² = 0%) after SG. No significant change in lumbar spine BMD was observed. There were significant increases in serum calcium, serum 25-hydroxyvitamin D, and serum phosphate. Serum parathyroid hormone was significantly decreased. Serum alkaline phosphatase was not significantly altered after SG.

CONCLUSIONS

The present study found a decreased BMD among patients with obesity after SG.

Alterations in Fat Mass and Bone Mineral Density Are Associated with Decreased Lipocalin-2 After Laparoscopic Sleeve Gastrectomy in Obese Chinese Women

OBJECTIVE

Lipocalin-2 (LCN2) plays an important role in the regulation of the obesity and obesity-related dysmetabolic state. This study aimed to analyze serum LCN2 level in Chinese women with obesity before and after laparoscopic sleeve gastrectomy (LSG) and determine the association between alteration in fat mass and bone mineral density (BMD) and LCN2 level.

METHODS

Fifty-two women (38 patients with obesity and 14 with normal body mass index (BMI)) were enrolled in this study. All patients with obesity underwent LSG. BMDs of the arm, leg, thoracic and lumbar spine, and pelvis were measured by dual-energy X-ray absorptiometry. Body fat mass and distribution were measured by dual-energy X-ray absorptiometry, and routine anthropometric/laboratory biochemical parameters at baseline and 3 and 12 months after LSG were recorded. Serum LCN2 levels were measured using an enzyme-linked immunosorbent assay.

RESULTS

Serum LCN2 level was significantly higher in women with obesity than in the controls with normal BMI (102.70 ± 27.19 vs. 80.66 ± 19.55 ng/mL, P = 0.009). LCN2 level was decreased at 3 and 12 months after LSG (86.73 ± 26.79 ng/mL, P = 0.171, and 64.79 ± 28.39 ng/mL, P < 0.001, respectively). LSG led to marked body fat mass and slight BMD decrease. Decreased LCN2 level was significantly correlated with alterations in left and right leg BMDs and trunk fat mass at 12 months after LSG.

CONCLUSIONS

Obesity was associated with up-regulated serum LCN2 level. Decreased LCN2 level was positively correlated with changes in BMD and fat mass at 12 months after LSG in Chinese women.

Vitamin D deficiency in relation to general and abdominal obesity among high educated adults

PURPOSE

To assess the association of vitamin D deficiency with general and abdominal obesity among high educated Iranian adults.

METHODS

Current cross-sectional study was done on 500 Iranian professors aged 35 years or more. Complete data on general and abdominal obesity as well as serum 25(OH)D concentrations were available for 352 persons. Obesity was considered as body mass index ≥ 30, and abdominal obesity as waist circumference ≥ 80 cm for women and ≥ 94 cm for men. Furthermore, vitamin D deficiency was defined as serum 25(OH)D < 30 ng/ml.

RESULTS

Mean age of study population was 53.03 ± 7.15 years. Compared with those in the first quartile of serum 25(OH)D, participants in the fourth quartile were less likely to be generally obese (OR 0.46, 65% CI 0.22-0.99). Such finding was also seen even after taking potential confounders into account. Furthermore, we found an inverse association between serum 25(OH)D and abdominal obesity in fully adjusted model (OR 0.44, 95% CI 0.22-0.86). In addition, a significant positive association was found between vitamin D deficiency and obesity; such that after controlling for potential confounders, participants with vitamin D deficiency had 2.16 and 2.04 times greater odds for having general (OR 2.16, 95% CI 1.05-4.45) and abdominal obesity (OR 2.04, 95% CI 1.16-3.60), respectively, than those with normal levels of vitamin D.

CONCLUSION

Serum 25(OH)D concentrations were inversely associated with general and abdominal obesity. In addition, vitamin D deficiency was positively associated with both general and abdominal obesity.

LEVEL OF EVIDENCE

Level V, cross-sectional descriptive study.

CHANGES IN BONE MINERAL PARAMETERS AFTER SLEEVE GASTRECTOMY: RELATIONSHIP WITH GHRELIN AND PLASMA ADIPOKINE LEVELS

CONTEXT

Metabolic surgery is currently the most efficient treatment for obesity, but concern is raised about the possible long-term nutritional side effects. Bone metabolism is often adversely affected after surgery, but literature data are contradictory.

OBJECTIVE

The aim of this study was to evaluate the evolution of bone mass parameters in the first year after laparoscopic sleeve gastrectomy in relation to anthropometric and body composition parameters and specific hormones of obesity.

DESIGN

We conducted a prospective study on 75 patients with obesity that underwent metabolic surgery over a course of 18 months at our center, with a follow-up period of 12 months.

SUBJECTS AND METHODS

All patients underwent a complex preoperative assessment and were required to return for medical follow-up at 6 and 12 months after surgery. Each visit included anthropometric parameters, DEXA and determination of specific hormonal parameters.

RESULTS

We noticed a significant improvement in anthropometric and body composition parameters after surgery. The value of adiponectin presented a significant increase after surgery and leptin showed a significant decrease at 6 and 12 months postoperative; ghrelin level decreased postoperative compared to preoperative, but without statistical significance. We observed no reduction in BMD after surgery, but a significant improvement in BMC at 12 months after surgery compared to preoperative. Ghrelin negatively correlated to BMD preoperative.

CONCLUSIONS

Despite the significant alterations in anthropometric, body composition and hormonal parameters, we found no negative effect on BMD and BMC in our study population.

Calcium absorption may be affected after either sleeve gastrectomy or Roux-en-Y gastric bypass in premenopausal women: a 2-y prospective study

Background

Although Roux-en-Y gastric bypass (RYGBP) is known to reduce calcium absorption (CA), the effects of vertical sleeve gastrectomy (SG) and its long-term implications on CA have not yet been studied.

Objective

The aim of this study was to evaluate changes in CA and its relation with modifications of bone mineral density (BMD), intakes of calcium and vitamin D, vitamin D status, and parathyroid hormone (PTH) concentrations ≤24 mo after SG and RYGBP, respectively.

Design

Twenty-six premenopausal women undergoing SG [mean ± SD body mass index (BMI; kg/m2): 37.3 ± 3.2; age: 34.2 ± 10.2 y] and 32 undergoing RYGBP (BMI: 42.0 ± 4.2; age: 37.3 ± 8.1 y) were studied at baseline (presurgery) and followed up at 12 and 24 mo after surgery. BMD, bone alkaline phosphatase activity, and serum PTH, 25-hydroxyvitamin D [25(OH)D], calcium, magnesium, and phosphorus concentrations were determined. Food and supplement intakes were recorded. CA was measured by using a dual stable isotope method.

Results

In premenopausal women, CA was significantly reduced from 36.5% ± 2.0% preoperatively to 21.0% ± 2.3% and 18.8% ± 3.4% at 12 and 24 mo post-SG surgery, respectively. CA also decreased significantly from 41.5% ± 2.8% preoperatively to 27.9% ± 3.8% and 18.5% ± 2.2% 12 and 24 mo after RYGBP, respectively. No difference was found between type of surgery (time × group interaction, P = 0.60). Considering both groups combined, 56.6% of the variance in CA at the 12-mo but not at the 24-mo follow-up was explained by serum PTH and 25(OH)D concentrations, together with vitamin D and calcium intakes.

Conclusions

CA was similarly reduced in both SG and RYGBP compared with baseline, and it was not associated with changes in BMD or body weight loss. This reduction in CA could be explained only partially by calcium intake increase. This trial is registered at http://www.isrctn.com as ISRCTN31937503.

Obesity and bone metabolism

The interaction between obesity and bone metabolism is complex. The effects of fat on the skeleton are mediated by both mechanical and biochemical factors. Though obesity is characterized by higher bone mineral density, studies conducted on bone microarchitecture have produced conflicting results. The majority of studies indicate that obesity has a positive effect on skeletal strength, even though most likely the effects are site-dependent and, in fact, obese individuals might be at risk of certain types of fractures. Mechanical loading and higher lean mass are associated with improved outcomes, whereas systemic inflammation, observed especially with abdominal obesity, may exert negative effects. Weight loss interventions likely lead to bone loss over time. Pharmacological treatment options seem to be safe in terms of skeletal health; however, the skeletal effects of bariatric surgery are dependent on the type of surgical procedure. Malabsorptive procedures are associated with higher short-term adverse effects on bone health. In this narrative review, we discuss the effects of obesity and weight loss interventions on skeletal 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.

Protocol for a 1-year prospective, longitudinal cohort study of patients undergoing Roux-en-Y gastric bypass and sleeve gastrectomy: the BARI-LIFESTYLE observational study

INTRODUCTION

Roux-en-Y gastric bypass and sleeve gastrectomy are the two most common bariatric surgery performed in the UK that result in comparable weight loss and remission of obesity-associated comorbidities. However, there is a paucity of studies examining the impact of these procedures on body composition, physical activity levels, sedentary behaviour, physical function and strength, dietary intake, health-related quality of life and costs.

METHODS AND ANALYSIS

The BARI-LIFESTYLE observational study is a 1-year prospective, longitudinal cohort study within a real-world routine clinical care setting aiming to recruit 100 patients with severe obesity undergoing either primary Roux-en-Y gastric bypass or sleeve gastrectomy from two bariatric centres in London, UK. Participants will be followed up four times during the study period; presurgery baseline (T0) and at 3 (T1), 6 (T2) and 12 months (T3) postsurgery. In addition to the standard follow-up investigations, assessments including dual-energy X-ray absorptiometry scan, bioelectric impedance analysis, 6 min walk test, sit-to-stand test and handgrip test will be undertaken together with completion of questionnaires. Physical activity levels and sedentary behaviour will be assessed using accelerometer, and dietary intake will be recorded using a 3-day food diary. Outcome measures will include body weight, body fat mass, lean muscle mass, bone mineral density, physical activity levels, sedentary behaviour, physical function and strength, dietary intake, health-related quality of life, remission of comorbidities, healthcare resource utilisation and costs.

ETHICS AND DISSEMINATION

This study has been reviewed and given a favourable ethical opinion by London-Dulwich Research Ethics Committee (17/LO/0950). The results will be presented to stakeholder groups locally, nationally and internationally and published in peer-reviewed medical journals. The lay-person summary of the findings will be published on the Centre for Obesity Research, University College London website (http://www.ucl.ac.uk/obesity).

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.

Thin bones: Vitamin D and calcium handling after bariatric surgery

Bariatric surgery has proven to be a valuable treatment option for morbid obesity. However, these procedures can lead to impaired intestinal absorption of calcium and vitamin D, thereby challenging calcium homeostasis and possibly contributing to bone loss leading to an increased fracture risk. Besides calcium and vitamin D malabsorption, hormonal changes occurring after surgery can also be the source of observed bone loss. In this review, first, a case report will be discussed, highlighting the relevance of this topic. Afterwards, changes in bone density and fracture risk, after the two most performed types of bariatric surgery, Sleeve Gastrectomy (SG) and Roux-en-Y Gastric Bypass (RYGB) will be discussed. In addition, we discuss the putative underlying mechanisms leading to bone changes based on both preclinical and clinical observations. Nonetheless, it is clear further research is needed to further elucidate the exact mechanisms of bone loss following bariatric surgery and subsequently identify potential treatment options for bone preservation.

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Bariatric surgery induces bone loss and leads to increased fracture risk.

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Bone resorption increases after both SG and, more strongly, after RYGB.

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Malabsorption and adipose tissue-related hormones likely contribute to bone loss.

Vitamin D Metabolism in Bariatric Surgery

Hypovitaminosis D is common in obese patients and persists after roux-en-Y gastric bypass and sleeve gastrectomy. Several societies recommend screening for vitamin D deficiency before bariatric surgery, and replacement doses of 3000 IU/d and up to 50,000 IU 1 to 3 times per week, in case of deficiency, with periodic monitoring. These regimens are mostly based on expert opinion. Large trials are needed to assess the vitamin D dose response, by type of bariatric surgery, and evaluate the effect on surrogate markers of skeletal outcomes. Such data are essential to derive desirable vitamin D levels in this population.

Investigating Nutritional Deficiencies in a Group of Patients 3 Years Post Laparoscopic Sleeve Gastrectomy

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) as a single-stage procedure has shown to be effective in achieving significant weight loss and resolving obesity-related co-morbidities. However, its nutrition consequences have not been extensively explored. This study aims to investigate weight loss and evolution of nutritional deficiencies in a group of patients 3 years post LSG.

METHODS

Retrospective data of a group of patients, 3 years following LSG as a stand-alone procedure was collected. Data included anthropometry, nutritional markers (hemoglobin, iron studies, folate, calcium, iPTH, vitamins D, and B₁₂), and compliancy with supplementations.

RESULTS

Ninety-one patients (male/female; 28:63), aged 51.9 ± 11.4 years with a BMI of 42.8 ± 6.1 kg/m² were identified to be 3 years post LSG. Percentage of weight loss at 1 and 3 years post-operatively was 29.8 ± 7.0 and 25.9 ± 8.8 %, respectively. Pre-operatively, the abnormalities included low hemoglobin (4 %), ferritin (6 %), vitamin B₁₂ (1 %), vitamin D (46 %), and elevated iPTH (25 %). At 3 years post-operatively, the abnormal laboratory values included low hemoglobin (14 % females, P = 0.021), ferritin (24 %, P = 0.011), vitamin D (20 %, P = 0.018), and elevated iPTH (17 %, P = 0.010). Compliancy with multivitamin supplementation was noted in 66 % of patients.

CONCLUSION

In these patients, LSG resulted in pronounced weight loss at 1 year post-operatively, and most of this was maintained at 3 years. Nutritional deficiencies are prevalent among patients prior to bariatric surgery. These deficiencies may persist or exacerbate post-operatively. Routine nutrition monitoring and supplementations are essential to prevent and treat these deficiencies.

A Systematic Review: Vitamin D Status and Sleeve Gastrectomy

BACKGROUND

Bariatric patients regularly present with insufficient vitamin D status before and after surgery, which requires substantial supplementation to treat. This review aims to assess the effect of sleeve gastrectomy on vitamin D status and the effectiveness of vitamin D supplementation.

METHODS

This review was conducted in accordance with the Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies.

RESULTS

The current guidelines recommend initial vitamin D supplementation of at least 3000 IU/day post-operatively, with no need for follow-up testing after sleeve gastrectomy. Only one study has trialled a dose in line with the recommendations for this patient group. They found that it was effective in improving VitD status.

CONCLUSIONS

On-going monitoring of vitamin D status is necessary, as the recommended level is not often reached.

Outcomes of laparoscopic sleeve gastrectomy in elderly obese Japanese patients

AIM

Laparoscopic sleeve gastrectomy (LSG) has proven to be the most effective strategy for the treatment of morbid obesity, however its efficacy and safety in an aging population has not yet been confirmed. In this study, we evaluated the effectiveness and safety of LSG in elderly obese Japanese patients.

METHODS

Three obese individuals aged >60 years and 11 obese individuals aged <60 years who underwent LSG were enrolled. Pre- and postoperative changes after at least 12 months were examined, including bodyweight, body mass index, total weight loss, excess weight loss, bone mineral density and bone-related markers.

RESULTS

There were no significant differences between patients aged <60 years and >60 years in terms of percent total weight loss (24.4 ± 11 vs 23 ± 4.4%, respectively) and percent excess weight loss (49.1 ± 23.4 vs 47.6 ± 10 %, respectively). Dual-energy X-ray absorptiometry was carried out before and 12 months after LSG. There were no significant differences in bone mineral density changes at the lumbar spine and femoral neck between the two groups (0.01 ± 0.06 vs 0.02 ± 0.03 g/cm² , -0.03 ± 0.06 vs -0.08 ± 0.02 g/cm² , respectively). There were no peri- and postoperative complications. All three patients aged >60 years had reduced bone mineral density in the femoral neck after LSG; one was diagnosed with osteoporosis.

CONCLUSIONS

Although the present results suggest that LSG could be of considerable benefit to elderly obese Japanese patients, long-term careful observation after bariatric surgery is especially important in elderly patients to prevent future osteoporosis. Geriatr Gerontol Int 2017; 17: 2068-2073.

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.

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.

Markers of Bone Metabolism in Obese Individuals Undergoing Laparoscopic Sleeve Gastrectomy

BACKGROUND

Besides its advantages, bariatric surgery implicates a risk of nutritional deficiencies, which might result in impaired bone metabolism. We assessed the effect of laparoscopic sleeve gastrectomy (LSG) on blood markers of bone metabolism in obese patients during a 3-year observation period.

METHODS

In 39 obese patients (29 women, 10 men, mean BMI 51.8 ± 6.8 kg/m(2)) undergoing LSG, we measured blood concentrations of 25-hydroxyvitamin D (25(OH)D), calcium, parathyroid hormone (PTH), bone alkaline phosphatase (BAP), and N-telopeptides crosslinks (NTx) before LSG and up to 3 years postoperatively. Vitamin D and calcium supplementations were recorded.

RESULTS

LSG caused an excess weight loss (EWL) of 54 ± 20 % after 3 years. Before surgery, we found decreased levels of 25(OH)D and calcium in 80 and 5 % of the subjects, respectively, while increased levels of PTH, BAP, and NTx were found in 39, 28, and 21 %, respectively. Mean levels of NTx and the prevalence of elevated levels of NTx increased within 2 years (p < 0.001 and p < 0.01). Neither mean blood concentrations of 25(OH)D, calcium, PTH, and BAP nor relative prevalence of deficiencies regarding these markers changed during the study period. The supplementation rates of calcium and vitamin D increased postoperatively.

CONCLUSIONS

Morbid obesity is associated with pronounced changes of markers of bone metabolism; LSG did neither aggravate nor ameliorate vitamin D metabolism within a 3-year time period, but led to increased bone resorption 2 years postoperatively. Routine supplementation of calcium and vitamin D is not likely sufficient to compensate the obesity-associated deficiencies in bone metabolism.

The effects of bariatric surgery on bone and nephrolithiasis

The impact of bariatric surgery on cardiovascular and diabetic complications associated with an improvement in survival has overshadowed the adverse skeletal health and development of kidney stone disease in this population. All longitudinal based studies in the literature reporting the incidence of bone fractures or kidney stones following bariatric surgery were reviewed. Moreover, all publications over the past decade which assessed changes in bone mineral density and bone quality, or explored underlying pathophysiologic mechanisms of bone and kidney stone disease were carefully reviewed. This review provides sufficient data to support that osteoporotic fractures and kidney stone disease are associated with Roux-en-Y gastric bypass surgery. However, due to the limited data available to date, no definitive conclusion could yet be drawn whether sleeve gastrectomy or adjustable gastric banding is associated with bone fractures and kidney stones. Bariatric surgery has emerged as the most effective and sustained treatment for weight reduction. This treatment modality has been recognized to diminish the risk of cardiovascular morbidity and mortality and ameliorate diabetes mellitus complications. The derangement in mineral metabolism has emerged as a major complication following bariatric surgery.