Thin bones: Vitamin D and calcium handling after bariatric surgery

Bone health following paediatric and adolescent bariatric surgery: a systematic review and meta-analysis

Background

Childhood obesity is a pressing health crisis of epidemic proportions. Bariatric surgery (BS) is an effective weight loss solution however its role in the paediatric population is contentious owing to the paucity of weight specific and generalised health outcomes. This systematic review and meta-analysis aimed to assess the impact of paediatric BS on bone health.

Methods

This prospectively registered systematic review (PROSPERO ID: CRD42023432035) was performed in accordance with PRISMA guidelines. We searched MEDLINE (1946-1928 September 2023), EMBASE (1947-1928 September 2023) via the Ovid platform, and the Cochrane Review Library to identify scientific publications reporting bone outcome measures in patients under the age of 18 years who underwent BS. Meta-analysis was undertaken on post-operative weight and bone parameters in paediatric patients following BS. Outcomes were reported as weighted or standardized mean difference with 95 percent confidence intervals. Subgroup analysis by intervention, quality scoring and risk of bias were assessed.

Findings

Twelve studies with 681 patients across 5 countries (mean age 17 ± 0.57 years) were included. The quality of included studies was rated as high and there was substantial between-study heterogeneity for most factors included in the meta-analysis (I2 from 0% to 99.1%). Patients underwent Roux-en-Y gastric bypass (RYGB, n = 216), sleeve gastrectomy (SG, n = 257), gastric band (n = 184) or intragastric balloon placement (n = 24). BS was associated with significant weight reduction, body mass index (BMI) -12.7 kg/m2 (95% CI -14.5 to -10.9, p < 0.001), with RYGB being most effective, BMI -16.58 kg/m2 (95% CI -19.6 to -13.6, p < 0.001). Patients who underwent SG or RYGB had significantly lower lumbar bone mineral density, -0.96 g/cm2 (95% CI -0.1 to -0.03, p < 0.001), Z score, -1.132 (95% CI -1.8 to -0.45, p < 0.001) and subtotal body bone mineral density, -0.7 g/cm2 (95% CI -1.2 to -0.2, p < 0.001) following surgery. This was accompanied with higher markers of bone resorption, C-terminal telopeptide of type 1 collagen 0.22 ng/ml (95% CI 0.12-0.32, p < 0.001) and osteocalcin, 10.83 ng/ml (95% CI 6.01-15.67, p < 0.001). There was a significant reduction in calcium levels following BS, -3.78 mg/dl (95% CI -6.1 to -1.5, p < 0.001) but no difference in 25-hydroxyvitamin D, phosphate, bone alkaline phosphatase, procollagen type 1 N propeptide or parathyroid hormone.

Interpretation

BS effectively reduces weight in paediatric patients, but RYGB and SG may have adverse effects on bone health in the medium term. It is crucial to monitor and support bone health through appropriate nutritional supplementation and judicious follow-up. Long-term data is needed to fully understand the clinical implications of these findings on bone outcomes.

Funding

Medical Research Council (MRC), United Kingdom.

Development and complications of nutritional deficiencies after bariatric surgery

The clinical effectiveness of bariatric surgery has encouraged the use of bariatric procedures for the treatment of morbid obesity and its comorbidities, with sleeve gastrectomy and Roux-en-Y gastric bypass being the most common procedures. Notwithstanding its success, bariatric procedures are recognised to predispose the development of nutritional deficiencies. A framework is proposed that provides clarity regarding the immediate role of diet, the gastrointestinal tract and the medical state of the patient in the development of nutritional deficiencies after bariatric surgery, while highlighting different enabling resources that may contribute. Untreated, these nutritional deficiencies can progress in the short term into haematological, muscular and neurological complications and in the long term into skeletal complications. In this review, we explore the development of nutritional deficiencies after bariatric surgery through a newly developed conceptual framework. An in-depth understanding will enable the optimisation of the post-operative follow-up, including detecting clinical signs of complications, screening for laboratory abnormalities and treating nutritional deficiencies.

Vitamin D Concentration Changes after Bariatric Surgery

Introduction

Bariatric surgery causes physiological and anatomical changes in the gastrointestinal tract that interfere with intestinal absorption and, consequently, with the nutritional status, especially about vitamin D. The aim of the study was to evaluate the vitamin D levels and body composition of these patients in the Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) types of surgery.

Methods

The retrospective cohort study included a population of 120 patients aged between 18 and 65 years, with class II or III obesity, undergoing bariatric surgery procedures (VSG or RYGB-type). Data were collected on the degree of obesity, age, average time since surgery, and gender. The individuals underwent a complete physical examination, measuring blood pressure, weight, height, waist, and neck circumference. In addition to calculating the percentage of loss of body weight and assessing body fat, the food frequency and physical activity of these patients were evaluated. Blood was collected, and the insulin variables, hydroxyvitamin D (25OHD), were analyzed.

Results

There was a significant difference between groups only for PTH, total BMD, and insulin variables. A significant intragroup difference was found in the variables' body mass index (BMI) and vitamin D for the vertical sleeve gastrectomy group and BMI for the RYGB group.

Conclusion

The analysis between the groups of procedures, similarity in body composition and postsurgical vitamin D levels, with significant differences only for PTH, BMD, and insulin variables, demonstrates that both procedures are effective in reducing fat mass.

Hypocalcaemia following thyroidectomy among patients who have previously undergone bariatric surgery: systematic review and meta-analysis

BACKGROUND

Hypocalcaemia is a common complication after thyroidectomy. Bariatric surgery is associated with significant changes in calcium metabolism. Some studies have identified bariatric surgery as a risk factor for hypocalcaemia after thyroidectomy. This systematic review and meta-analysis assessed whether a history of bariatric surgery was associated with an increased risk of hypocalcaemia after thyroidectomy.

METHODS

This prospectively registered systematic review (PROSPERO; CRD42021295423) was performed in accordance with PRISMA guidelines. Meta-analysis was undertaken using the Mantel-Haenszel method, with outcomes reported as ORs with 95 per cent confidence intervals.

RESULTS

Twenty studies were included in the qualitative synthesis. Five studies incorporating 19 547 patients met the inclusion criteria for meta-analysis, of whom 196 (1.0 per cent) had a history of bariatric surgery. Patients with a history of bariatric surgery were more likely to develop hypocalcaemia after thyroidectomy (30.6 versus 13.0 per cent; OR 3.90, 95 per cent c.i. 1.50 to 10.12; P = 0.005). Among those with a history of bariatric surgery, patients who underwent a bypass procedure were more likely to develop hypocalcaemia after thyroidectomy than those who had a restrictive procedure (38 versus 23 per cent; OR 2.12, 1.14 to 3.97; P = 0.020).

CONCLUSION

Patients with a history of bariatric surgery have a significantly greater risk of hypocalcaemia after thyroidectomy, with a heightened risk among those who have had a bypass procedure. Surgeons performing thyroid surgery should be aware of the increased risk of hypocalcaemia after thyroidectomy among these patients.

Changes in Sex Steroids and Enteric Peptides After Sleeve Gastrectomy in Youth in Relation to Changes in Bone Parameters

CONTEXT

Sleeve gastrectomy (SG) improves metabolic endpoints but is associated with impaired bone outcomes.

OBJECTIVE

To determine mechanisms contributing to impaired bone health in youth following SG.

METHODS

12-month longitudinal observational study in a multidisciplinary tertiary-care hospital, including 64 youth 13-25 years old with moderate-to-severe obesity (51 females); 30 underwent SG and 34 were nonsurgical (NS) controls. SG was undertaken after a combined decision-making process between treatment team and patient. The main outcome measures were fasting blood for enteric peptides, sex steroids, sclerostin, and bone turnover markers (N-terminal propeptide of type 1 procollagen [P1NP] and C-terminal cross-linking telopeptide [CTX]); dual-energy X-ray absorptiometry measures of areal bone mineral density (aBMD) and body composition; high resolution peripheral quantitative computed tomography; measures of volumetric BMD (vBMD); microfinite element analysis of strength estimates (distal radius and tibia).

RESULTS

SG had greater reductions in body mass index (BMI) z-scores, serum estrone, and the free androgen index (FAI) (P ≤ .046), and greater increases in sclerostin, P1NP, and CTX (P ≤ .010) than NS controls. Fasting ghrelin decreased in SG vs NS (P < .0001); fasting peptide YY did not change. Most changes were driven by female SG participants. Among females (the majority of study participants), after controlling for baseline age and race, reductions in total hip aBMD Z-scores were positively associated with changes in BMI, lean mass, estrone, FAI, and ghrelin, and inversely with changes in sclerostin.. Decreases in total vBMD of the radius and tibia were associated positively with decreases in BMI. Increases in CTX were associated with decreases in BMI, lean mass, and ghrelin, and increases in sclerostin.

CONCLUSION

Bone loss after SG in youth is associated with changes in body composition, sex steroids, sclerostin, and enteric peptides. These are potential targets for future preventative or therapeutic strategies.

Compliance and Patients' Perspectives Towards Nutritional Supplementation Following Bariatric Surgery

BACKGROUND

Nutritional supplementation is recommended as a prophylactic strategy for nutritional deficiencies after bariatric surgery. Little is known regarding compliance and patients' perspectives. The purpose of the study was to explore supplement intake, compliance, and patients' perspectives (including barriers, facilitators, and beliefs) and to examine whether compliance to nutritional supplementation can be predicted after bariatric surgery. MATERIAL AND METHODS: A questionnaire was developed to explore supplement intake and patients' perspectives. The Probabilistic Medication Compliance Scale (ProMAS) was included and modified to measure behaviors related to supplementation compliance. Content validity was assessed with an expert and patient panel. Consequently, a cross-sectional survey was conducted among patients that underwent bariatric surgery, who were invited using social media. Descriptive statistics and Spearman correlations were applied. Multiple linear regression analysis was performed to predict compliance.

RESULTS

A 58-item questionnaire was developed and content validated, resulting in a scale-content validity index of 0.93. The questionnaire was completed by 402 subjects. Sixty-nine subjects reported not consuming any nutritional supplement (n = 69; 17.2%). For the supplement users (n = 333; 82.8%), a median ProMAS sum score of 11.0 (7.0-15.0) was observed. Increasing age and medicine intake were positive predictors of compliance (age: B = 0.058, p = 0.01; medicine intake: B = 0.39, p < 0.001), while experiencing barriers was identified as a negative predictor of compliance (B =  - 4.637, p < 0.001). Top three barriers for supplement use were forgetfulness (n = 118; 29.4%), too expensive (n = 91; 22.6%), and experiencing side effects (n = 61; 15.2%).

CONCLUSION

Lifelong nutritional supplementation is essential after bariatric surgery, but compliance can be affected by the presence of barriers.

The Impact of Bariatric Surgery on Bone Health: State of the Art and New Recognized Links

Bariatric surgery (BS) is the most effective therapy for severe obesity, which improves several comorbidities (such as diabetes, hypertension, dyslipidemia, among others) and results in marked weight loss. Despite these consensual beneficial effects, sleeve gastrectomy and Roux-en-Y gastric bypass (the two main bariatric techniques) have also been associated with changes in bone metabolism and progressive bone loss. The objective of this literature review is to examine the impact of bariatric surgery on bone and its main metabolic links, and to analyze the latest findings regarding the risk of fracture among patients submitted to bariatric surgery.

Bariatric surgery for the management of type 2 diabetes mellitus-current trends and challenges: a review article

Obesity has become an epidemic and has emerged as a serious ailment of global concern. Longstanding obesity may lead to several complications, including type 2 diabetes mellitus (T2DM). Considering the role of the gastrointestinal tract (GIT) in glycemic control, altering it would be relevant to the T2DM management algorithm. Bariatric surgery is a well-known surgical procedure that alters the GIT for managing T2DM among moderate to severely obese patients. T2DM remissions (adequate glycemic control without any other antidiabetic drugs) among the post-bariatric patients are due to weight loss related and weight loss unrelated pathophysiological mechanisms, including caloric intake restriction, increased insulin secretion, sensitivity, and malabsorption. Evidence suggests that bariatric surgeries among T2DM patients improved micro and macrovascular complications. Bariatric surgical procedures have more advantages of post-operative weight loss and glycemic control in biliopancreatic diversions than other available bariatric surgical procedures. Several concerns raised on the short and long-term risks associated with the bariatric surgery were nutritional deficiencies, psychological issues, GIT ulcers, and survival rates. Data related to follow-up of complications related to the above-stated risk are still elusive. According to some of the recently published studies, relapse of T2DM after remission is a worrying phenomenon among post-bariatric surgery patients, requiring more clinical trials and long-term follow-up on the relapsed patients. The effectiveness of reoperation among the relapsed patients also needs to be evaluated. Other unresolved issues related to bariatric surgery are patient compliance, cost-effectiveness, quality of life among post-bariatric patients, and the effectiveness of the post-operative holistic approach to avoid relapse. Future studies, especially randomized controlled trials, are recommended to resolve the existing controversies associated with bariatric surgery.

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.

A Case Report of Severe Osteomalacia in a Young Patient After Bariatric Surgery

Obesity can promote several metabolic, cardiovascular, and musculoskeletal complications and has been associated with poor quality of life. The treatment of obesity can range from simple lifestyle modifications or medications to complicated bariatric surgeries. Although bariatric surgery has been a proven treatment for morbid obesity, it has also been associated with multiple consequences and complications. Several reports and studies have revealed bone loss or decreased bone mineral density (BMD), fractures, or even several metabolic bone diseases, such as osteoporosis, following bariatric surgery. This case report aims to increase awareness on postoperative patient supplementation compliance and incorporation of early detection and intervention. This case report involves a 39-year-old male who underwent laparoscopic biliopancreatic diversion 10 years prior to presentation. The patient was not compliant with his supplements for over nine years, which lead to multiple fragility fractures, myopathy, and muscle atrophy due to hypocalcemia, vitamin D deficiency, hyperparathyroidism, and other electrolyte disturbances. He has since been treated with supplements and physiotherapy for 10 months and showed clinical improvement. This case report highlights the importance of pre- and postoperative screening of bone loss risks and any vitamin or mineral deficiencies with subsequent correction via supplements. Moreover, it emphasizes the need for more studies on the complications of late post-bariatric surgeries.

Improving vitamin D status in bariatric surgery subjects with monthly high-dose ergocalciferol

Background: Vitamin D insufficiency is common before and after bariatric surgery. Optimal supplementation to treat vitamin D insufficiency is not clearly defined. Objective: Determine if serum 25 (OH) D levels improve by the consumption of an additional monthly ergocalciferol supplement by subjects after bariatric surgery. Study design: Thirty-two subjects were randomly divided to receive an additional 100,000 IUs of ergocalciferol monthly after bariatric surgery (n=10) or standard level vitamin D supplement after bariatric surgery (n=22). Serum 25 (OH) D, calcium, and hemoglobin A1c levels were measured preoperatively and one year after bariatric surgery. Results: Mean changes in BMI at 1-year post-operation was -18.12±6.46 kg/m² in the control group versus -18.84±4.7 kg/m²; p=0.638 in the vitamin D group. One year after bariatric surgery, the mean changes from baseline in vitamin D levels were 2.69±9.4 and 12.4±17.0 ng/mL in control and intervention groups, respectively. The treated group showed a marginally higher mean increase in Vitamin D than the control group, p=0.059. Other mean changes at 1-year post-surgery that were not significantly different include calcium -0.264±0.45 and -0.21±0.509 mg/dl in control and intervention groups, respectively and Hgb A1c -1.0±1.21 and -0.95±0.071% in control and intervention groups, respectively. Conclusion: This study showed 100,000 IUs ergocalciferol once a month is a safe and effective treatment for vitamin D insufficiency in most patients having bariatric surgery.

Micronutrients deficiences in patients after bariatric surgery

Bariatric surgery is an effective option for managing obesity and has gained general acceptance among patients in recent years. Generally, despite the high caloric intake, a bad nutritional habit of obese people results in the deficiency of several vitamins, minerals, and trace elements essential for body metabolism and normal physiological processes. Additionally, the current bariatric surgical approaches such as sleeve gastrectomy (SG), Roux-en-Y-gastric bypass (RYGB), laparoscopic adjustable gastric banding (LAGB), and jejunoileal bypass (JIB) can cause or exacerbate these deficiencies. Based on several reports, it appears that the various bariatric surgical procedures affect nutrient absorption differently. Being purely restrictive, LAGB and SG affect the absorption of iron, selenium, and vitamin B₁₂, while RYGB, JIB, and biliopancreatic diversion have a more profound impact on the absorption of essential vitamins, minerals, and trace elements. Nutritional deficiencies in vitamins, minerals, and trace elements may follow bariatric surgery and are associated with clinical manifestations and diseases, including anemia, ataxia, hair loss, and Wernicke encephalopathy. The present review summarizes some of the major vitamin and micronutrient deficiencies associated with bariatric surgery, particularly those presented post-surgically. To avoid any adverse consequences of vitamin and trace element deficiency, proper monitoring and tests are recommended at any stage, from pre- to post-surgery (periodical check-up), followed by specific and individual nutritional supplementation treatments and a proper healthy diet.

Secondary Hyperparathyroidism Among Bariatric Patients: Unraveling the Prevalence of an Overlooked Foe

INTRODUCTION

Bariatric surgery (BS) is the most effective therapeutic approach to obesity. It is associated with great gastrointestinal anatomic changes, predisposing the patients to altered nutrient absorption that impacts phosphocalcium metabolism. This study aimed to clarify the prevalence of secondary hyperparathyroidism (SHPT) and its predictors in patients submitted to BS.

METHODS

Retrospective study of 1431 patients who underwent metabolic surgery between January 2010 and June 2017 and who were followed for at least 1 year. We compared the clinical and biochemical characteristics of patients with and without secondary hyperparathyroidism (considering SHPT a PTH ˃ 69 pg/mL). Two different analyses were performed: (1) paired analysis of participants before and 1 year after surgery (N = 441); (2) Cross sectional analysis of participants submitted to bariatric surgery before (N = 441), 1 year after (N = 1431) and 4 years after surgery (N = 333). Multiple logistic regression models were used to evaluate possible predictors of SHPT after BS.

RESULTS

The overall prevalence of SHPT was 24.9% before surgery, 11.2% 1 year after surgery and 21.3% 4 years after surgery. Patients submitted to LAGB had the highest prevalence of SHPT 1 year after surgery (19.4%; vs RYGB, 12.8%, vs SG, 5.3%). Four years after surgery, RYGB had the highest prevalence of SHPT (27.0%), followed by LAGB (13.2%) and SG (6.9%). Higher body mass index and age, decreased levels of vitamin D and RYGB seem to be independent predictors of SHPT 1 year after surgery. The only independent predictor of SHPT 4 years after surgery was RYGB.

CONCLUSION

The prevalence of SHPT is higher before and 4 years after BS than 1 year after surgery. This fact raises some questions about the efficacy of the implemented follow-up plans of vitamin D supplementation on the long term, mainly among patients submitted to RYGB.

Adequate vitamin D supplementation does not ameliorate bone loss following long limb-biliopancreatic diversion in morbidly obese women

OBJECTIVES

The objective of this study is to investigate the effect of adequate vitamin D supplementation on bone mineral density (BMD) following long limb-biliopancreatic diversion (LL-BPD), a malabsorptive bariatric operation.

BACKGROUND

Marked weight loss following bariatric surgery is associated with significant decrease in BMD, attributed to the weight loss and to nutritional, mineral, and vitamin D deficiencies resulting in secondary hyperparathyroidism.

METHODS

Two groups, of 35 and 37 healthy, obese (BMI, 50.4 + 6.6 and 46.5 + 4.8 g/cm²), premenopausal, normally menstruating women underwent LL-BPD. Both groups received high-calcium diets, 600 IU of vitamin D, and 1000 mg elemental calcium daily, while group B received an extra dose of vitamin D (10,000 IU/day) during the first postoperative month, followed by dose adjustment in order to maintain 25OHD concentration higher than 30 μg/L. Areal BMD (aBMD) was measured at the lumbar spine preoperatively and 1 year postoperatively.

RESULTS

One year postoperatively, BMI decreased by approximately 19 kg/m² in both groups, while 25-OH-vitamin D levels did not change in group A (18.7 + 9.1 to 20.2 + 13.0 μg/L, (p = 0.57)) and increased in group B (15.58 ± 5.73 to 52.97 ± 15.46 μg/L, (p = < 0.001). PTH levels increased in group A (from 38.5 ± 12.2 to 51.2 ± 32.8 pg/ml) (p = 0.047) and decreased in group B (from 51.61 ± 18.7 to 45.1 ± 17.8 pg/ml) (p = 0.042). Lumbar spine aBMD decreased similarly in both groups (p = 0.311, for the comparison between groups) from 1.198 + 0.14 to 1.103 + 0.15 g/cm² in group A (p < 0.001) and from 1.157 + 0.14 to 1.076 + 0.14 g/cm² in group B (p < 0.001) and Z-score from 0.93 + 0.97 to 0.19 + 1.02, (p < 0.001) and from 1.15 + 1.29 to 0.419 + 1.28, (p < 0.001), respectively.

CONCLUSIONS

LL-BPD leads to similar and significant bone mass reduction 1 year postoperatively, irrespective of adequate vitamin D replacement and in the absence of secondary hyperparathyroidism.

Intestinal Calcium Absorption

In this article, we focus on mammalian calcium absorption across the intestinal epithelium in normal physiology. Intestinal calcium transport is essential for supplying calcium for metabolism and bone mineralization. Dietary calcium is transported across the mucosal epithelia via saturable transcellular and nonsaturable paracellular pathways, both of which are under the regulation of 1,25-dihydroxyvitamin D₃ and several other endocrine and paracrine factors, such as parathyroid hormone, prolactin, 17β-estradiol, calcitonin, and fibroblast growth factor-23. Calcium absorption occurs in several segments of the small and large intestine with varying rates and capacities. Segmental heterogeneity also includes differential expression of calcium transporters/carriers (e.g., transient receptor potential cation channel and calbindin-D_9k ) and the presence of favorable factors (e.g., pH, luminal contents, and gut motility). Other proteins and transporters (e.g., plasma membrane vitamin D receptor and voltage-dependent calcium channels), as well as vesicular calcium transport that probably contributes to intestinal calcium absorption, are also discussed. © 2021 American Physiological Society. Compr Physiol 11:1-27, 2021.

Comprehensive Analysis of the Components of Walnut Kernel (Juglans regia L.) in China

The contents of main components in 45 walnut kernels from 5 walnut-planting provinces in China (Yunnan, Shaanxi, Shandong, Hebei, and Sichuan) were determined using colorimetry, high-performance liquid chromatography, and gas chromatography, including flavonoids, vitamin E, trace elements, fatty acids, and amino acids. The levels of flavonoids and vitamin E were higher in walnuts from Yunnan than in walnuts from the other four provinces. The levels of zinc and iron were relatively higher in walnuts from Shandong, and the calcium content in walnuts from Yunnan was much lower. No obvious difference was found in crude fat concentration for nuts from the five provinces, but differences were observed in the crude protein content. Oleic acid was the predominant unsaturated fatty acids in all walnut species; the monounsaturated fatty acid content was the highest in walnuts from Yunnan. The data obtained here provided insight into differences in walnuts resulting from different growing environments and germplasm genetic traits.

Impact of Metabolic Surgery on Type-2 Diabetes Remission

Diabetes Mellitus is characterized by numerous metabolic disorders, which have in common the serum elevation of glucose, caused for a pancreatic malfunction in insulin secretion and / or its action. It is a non-communicable disease, considered major public health problems and generalized growth worldwide, being a chronic disease, which can generate a high treatment cost. Metabolic surgery is a safe treatment, regulated by the Federal Council of Medicine and useful in treating people with BMI over 30 years of age, who are unable to control pathologies associated with obesity, primarily type 2 diabetes. The general objective of this study is to understand through a literature review the main impacts of metabolic surgery about the remission of DM 2. This present study it is an exploratory and descriptive study carried out through a literature review. Data were collected through research in virtual health databases, at the Virtual Health Library - VHL, Latin American and Caribbean Health Sciences Information System, LILACS, National Library of Medicine - MEDLINE, Scielo, USP database, PUBMED theses and books. Metabolic surgery proof be a good and effective treatment for having and maintaining good weight loss, as well as a significant clinical and metabolic improvement that extends beyond weight loss. Metabolic surgery is a satisfactory way of achieving long-term weight reduction in obese individuals, increasing survival for these patients. Obese patients with DM2 have a long-term remission of DM2 after bariatric / metabolic surgery. Therefore, it concludes that such procedure is effective in the treatment of the disease and other diseases associated with obesity.

Barocrinology: The Endocrinology of Obesity from Bench to Bedside

Obesity has reached pandemic proportions. Hormonal and metabolic imbalances are the key factors that lead to obesity. South Asian populations have a unique phenotype, peculiar dietary practices, and a high prevalence of consanguinity. Moreover, many lower middle-income countries lack appropriate resources, super-specialists, and affordability to manage this complex disorder. Of late, there has been a substantial increase in both obesity and diabesity in India. Thus, many more patients are being managed by different types of bariatric procedures today than ever before. These patients have many types of endocrine and metabolic disturbances before and after bariatric surgery. Therefore, these patients should be managed by experts who have knowledge of both bariatric surgery and endocrinology. The authors propose “Barocrinology”, a novel terminology in medical literature, to comprehensively describe the field of obesity medicine highlighting the role of knowing endocrine physiology for understating its evolution, insights into its complications and appreciating the changes in the hormonal milieu following weight loss therapies including bariatric surgery. Barocrinology, coined as a portmanteau of “baro” (weight) and endocrinology, focuses upon the endocrine and metabolic domains of weight physiology and pathology. This review summarizes the key pointers of bariatric management from an endocrine perspective.

The effects of adolescent laparoscopic adjustable gastric band and sleeve gastrectomy on markers of bone health and bone turnover

25-hydroxy vitamin D (25 OHD) deficiency and secondary hyperparathyroidism have been seen after metabolic and bariatric surgery, but data are lacking on the bone health outcomes of adolescent sleeve gastrectomy (SG). The purpose of this study was to examine bone-related nutrition after SG, compared to laparoscopic adjustable gastric band (LAGB), and trend bone turnover markers following SG. This is an observational study of 197 adolescents who underwent LAGB (n = 98) or SG (n = 99). Bone health labs were collected at baseline and 6 and/or 12 months after LAGB or SG, with additional analysis of bone turnover markers in the SG group. Calcium and 25 OHD levels increased at 6 and 12 months after LAGB and SG, with no difference between the surgeries. Parathyroid hormone levels decreased only in the SG group. SG patients had increased osteocalcin and carboxy-terminal cross-linking telopeptide of type 1 collagen (CTX) at 6 and 12 months post-SG, although CTX decreased between 6 and 12 months. Excess weight loss at 6 months predicted the rise in CTX, but the changes in osteocalcin and CTX could not be attributed to 25 OHD deficiency, hypocalcemia or hyperparathyroidism. Patients had improved 25 OHD levels post-surgery, which may be secondary to stringent vitamin supplementation guidelines. However, there were marked increases in bone turnover markers following SG. More studies are needed to evaluate the effects of SG on adolescent bone health and to correlate the early changes in bone turnover with bone mineral density and fracture risk.

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.

Reversal of Roux-en-Y Gastric Bypass Fails to Facilitate the Management of Recalcitrant Hypocalcaemia Caused by Primary Hypoparathyroidism

Roux-en-Y gastric bypass (RYGB) is thought to reduce calcium absorption from the gut. Here, we report the case of a patient with a RYGB, who developed primary hypoparathyroidism after a total thyroidectomy, leading to recalcitrant hypocalcaemia. Despite aggressive oral calcium and calcitriol supplementation, she remained hypocalcaemic and required intravenous (IV) calcium supplementation to control her symptoms, and to keep calcium serum levels within an acceptable range. Teriparatide treatment improved calcium levels marginally. This treatment, however, was poorly tolerated and ultimately stopped by the patient. As a last resort, reversal of RYGB was performed to improve calcium absorption from the gut. Unfortunately, IV calcium supplementation remained necessary. This case illustrates that the reversal of RYGB is not always a guarantee for success in managing recalcitrant hypocalcaemia.

Bariatric Surgery: Remission of Inflammation, Cardiometabolic Benefits, and Common Adverse Effects

Obesity is associated with increased mortality as a result of several comorbidities which occur in tandem with the obese state. Chronic inflammation is well documented in obesity, and evidence from numerous studies support the notion that the increased inflammation in individuals with obesity accentuates the comorbidities seen in this condition. The remission of comorbidities such as metabolic, cardiovascular, and neurological complications occurs following bariatric procedures. Bariatric surgery significantly reduces mortality and results in remarkable weight loss and reversal in several obesity-related comorbidities. There is indisputable evidence that the resolution of inflammation that occurs after bariatric surgery mitigates some of these comorbidities. With the increasing use of bariatric surgery for the treatment of severe obesity, it is pivotal to elucidate the underlying mechanisms responsible for the notable improvements seen after the procedure. This review summarizes underlying mechanisms responsible for the remission of obesity-related abnormalities and discusses the common adverse effects of bariatric surgery. Well-stratified, large-scale studies are still needed for a proper evaluation of these underlying mechanisms.

Nutritional Counseling Program for Morbidly Obese Patients Enables Weight Optimization for Safe Total Joint Arthroplasty

Obesity affects one-third of total joint arthroplasty (TJA) patients and is the most common modifiable risk factor for increased complications in the TJA population. The authors' institution implemented a body mass index (BMI) cutoff of 40 kg/m² to define appropriate TJA candidates. Patients above the cutoff were referred for nutritional counseling. The study objective was to evaluate the efficacy of this protocol in optimizing patient BMI for safe and successful TJA. Between 2016 and 2018, the authors examined 133 patients (mean age, 62.6 years) with a BMI greater than 40 kg/m² seeking TJA (94 knee, 39 hip) seen by an arthroplasty surgeon and then a dietitian. Outcomes included weight loss, change in BMI, duration of counseling, and surgical status. For postoperative patients, 90-day complications were recorded. A total of 102 (92%) patients achieved weight loss during a mean 154 days (range, 8-601 days). Patients lost a mean of 17 lb, lowering their BMI by 2.7 points (range, +6.3 to -17.7 points). Twenty-two patients discontinued nutritional counseling after 1 visit, most commonly secondary to cost when not covered by insurance. Seventy-one patients successfully underwent TJA, representing 64% of those patients who participated in nutritional counseling. Complications included delayed wound healing (n=2), periprosthetic fracture (n=2), infection (n=1), cellulitis (n=1), and peroneal nerve palsy (n=1). Surgeons must actively counsel obese patients about weight optimization as part of the preoperative standard of care. Nutritional counseling with a dietitian and follow-up with the surgeon translated to safe and successful TJA in a majority of patients. [Orthopedics. 2020;43(4):e316-e322.].

Intestinal Ca2+ absorption revisited: A molecular and clinical approach

Ca2+ has an important role in the maintenance of the skeleton and is involved in the main physiological processes. Its homeostasis is controlled by the intestine, kidney, bone and parathyroid glands. The intestinal Ca2+ absorption occurs mainly via the paracellular and the transcellular pathways. The proteins involved in both ways are regulated by calcitriol and other hormones as well as dietary factors. Fibroblast growth factor 23 (FGF-23) is a strong antagonist of vitamin D action. Part of the intestinal Ca2+ movement seems to be vitamin D independent. Intestinal Ca2+ absorption changes according to different physiological conditions. It is promoted under high Ca2+ demands such as growth, pregnancy, lactation, dietary Ca2+ deficiency and high physical activity. In contrast, the intestinal Ca2+ transport decreases with aging. Oxidative stress inhibits the intestinal Ca2+ absorption whereas the antioxidants counteract the effects of prooxidants leading to the normalization of this physiological process. Several pathologies such as celiac disease, inflammatory bowel diseases, Turner syndrome and others occur with inhibition of intestinal Ca2+ absorption, some hypercalciurias show Ca2+ hyperabsorption, most of these alterations are related to the vitamin D endocrine system. Further research work should be accomplished in order not only to know more molecular details but also to detect possible therapeutic targets to ameliorate or avoid the consequences of altered intestinal Ca2+ absorption.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Bariatric Surgery in Obesity: Effects on Gut Microbiota and Micronutrient Status

Obesity is associated with reduced gut microbial diversity and a high rate of micronutrient deficiency. Bariatric surgery, the therapy of choice for severe obesity, produces sustained weight loss and improvements in obesity-related comorbidities. Also, it significantly alters the gut microbiota (GM) composition and function, which might have an important impact on the micronutrient status as GM is able to synthesize certain vitamins, such as riboflavin, folate, B12, or vitamin K2. However, recent data have reported that GM is not fully restored after bariatric surgery; therefore, manipulation of GM through probiotics represents a promising therapeutic approach in bariatric patients. In this review, we discuss the latest evidence concerning the relationship between obesity, GM and micronutrients, the impact of bariatric surgery on GM in relation with micronutrients equilibrium, and the importance of the probiotics' supplementation in obese patients submitted to surgical treatment.

Increased risk of osteoporotic fracture in community-dwelling elderly men 20 or more years after gastrectomy: The Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) Cohort Study

PURPOSE

Many studies have reported that patients with a history of gastrectomy (gastrectomized patients) have lower areal bone mineral density (aBMD) and higher fracture risk than those without. However, population-based studies on this topic are scarce, and little is known regarding the bone metabolic status of gastrectomized patients in the long-term. This study aimed to clarify the association of gastrectomy with aBMD, bone metabolism markers, and fracture risk in community-dwelling elderly Japanese men.

METHODS

A total of 1992 men aged ≥65 years completed baseline measurements including aBMD at the spine and hip, serum levels of intact parathyroid hormone (PTH), intact osteocalcin (OC), tartrate-resistant acid phosphatase isoenzyme 5b (TRACP5b), and undercarboxylated OC (ucOC), and an interview regarding past medical history including gastrectomy. Osteoporotic fractures (OPFs) that occurred during the 5-year follow-up period were determined through structured interviews.

RESULTS

After excluding participants with type 1 diabetes mellitus and those with missing values, 1985 men, including 132 gastrectomized men, were analyzed. Gastrectomized men had significantly higher PTH, TRACP5b, and ucOC levels, and lower aBMD, than non-gastrectomized men. Gastrectomy was associated with a significantly higher risk of OPF after adjusting for confounding variables (hazard ratio (HR): 2.55, 95% confidence interval (CI): 1.17, 5.55), and the risk was no longer significant when further adjusted for PTH and aBMD. Even in this model, however, increase in OPF risk was significant in gastrectomized men who survived 20 years or more after the surgery (HR: 3.56, 95% CI: 1.33, 9.52).

CONCLUSIONS

History of gastrectomy was associated with elevated bone resorption, decreased aBMD, and increased fracture risk in community-dwelling elderly Japanese men. This increase in fracture risk was more prominent long after gastrectomy.

Calcium citrate: from biochemistry and physiology to clinical applications

Adequate daily calcium intake should normally be achieved by dietary sources. Since low calcium diets are quite common in subjects that do not reach the recommended intake and particularly those at risk of fractures, calcium supplements may become necessary. Different forms of calcium salts are available, but products containing calcium citrate and calcium carbonate complexes are the most frequently used. Although only limited evidence on the efficacy and long-term safety of calcium citrate is available, these supplements may represent a valuable product for the management of different chronic pathological conditions. The aim of this review was to evaluate the current and potential clinical applications of calcium citrate. In particular, we focused on the use of calcium citrate supplementation in subjects with osteoporosis or in bariatric patients. Other pathological conditions that could benefit calcium citrate supplementation may include achloridria, chronic hypoparathyroidism and hypocitraturic subjects with moderate/high risk of nephrolithiasis. Indeed, citrate salts are widely used in the treatment of nephrolithiasis, since they have shown an inhibitory effect on kidney stone formation and recurrence.

Metabolic and Endocrine Consequences of Bariatric Surgery

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