Dissociation of body mass index, excess weight loss and body fat percentage trajectories after 3 years of gastric bypass: relationship with metabolic outcomes

Cardiometabolic risk stratification using a novel obesity phenotyping system based on body adiposity and waist circumference

BACKGROUND

The estimation of obesity-associated cardiometabolic risk does not usually take into account body composition or the distribution of adiposity. The aim of the present study was to assess the clinical usefulness of a novel obesity phenotyping system based on the combination of actual body fat percentage (BF%) and waist circumference (WC) according to the cardiometabolic risk estimation.

METHODS

A classification matrix combining BF% and WC as measures of both amount and distribution of adiposity establishing nine body phenotypes (3 BF% x 3 WC) was developed. Individuals were grouped in five different cardiometabolic risk phenotypes. We conducted a validation study in a large cohort of White subjects from both genders representing a wide range of ages and adiposity (n = 12,754; 65 % females, aged 18-88 years).

RESULTS

The five risk groups using the matrix combination of BF% and WC exhibited a robust linear distribution regarding cardiometabolic risk, estimated by the Metabolic Syndrome Severity Score, showing a continuous increase between groups with significant differences (P < 0.001) among them, as well as in other cardiometabolic risk factors. An additional 24 % of patients at very high risk was detected with the new classification system proposed (P < 0.001) as compared to an equivalent matrix using BMI and WC instead of BF% and WC.

CONCLUSIONS

A more detailed phenotyping should be a priority in the diagnosis and management of patients with obesity. Our classification system allows to gradually estimate the cardiometabolic risk according to BF% and WC, thus representing a novel and useful tool for both research and clinical practice.

A multifaceted and inclusive methodology for the detection of sarcopenia in patients undergoing bariatric surgery: an in-depth analysis of current evidence

Bariatric surgery is widely recognized as the most effective intervention for obesity and offers benefits beyond weight loss. However, not all patients achieve satisfactory weight loss, balanced changes in body composition, and resolution of comorbidities. Therefore, thorough pre- and postoperative evaluations are important to predict success and minimize adverse effects. More comprehensive assessments require broadening the focus beyond body weight and fat measurements to consider quantitative and qualitative evaluations of muscles. Introducing the concept of sarcopenia is useful for assessing the degradative and pathological changes in muscles associated with cardiometabolic function, physical performance, and other obesity-related comorbidities in patients undergoing bariatric surgery. However, there is currently no consensus or definition regarding the research and clinical use of sarcopenia in patients undergoing bariatric surgery. Therefore, this review aimed to define the concept of sarcopenia applicable to patients undergoing bariatric surgery, based on the consensus reached for sarcopenia in the general population. We also discuss the methods and significance of measuring muscle mass, quality, and strength, which are key variables requiring a comprehensive assessment.

Precision nutrition in the context of bariatric surgery

Bariatric surgery (BS) is the most effective long-term treatment for severe obesity. This review summarizes the main nutritional deficiencies before and after BS, as well as current dietary and supplementation recommendations to avoid them. Likewise, we have reviewed all those aspects that in recent years have been shown to be related to postoperative weight loss (WL) and its subsequent maintenance, such as hormonal changes, dietary patterns, changes in food preference, adherence to recommendations and follow-up, genetic factors and microbiota, among others. Despite all the knowledge, nutritional deficiencies and weight regain after BS are frequent. It is essential to continue studying in this field in order to establish more precise recommendations according to the individual characteristics of patients. It is also a major objective to understand more deeply the role of the factors involved in WL and its maintenance. This will allow the development of precision treatments and nutrition for patients with obesity, optimizing their benefit after BS.

Relevance of body composition in phenotyping the obesities

Obesity is the most extended metabolic alteration worldwide increasing the risk for the development of cardiometabolic alterations such as type 2 diabetes, hypertension, and dyslipidemia. Body mass index (BMI) remains the most frequently used tool for classifying patients with obesity, but it does not accurately reflect body adiposity. In this document we review classical and new classification systems for phenotyping the obesities. Greater accuracy of and accessibility to body composition techniques at the same time as increased knowledge and use of cardiometabolic risk factors is leading to a more refined phenotyping of patients with obesity. It is time to incorporate these advances into routine clinical practice to better diagnose overweight and obesity, and to optimize the treatment of patients living with obesity.

Effects of preoperative sarcopenia-related parameters on the musculoskeletal and metabolic outcomes after bariatric surgery: a one-year longitudinal study in females

Reduced muscle mass and/or strength are risk factors for metabolic and musculoskeletal impairment. The present study evaluated anthropometric, metabolic, and musculoskeletal outcomes in females with and without sarcopenic-obesity parameters who underwent bariatric surgery during a 1-year follow-up. A prospective, single-center cohort study was conducted in females with obesity undergoing preoperative evaluation for surgery. In the preoperative period, females were allocated into obesity with sarcopenic-obesity parameters (SOP group, n = 15) and without sarcopenic-obesity parameters (obesity group, n = 21). Sarcopenic obesity parameters were defined as lower appendicular skeletal mass adjusted for weight (ASM/wt) and/or low handgrip strength (HGS). Anthropometric, metabolic, and musculoskeletal parameters were assessed before surgery and at 3 months, 6 months, and a 1-year after bariatric surgery. Weight loss was similar between groups (p > 0.05). Weight, body mass index, fat mass, body fat percentage, skeletal muscle mass, fat-free mass, fat-free mass index, HGS were reduced in both groups during the 1-year follow-up (p < 0.05). However, when muscle mass and strength were analyzed relative to body size, an improvement after bariatric surgery was found in both groups (p < 0.05). Total cholesterol, LDL-c, triglycerides, fasting glucose, glycated hemoglobin, insulin, and insulin resistance were reduced in both groups during the 1-year follow-up (p < 0.05). In addition, HDL-c serum concentration increased in females with and without sarcopenic-obesity parameters over the 1-year follow-up (p < 0.05). Both groups had decreased bone mineral density (BMD) at all sites (lumbar spine, femoral neck, and total femur) over the 1-year follow-up (p < 0.05). The highest quartile of ASM/wt was positively associated with BMD variables in a longitudinal analysis, suggesting that preserved ASM/wt in pre-surgery may be beneficial for BMD after 1 year of bariatric surgery. The results showed that bariatric surgery promotes similar musculoskeletal and metabolic changes in females with preserved muscle mass and strength or in females with sarcopenia-related parameters.

Changes in Lean Tissue Mass, Fat Mass, Biological Parameters and Resting Energy Expenditure over 24 Months Following Sleeve Gastrectomy

Sleeve gastrectomy (SG) induces weight loss but its effects on body composition (BC) are less well known. The aims of this longitudinal study were to analyse the BC changes from the acute phase up to weight stabilization following SG. Variations in the biological parameters related to glucose, lipids, inflammation, and resting energy expenditure (REE) were concomitantly analysed. Fat mass (FM), lean tissue mass (LTM), and visceral adipose tissue (VAT) were determined by dual-energy X-ray absorptiometry in 83 obese patients (75.9% women) before SG and 1, 12 and 24 months later. After 1 month, LTM and FM losses were comparable, whereas at 12 months the loss of FM exceeded that of LTM. Over this period, VAT also decreased significantly, biological parameters became normalized, and REE was reduced. For most of the BC, biological and metabolic parameters, no substantial variation was demonstrated beyond 12 months. In summary, SG induced a modification in BC changes during the first 12 months following SG. Although the significant LTM loss was not associated with an increase in sarcopenia prevalence, the preservation of LTM might have limited the reduction in REE, which is a longer-term weight-regain criterion.

Usual dietary intake, physical activity, weight loss, and body composition after five years of Roux-en-Y gastric bypass

OBJECTIVE

To estimate usual dietary intake (UDI), physical activity (PA), and their association with weight loss and body composition in patients who underwent Roux-en-Y gastric bypass (RYGB) after five years in the Federal District, Brazil.

METHODS

We assessed anthropometry and body composition using bioimpedance, and dietary intake and PA with three nonconsecutive 24-h recalls. PC-Side was used to estimate UDI. Dietary patterns (DPs) were identified through principal component analysis, and association between UDI and PA with percentage of total weight loss (%TWL) and fat-free mass (FFM) through multinomial logistic regression.

RESULTS

Sample (n = 124) presented mean (SD) age of 48.9 (9.4) years, median (IQR) of 9 years (7-10) post RYGB, current BMI = 32.3 kg/m² (28.8-35.7), %TWL = 24.7% (10.9), and FFM = 45.1 kg (41.1-51.9). Mean usual energy intake of 1556 kcal/d, with adequate protein intake, poor fiber intake, and excessive carbohydrate, total fat, and added sugar intake, compared to dietary guidelines. Calcium, vitamins C, D, and E presented the greatest inadequacy (15%, 24%, 32%, and 49% of individuals, respectively, reported usual intake below EAR); 83 participants were considered active/very active, according PA. DP with high energy, protein, total fat, saturated fat, and sodium intake, was negatively associated with %TWL (OR = 0.545, p = 0.037). Protein intake was positively associated with FFM (OR = 1.091, p = 0.004). PA was not associated with %TWL or FFM.

CONCLUSION

Participants demonstrated intake of carbohydrate, fat, fiber, added sugar not in accordance with guidelines. A DP rich in energy, protein, total fat, saturated fat, and sodium appears to decrease TWL. However, protein intake appears to increase FFM.

Effect of Weight Regain on Body Composition and Metabolic Biomarkers After Sleeve Gastrectomy: a Cross-Sectional Study from a Hospital Database

INTRODUCTION

Weight regain (WR) is described in approximately 30% of patient's post-bariatric surgery. It is related to the progression or recurrence of associated medical problems and decline in health-related quality of life. This study aimed to test the return of body composition and metabolic biomarkers to pre-operative levels when WR occurs.

METHODS

In this cross-sectional study conducted in 2021, patients were randomly selected from the hospital's electronic databases between 2001 and 2020. Patient demographic data, comorbidities, body compositions, and metabolic biomarkers were collected. Three groups were defined: groups A (WR), B (weight loss), and C (control group; patients with obesity who had not yet undergone bariatric surgery).

RESULTS

A total of 88 patients were enrolled in this study and matched with the control group. The body mass index in group A was 43.8 ± 6.9 kg/m²; group B was 28.6 ± 4.2; group C was 43.9 ± 7.1. Body muscle mass, body fat mass, and visceral fat significantly differed between groups A and B (p < 0.001) but not between groups A and C (p = 0.8). There was a significant difference in leptin, ghrelin, postprandial glucagon-like peptide-1, insulin, and fibroblast growth factor-21 (but not retinol-binding protein-4) between groups A and B. Most metabolic biomarkers in group A returned to the pre-operative values as in group C.

CONCLUSION

WR had a direct negative effect on body composition and metabolic biomarkers, whereby the values returned to pre-operative levels. Early detection of WR and possible additional therapy are necessary to prevent associated medical problems.

Musculoskeletal effects of obesity and bariatric surgery – a narrative review

Obesity affects several areas of the human body, leading to increased morbidity and mortality and the likelihood of other diseases, such as type 2 diabetes mellitus, cardiovascular diseases and musculoskeletal disorders. These conditions predispose to bone fractures and sarcopenic obesity, defined by the presence of an obesity-associated decrease in muscle mass and strength. Both bone fragility and sarcopenic obesity disease are consequences of several factors, such as a low degree of chronic inflammation, insulin resistance, hormonal changes, nutritional deficiencies, ectopic fat deposits and sedentary lifestyle. The diagnosis of obesity-related musculoskeletal disorders is limited by the lack of sarcopenia criteria and lower accuracy of bone mineral density measurement by dual-energy X-ray absorptiometry in overweight people. Reducing body weight provides undeniable benefits to this population, however treating cases of severe obesity with bariatric surgery can cause even greater damage to bone and muscle health, especially in the long term. The mechanisms involved in this process are not yet fully understood, but factors related to nutrient malabsorption and mechanical discharge as well as changes in gut hormones, adipokines and bone marrow adiposity should be taken into account. Depending on the surgical technique performed, greater musculoskeletal damage may occur, especially in cases of malabsorptive surgeries such as Roux-en-Y gastric bypass, when compared to restrictive techniques such as sleeve gastrectomy. This difference is probably due to greater weight loss, nutrient malabsorption and important hormonal changes that occur as a consequence of the diversion of intestinal transit and loss of greater absorptive surface. Thus, people undergoing bariatric procedures, especially malabsorptive ones, should have their musculoskeletal health supervised to allow early diagnosis and appropriate therapeutic interventions to prevent osteoporotic fractures and preserve the functionality of the skeletal muscles.

Body Composition Differences Between Excess Weight Loss ≥ 50% and < 50% at 12 Months Following Bariatric Surgery

Background

The relationship between weight loss and body composition is undefined after bariatric surgery. The objective of this study was to compare body composition changes in patients with excess weight loss ≥ 50% (EWL ≥ 50) and < 50% at 12 months post-operatively (EWL < 50).

Methods

A prospective cohort study was completed on patients undergoing bariatric surgery at two tertiary hospitals between 2017 and 2021. Body composition was measured with dual-energy X-ray absorptiometry immediately before surgery, and at 1, 6, and 12 months post-operatively. Body mass index (BMI), fat mass (FM), lean body mass (LBM), and skeletal muscle index (SMI) trajectories were analysed between patients with EWL ≥ 50% and EWL < 50%.

Results

Thirty-seven patients were included in this series (EWL ≥ 50% n = 25, EWL < 50% n = 12), comprising of both primary and revisional bariatric surgery cases, undergoing a sleeve gastrectomy (62.2%), Roux-en-Y gastric bypass (32.4%), or one anastomosis gastric bypass (5.4%). The EWL ≥ 50% group demonstrated a more optimal mean FM-to-LBM loss ratio than the EWL < 50% group. EWL ≥ 50% patients lost 2.0 kg more FM than EWL < 50% patients for each 1 kg of LBM lost. EWL ≥ 50% was also associated with an increase in mean SMI% over 12 months (5.5 vs. 2.4%; p < 0.0009). Across the whole cohort, the first month after surgery accounted for 67.4% of the total LBM reduction that occurred during the 12-month post-operative period.

Conclusion

This data suggests EWL ≥ 50% is associated with a more optimal body composition outcome than EWL < 50%. LBM reduction occurs predominantly in the early post-operative period.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s11695-022-06128-3.

Why does obesity cause diabetes?

The accumulation of an excessive amount of body fat can cause type 2 diabetes, and the risk of type 2 diabetes increases linearly with an increase in body mass index. Accordingly, the worldwide increase in the prevalence of obesity has led to a concomitant increase in the prevalence of type 2 diabetes. The cellular and physiological mechanisms responsible for the link between obesity and type 2 diabetes are complex and involve adiposity-induced alterations in β cell function, adipose tissue biology, and multi-organ insulin resistance, which are often ameliorated and can even be normalized with adequate weight loss.

Trajectory Analysis and Predictors of the Percentage of Body Fat Among Chinese Sleeve Gastrectomy Patients

BACKGROUND

The weight loss in Chinese patients after sleeve gastrectomy is different, and the differences can be evaluated through the trajectories of the percentage of body fat (BF%). Patients' baseline psychosocial factors may be associated with these trajectories.

MATERIALS AND METHODS

We selected 267 patients who received sleeve gastrectomy for the first time. The BF% at baseline and 1, 3, 6, 12 months after surgery and baseline psychosocial variables were retrospectively collected. The trajectory model was established according to BF% based on the growth mixture model. The baseline psychosocial variables were compared among different trajectory classes.

RESULTS

Four types of trajectory classes were obtained. The differences in preoperative dietary self-efficacy, exercise self-efficacy, depression, social support, working status, alcohol consumption, and gender among the classes were statistically significant. The pairwise comparison of the above variables revealed that the differences of gender, dietary self-efficacy and exercise self-efficacy among classes were highly effective.

CONCLUSION

Female gender, low dietary self-efficacy and low exercise self-efficacy were predictors for poor BF% trajectory in sleeve gastrectomy patients. Health professionals can early identify patients who are most likely to lose weight in a not-ideal manner based on the above predictors.

Impact of Bariatric Surgery on Adipose Tissue Biology

Bariatric surgery (BS) procedures are actually the most effective intervention to help subjects with severe obesity achieve significant and sustained weight loss. White adipose tissue (WAT) is increasingly recognized as the largest endocrine organ. Unhealthy WAT expansion through adipocyte hypertrophy has pleiotropic effects on adipocyte function and promotes obesity-associated metabolic complications. WAT dysfunction in obesity encompasses an altered adipokine secretome, unresolved inflammation, dysregulated autophagy, inappropriate extracellular matrix remodeling and insufficient angiogenic potential. In the last 10 years, accumulating evidence suggests that BS can improve the WAT function beyond reducing the fat depot sizes. The causal relationships between improved WAT function and the health benefits of BS merits further investigation. This review summarizes the current knowledge on the short-, medium- and long-term outcomes of BS on the WAT composition and function.

Body Composition, Basal Metabolic Rate and Leptin in Long-Term Weight Regain After Roux-en-Y Gastric Bypass Are Similar to Pre-surgical Obesity

PURPOSE

The purpose of this study is to evaluate the relationship between body composition, basal metabolic rate (BMR), and serum concentrations of leptin with long-term weight regain after Roux-en-Y gastric bypass (RYGB) and compare it with obesity before surgery.

MATERIALS AND METHODS

Prospective longitudinal analytical study. Three groups were formed: individuals 60 months post RYGB, with weight regain (G1) and without it (G2), and individuals with obesity who had not undergone bariatric surgery (G3). Body fat (BF), body fat mass (BFM), visceral fat (VF), fat-free mass (FFM), skeletal muscle mass (SMM), and BMR were assessed by octapolar and multi-frequency electrical bioimpedance. Fasting serum concentrations of leptin were measured.

RESULTS

Seventy-two individuals were included, 24 in each group. Higher means of BF, BFM, VF, and leptin levels were observed in G1, when compared to G2 (BF: 47.5 ± 5.6 vs. 32.0 ± 8.0, p < 0.05; FBM: 47.8 ± 11.6 vs. 23.9 ± 7.0, p < 0.05; VF: 156.8 ± 30.2 vs. 96.1 ± 23.8, p < 0.05; leptin: 45,251.2 pg/mL ± 20,071.8 vs. 11,525.7 pg/mL ± 9177.5, p < 0.000). G1 and G2 did not differ in FFM, SMM, and BMR. G1 and G3 were similar according to BF, FFM, BMR, and leptin levels. Body composition, but not leptin, was correlated with %weight regain in G1 (FBM: r = 0.666, p < 0.000; BF: r = 0.428, p = 0.037; VF: r = 0.544, p = 0.006).

CONCLUSION

Long-term weight regain after RYGB is similar to pre-surgical obesity in body composition, BMR, and leptin concentrations, indicating relapse of metabolic and hormonal impairments associated with excessive body fat.

A Comparison of Total Food Intake at a Personalised Buffet in People with Obesity, before and 24 Months after Roux-en-Y-Gastric Bypass Surgery

Long-term reductions in the quantity of food consumed, and a shift in intake away from energy dense foods have both been implicated in the potent bariatric effects of Roux-en-Y gastric bypass (RYGB) surgery. We hypothesised that relative to pre-operative assessment, a stereotypical shift to lower intake would be observed at a personalised ad libitum buffet meal 24 months after RYGB, driven in part by decreased selection of high energy density items. At pre-operative baseline, participants (n = 14) rated their preference for 72 individual food items, each of these mapping to one of six categories encompassing high and low-fat choices in combination with sugar, complex carbohydrate or and protein. An 18-item buffet meal was created for each participant based on expressed preferences. Overall energy intake was reduced on average by 60% at the 24-month buffet meal. Reductions in intake were seen across all six food categories. Decreases in the overall intake of all individual macronutrient groups were marked and were generally proportional to reductions in total caloric intake. Patterns of preference and intake, both at baseline and at follow-up appear more idiosyncratic than has been previously suggested by verbal reporting. The data emphasise the consistency with which reductions in ad libitum food intake occur as a sequel of RYGB, this being maintained in the setting of a self-selected ad libitum buffet meal. Exploratory analysis of the data also supports prior reports of a possible relative increase in the proportional intake of protein after RYGB.

Assessment of body composition in obese patients undergoing one anastomosis gastric bypass: cross-sectional study

Bariatric surgery is the most effective long-term treatment to obesity, and it is necessary to assess changes in body composition and to be able to establish better follow-up of patients. Cross-sectional, observational study in patients undergoing One Anastomosis Gastric Bypass (OAGB) bariatric surgery. We analysed changes in weight and body composition during the first postoperative year. 405 patients (68.9% women. 31.1% men), mean age 44 years, mean weight 110.02 kg, Body Mass Index (BMI) 39.76 kg/m², height 1.66 m. The variables analyzed were substantially decreased compared to the preoperative values one year after surgery in every case: weight (110.02 ± 22.03 kg vs. 69.36 ± 13.60 kg), BMI (39.76 ± 6.65 vs. 24.52 ± 3. 76), fat free mass (61.12 ± 12.43 kg vs. 53.61 ± 11.61 kg), fat mass (50.44 ± 14.36 kg vs. 15.74 ± 6.74 kg), bone mass (58.06 ± 11.85 kg vs. 50.92 ± 11.06 kg) and water (45.08 ± 9.99 kg vs. 37.39 ± 9.23 kg), P < 0.001. The results show noticeable improvements in weight reduction and changes in body composition, and will contribute to develop a thorough understanding of both of them, contributing also to perform a better patients’ follow-up.

Insulin resistance in bariatric surgery

PURPOSE OF REVIEW

To give an updated review on the underlying mechanisms and clinical effects of improved glucose control after bariatric surgery.

RECENT FINDINGS

The basic principles of the mechanism for the metabolic effects of bariatric surgery can be categorized into calorie restriction, deviation of nutrients, and reduced amounts of adipose tissue. Recent findings suggest the importance of early changes following deviation of nutrients to more distal parts of the small bowel resulting in altered release of gastrointestinal hormones, altered gut microbiota, and weight-reduction. In the long-term, loss of adipose tissue results in reduced inflammation and improved insulin sensitivity. From a clinical perspective these changes are associated with remission of diabetes in patients with morbid obesity and type 2 diabetes, prevention of diabetes in patients with insulin resistance without overt type 2 diabetes and prevention of both microvascular and macrovascular complications for all patients with morbid obesity.

SUMMARY

At present, bariatric surgery remains the most effective treatment option to improve glucose control and long-term complications associated with hyperglycemia in patients with obesity.Although the mechanisms behind these metabolic effects remain only partially understood, further knowledge on these complex mechanisms may help identifying durable treatment options for morbid obesity and important metabolic comorbidities.

The brown bear as a translational model for sedentary lifestyle-related diseases

Sedentary lifestyle accelerates biological ageing, is a major risk factor for developing metabolic syndrome and is associated with cardiovascular disease, diabetes mellitus, kidney failure, sarcopenia and osteoporosis. In contrast to the linear path to worsening health in humans with metabolic syndrome, brown bears have developed a circular metabolic plasticity enabling these animals to tolerate obesity and a 'sedentary lifestyle' during hibernation and exit the den metabolically healthy in spring. Bears are close to humans physiology wise, much closer than rodents, the preferred experimental animals in medical research, and may better serve as translational model to develop treatments for lifestyle-related diseases. In this review, aspects of brown bear hibernation survival strategies are outlined and conceivable experimental strategies to learn from bears are described.

Metabolic Impact of Body Fat Percentage Independent of Body Mass Index in Women with Obesity Remission After Gastric Bypass

BACKGROUND/OBJECTIVE

Body mass index (BMI) is central when evaluating treatment effect after gastric bypass. The metabolic impact of BMI-independent differences in body fat percentage (BF%) after gastric bypass is not fully understood. We compared metabolic and adipose tissue characteristics in women with high versus low BF% independent of BMI after obesity remission following gastric bypass.

SUBJECTS/METHODS

A cohort of 215 women was included at baseline. A total of 166 women were re-examined 2 years after gastric bypass, whereof 130 had obesity remission (BMI < 30 kg/m2). Anthropometric parameters, blood pressure, and lipids were measured. Total and regional body fat mass was determined by dual-energy X-ray absorptiometry. Insulin sensitivity was assessed by homeostasis model assessment of insulin resistance (HOMA-IR) and hyperinsulinemic euglycemic clamp (M value). Adipocyte size and number were determined.

RESULTS

Of the 130 women with obesity remission, 64 had BF% ≥ 35 and 65 < 35. Independent of BMI, high BF% were associated with higher HOMA-IR (P = 0.021), lower M value (P = 0.0046), higher triglycerides (P = 0.013), higher visceral/total and android/gynoid fat mass ratios (P = 0.0032 and 0.0003 respectively), and larger subcutaneous fat cell volume (P < 0.0001) 2 years after gastric bypass. No differences in anthropometric measures, glucose, blood pressure, or fat cell number were observed.

CONCLUSIONS

Independent of BMI, patients with higher BF% displayed lower insulin sensitivity, higher triglyceride levels, central fat distribution, and larger subcutaneous adipocytes 2 years after gastric bypass. Thus, determination of BF% provides additional information of metabolic characteristics at follow-up of non-obese patients after gastric bypass.

Bariatric Surgery and Type 1 Diabetes: Unanswered Questions

In recent decades there has been an alarming increase in the prevalence of obesity in patients with type 1 diabetes leading to the development of insulin resistance and cardiometabolic complications, with mechanisms poorly clarified. While bariatric surgery has long been considered an effective treatment option for patients with type 2 diabetes, the evidence regarding its benefits on weight loss and the prevention of complications in T1DM patients is scarce, with controversial outcomes. Bariatric surgery has been associated with a significant reduction in daily insulin requirement, along with a considerable reduction in body mass index, results which were sustained in the long term. Furthermore, studies suggest that bariatric surgery in type 1 diabetes results in the improvement of comorbidities related to obesity including hypertension and dyslipidemia. However, regarding glycemic control, the reduction of mean glycosylated hemoglobin was modest or statistically insignificant in most studies. The reasons for these results are yet to be elucidated; possible explanations include preservation of beta cell mass and increased residual function post-surgery, improvement in insulin action, altered GLP-1 function, timing of surgery, and association with residual islet cell mass. A number of concerns regarding safety issues have arisen due to the reporting of peri-operative and post-operative adverse events. The most significant complications are metabolic and include diabetic ketoacidosis, severe hypoglycemia and glucose fluctuations. Further prospective clinical studies are required to provide evidence for the effect of bariatric surgery on T1DM patients. The results may offer a better knowledge for the selection of people living with diabetes who will benefit more from a metabolic surgery.

A Retrospective Study about the Differences in Cardiometabolic Risk Indicators and Level of Physical Activity in Bariatric Surgery Patients from Private vs. Public Units

Background: Obesity is a pathology with a growing incidence in developing countries. Objective: To evaluate the evolution of cardiometabolic, anthropometrics, and physical activity parameters in individuals undergoing bariatric surgery (BS) in the public healthcare system (PUS) and private healthcare system (PHS). Methods: A longitudinal, observational, and retrospective study was conducted with 111 bariatric patients on two different health systems, with 60 patients from the PUS and 51 from the PHS. Cardiometabolic risk (CR) was analyzed by the assessment of obesity-related comorbidities (AORC) on admission and 3, 6, and 12 months after BS, and the International Physical Activity Questionnaire (IPAQ) was surveyed before and 12 months after BS. In addition, cardiometabolic risk was also assessed by biochemical (fasting glucose and complete lipidogram) and anthropometric (weight, weight loss, waist circumference, and waist-to-height ratio) parameters. Results: On admission, the parameters of severe obesity, systemic arterial hypertension (SAH), Diabetes mellitus (DM), and waiting time to BS were higher in the PUS. Additionally, in the PUS, AORC was reduced only in the SAH parameter. However, in the post-surgery moment, AORC reduced, and there was no difference between the two groups after BS. Regarding physical activity, the IPAQ showed a higher level of activity in the PHS before and one year after BS. Conclusion: At the PUS, BS is performed in patients with a higher degree of comorbidities, but BS improved the reduction of the CR at a similar level to those observed in the PHS.

Prospective Longitudinal Trends in Body Composition and Clinical Outcomes 3 Years Following Sleeve Gastrectomy

BACKGROUND AND AIMS

Longitudinal assessment of body composition following bariatric surgery allows monitoring of health status. Our aim was to elucidate trends of anthropometric and clinical outcomes 3 years following sleeve gastrectomy (SG).

METHODS

A prospective cohort study of 60 patients who underwent SG. Anthropometrics including body composition analysis measured by multi-frequency bioelectrical impedance analysis, blood tests, liver fat content measured by abdominal ultrasound and habitual physical activity were evaluated at baseline and at 6 (M6), 12 (M12), and 36 (M36) months post-surgery.

RESULTS

Sixty patients (55% women, age 44.7 ± 8.7 years) who completed the entire follow-up were included. Fat mass (FM) was reduced significantly 1 year post-surgery (55.8 ± 11.3 to 26.7 ± 8.3 kg; P < 0.001) and then increased between 1 and 3 years post-operatively, but remained below baseline level (26.7 ± 8.3 to 33.1 ± 11.1 kg; P < 0.001). Fat free mass (FFM) decreased significantly during the first 6 months (64.7 ± 14.3 to 56.9 ± 11.8 kg; P < 0.001), slightly decreased between M6 and M12 and then reached a plateau through M36. Weight loss "failure" (< 50% excess weight loss) was noticed in 5.0% and 28.3% of patients at M12 and M36, respectively. Markers of lipid and glucose metabolism changed thereafter in parallel to the changes observed in FM, with the exception of HDL-C, which increased continuingly from M6 throughout the whole period analyzed (45.0 ± 10.2 to 59.5 ± 15.4 mg/dl; P < 0.001) and HbA1c which continued to decrease between M12 and M36 (5.5 ± 0.4 to 5.3 ± 0.4%; P < 0.001). There were marked within-person variations in trends of anthropometric and clinical parameters during the 3-year follow-up.

CONCLUSIONS

Weight regain primarily attributed to FM with no further decrease in FFM occurs between 1 and 3 years post-SG. FM increase at mid-term may underlie the recurrence of metabolic risk factors and can govern clinical interventions.

Relationship Between Skeletal Muscle Mass Indexes and Muscular Function, Metabolic Profile and Bone Mineral Density in Women with Recommendation for Bariatric Surgery

BACKGROUND AND AIM

We evaluated low skeletal muscle mass (LMM) in women prior to bariatric surgery (BS) through different skeletal muscle mass indexes (MMIs) regarding body fat percentage (BFP), handgrip strength (HS), six-minute walk test (6MWT), metabolic profile and bone mineral density (BMD).

METHODS

Women (n=62) were allocated into two groups according to LMM: obesity with low muscle mass (OLMM) or obesity with normal muscle mass (ONMM). LMM was defined by the appendicular skeletal muscle mass (ASM) adjusted for weight (ASM/wt × 100) and ASM adjusted for body mass index (ASM/BMI), considering the lowest quintile of the indexes studied.

RESULTS

OLMM was found in 30.5% by ASM/wt × 100 and 20.3% by ASM/BMI. Using the ASM/wt × 100, OLMM group had a high BFP, low HS and BMD in L1-L4, femoral neck (FN) and total femur (TF) when compared with ONMM (p < 0.05). Using ASM/BMI, OLMM group had increased BFP, reduced HS and 6MWT in comparison to ONMM (p < 0.05). Metabolic profile was similar between OLMM and ONMM groups by the two MMIs. MMIs were negatively correlated with BFP (p < 0.05) and positively correlated with HS (p < 0.05), and none of them with 6MWT (p > 0.05). ASM/wt × 100 was positively correlated with all BMD sites assessed (p < 0.05). There was positive correlation between ASM/wt × 100 and ASM/BMI.

CONCLUSION

OLMM identified by the ASM/wt × 100 and ASM/BMI had higher adiposity and lower HS. Using ASM/BMI, we found that OLMN had a poor physical performance, while the ASM/wt × 100 identified a lower BMD at all sites.

Mechanisms Underlying Type 2 Diabetes Remission After Metabolic Surgery

Type 2 diabetes prevalence is increasing dramatically worldwide. Metabolic surgery is the most effective treatment for selected patients with diabetes and/or obesity. When compared to intensive medical therapy and lifestyle intervention, metabolic surgery has shown superiority in achieving glycemic improvement, reducing number of medications and cardiovascular risk factors, which translates in long-term benefits on cardiovascular morbidity and mortality. The mechanisms underlying diabetes improvement after metabolic surgery have not yet been clearly understood but englobe a complex interaction among improvements in beta cell function and insulin secretion, insulin sensitivity, intestinal gluconeogenesis, changes in glucose utilization, and absorption by the gut and changes in the secretory pattern and morphology of adipose tissue. These are achieved through different mediators which include an enhancement in gut hormones release, especially, glucagon-like peptide 1, changes in bile acids circulation, gut microbiome, and glucose transporters expression. Therefore, this review aims to provide a comprehensive appraisal of what is known so far to better understand the mechanisms through which metabolic surgery improves glycemic control facilitating future research in the field.

Adipokine dysregulation and adipose tissue inflammation in human obesity

Obesity, a worldwide epidemic, confers increased risk for multiple serious conditions, including type 2 diabetes, cardiovascular diseases, nonalcoholic fatty liver disease and cancer. Adipose tissue is considered one of the largest endocrine organs in the body as well as an active tissue for cellular reactions and metabolic homeostasis rather than an inert tissue for energy storage. The functional pleiotropism of adipose tissue relies on its ability to synthesize and release a large number of hormones, cytokines, extracellular matrix proteins and growth and vasoactive factors, collectively termed adipokines that influence a variety of physiological and pathophysiological processes. In the obese state, excessive visceral fat accumulation causes adipose tissue dysfunctionality that strongly contributes to the onset of obesity-related comorbidities. The mechanisms underlying adipose tissue dysfunction include adipocyte hypertrophy and hyperplasia, increased inflammation, impaired extracellular matrix remodelling and fibrosis together with an altered secretion of adipokines. This review describes how adipose tissue becomes inflamed in obesity and summarizes key players and molecular mechanisms involved in adipose inflammation.

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).

The Effect of Obesity on Anti-Xa Concentrations in Bariatric Patients

BACKGROUND

Morbidly obese patients are at increased risk to develop venous thromboembolism (VTE), especially after bariatric surgery. Adequate postoperative thrombosis prophylaxis is of utmost importance. It is assumed that morbidly obese patients need higher doses of low molecular weight heparin (LMWH) compared to normal-weight patients; however, current guidelines based on relative efficacy in obese populations are lacking.

OBJECTIVES

First, we will evaluate the relationship between body weight descriptors and anti-Xa activity prospectively. Second, we will determine the dose-linearity of LMWH in morbidly obese patients.

SETTING

This study was performed in a general hospital specialized in bariatric surgery.

METHODS

Patients were scheduled for a Roux-en-Y gastric bypass with a total bodyweight (TBW) of ≥ 140 kg. Patients (n = 50, 64% female) received a daily postoperative dose of 5700 IU of nadroparin for 4 weeks. Anti-Xa activity was determined 4 h after the last nadroparin administration. To determine the dose linearity, anti-Xa was determined following a preoperative dose of 2850 IU nadroparin in another 50 patients (52%).

RESULTS

TBW of the complete group was 148.5 ± 12.6 kg. Mean anti-Xa activity following 5700 IU nadroparin was 0.19 ± 0.07 IU/mL. Of all patients, 32% had anti-Xa levels below the prophylactic range. Anti-Xa activity inversely correlated with TBW (correlation coefficient - 0.410) and lean body weight (LBW; correlation coefficient - 0.447); 67% of patients with a LBW ≥ 80 kg had insufficient anti-Xa activity concentrations. No VTE events occurred.

CONCLUSIONS

In morbidly obese patients, a postoperative dose of 5700 IU of nadroparin resulted in subprophylactic exposure in a significant proportion of patients. Especially in patients with LBW ≥ 80 kg, a higher dose may potentially be required to reach adequate prophylactic anti-Xa levels.

Differences in Body Composition in Patients with Obesity 1 Year After Roux-En-Y Gastric Bypass: Successful Vs. Unsuccessful Weight Loss

AIM

The aim of this study is to compare the differences in body composition in patients with obesity with successful weight loss (SWL) and unsuccessful (USWL) 1 year after Roux-en-Y gastric bypass (RYGB).

METHODS

We included 36 women and 22 men. After stratifying patients according with SWL (defined as ≥ 50% of excess weight loss), fat-free mass (FFM) and fat mass (FM) trajectories were analyzed in each group.

RESULTS

The %FM in SWL women (78%) was lower than USWL (36 vs. 44, p < 0.001). The %FM in SWL men (77%) was lower than USWL (27 vs. 38, p < 0.05). A lower %FM before surgery increased the probability of success (p < 0.05).

CONCLUSIONS

SWL patients have a lower %FM, and those with lower pre-surgical %FM are more likely to have SWL 1 year after RYGB.