Short-Term Changes on Body Composition and Bone Mass After One-Anastomosis Gastric Bypass: a Prospective Observational Study

Effect of regional body composition changes on bone density remodeling after sleeve gastrectomy

Background

Sleeve gastrectomy (SG) results in bone mineral density (BMD) loss and varying body composition parameters. However, the effects of body compositions on bone health are controversial. In order to accurately demonstrate their relationship and provide new insights into the causes of BMD loss after sleeve gastrectomy, this study is aimed to investigate the role of changes in body composition in BMD loss 12 months after SG.

Methods

41 Chinese individuals with obesity (25 women and 16 men) who underwent SG were prospectively examined for at least 12 months. Measurements of anthropometrics, body composition, BMD and blood samples were collected.

Results

For 12 months, the femoral neck (FN) BMD and total hip (TH) BMD decreased significantly compared with baseline in both sexes but not lumbar spine (LS) BMD. Greater TH BMD loss was observed in men than in women. For the first 6 months post-SG, the FN BMD loss was positively associated with the estimated fat free mass index (eFFMI) reduction in women (adjusted β = 0.77, P = 0.004) and positively associated with reduction of subcutaneous fat area (SFA) in men (r = 0.931, P = 0.007). For 12 months post-SG, the FN BMD loss was negatively associated with visceral fat area (VFA) reduction in women (adjusted β = -0.58, P = 0.027) and men (adjusted β = -0.68, P = 0.032). TH BMD loss was positively associated with waist circumference reduction in women (r = 0.448, P = 0.028).

Conclusion

FN and TH BMD decrease after SG in both women and men. The changes in body compositions are associated with BMD loss at different time points and bone sites. Our data emphasize the limitation of simply taking the total weight loss (% TWL) as an influencing factor of bone mineral density and the necessity of delineating body composition in relevant studies.

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

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

Generation and characterization of a mouse model for one anastomosis gastric bypass surgery

One anastomosis gastric bypass (OAGB) surgery became a common bariatric procedure in recent years. In this surgery, the distal stomach, duodenum, and proximal jejunum are bypassed, leading to weight loss, improvement in metabolic parameters, and a change in hormonal secretion. We sought to generate and characterize a mouse model for OAGB. Mice fed for 26 wk on a high-fat diet were assigned to OAGB, sham surgery, or caloric restriction and were followed for 50 more days on a high-fat diet. Physiological and histological parameters of the mice were compared during and at the end of the experiment. OAGB-operated mice lost weight and displayed low levels of plasma lipids, high insulin sensitivity, and rapid glucose metabolism compared with sham-operated mice. OAGB-operated mice had higher energy expenditure, higher levels of glucagon-like peptide (GLP-1), and lower albumin than weight-matched calorie-restricted mice. There was no difference in the histology of the endocrine pancreas. The livers of OAGB mice had little hepatic steatosis yet presented with a large number of phagocytic cells. The OAGB mouse model recapitulates many of the phenotypes described in patients that underwent OAGB and enables molecular and physiological studies on the outcome of this surgery.NEW & NOTEWORTHY A mouse model for one anastomosis gastric bypass (OAGB) surgery displays similar outcomes to clinical reports and enables to study the weight loss-dependent and -independent effects of this bariatric surgery.

Short-Term Changes on Body Composition After Sleeve Gastrectomy and One Anastomosis Gastric Bypass

Introduction: Changes in body composition after different bariatric surgeries have been studied extensively, but most of them have emphasized on Roux-en-Y gastric bypass. Only a few studies have assessed the effects of sleeve gastrectomy (SG). Also, the effect of one anastomosis gastric bypass (OAGB) on body composition is not fully apprehended. Furthermore, there is no agreement on how much fat-free mass (FFM) loss is tolerable in weight loss interventions. Therefore, we decided to assess the reduction in fat mass (FM) and FFM at 1, 3, 6, and 12 months after two types of bariatric surgery in a single center. Methods: In the current retrospective cross-sectional study, the patients' hospital records were analyzed. We included patients who had SG or OAGB and a complete 1-year follow-up record. We recorded demographic data as well as weight, body mass index (BMI), FM, and FFM before and at 1, 3, 6, and 12 months after surgery in a predesigned checklist. Results: We analyzed 311 patients (43 males and 268 females) in the SG (N = 192, 61.7%) and OAGB (N = 119, 38.3%) groups. Both the SG and OAGB groups demonstrated a statistically significant reduction in weight, BMI, FM, and FFM indices at 12 months after the intervention (P < .001). Moreover, no statistically significant difference was observed between the SG and OAGB groups regarding the mean of all body composition indices at 3, 6, and 12 months after the intervention. Conclusion: We found that SG and OAGB effectively decreased weight and body composition indices, comprising FM and FFM, with no significant difference between each other.

Body Composition Changes Following Sleeve Gastrectomy Vs. One-Anastomosis Gastric Bypass: Tehran Obesity Treatment Study (TOTS)

PURPOSE

This study aimed to evaluate body composition changes and the determinants of fat-free mass loss (FFML) up to 3 years after sleeve gastrectomy (SG) and one-anastomosis gastric bypass (OAGB).

MATERIALS AND METHODS

A prospective study was conducted on 3864 patients with severe obesity who underwent either SG (2746, 76.1% women, mean age: 39.2 ± 11.6 years, and BMI: 44.3 ± 5.6 kg/m2) or OAGB (1118, 82.2% women, age: 39.9 ± 10.7 years, BMI: 45.6 ± 6.3 kg/m2). Body composition parameters were measured by bioelectrical impedance analysis preoperatively and 1, 3, 6, 9, 12, 18, 24, and 36 months after surgery. Changes in body composition were assessed using the propensity matched generalized estimated equation (GEE) method. The determinants of fat-free mass loss/weight loss (FFML/WL%) were defined using a mixed-model GEE analysis.

RESULTS

Means of FM, FFM, and FFML/WL% decreased significantly in both study groups (Ptrend < 0.001). Changes in BMI, EWL%, FM, and FFML/WL% were different between the two groups (Pbetween < 0.05). The results showed a better FFM preservation and a greater FM loss over time in the OAGB group compared to the SG group (Pinteraction < 0.05). FFML during the first 3 months was greater in the SG compared to the OAGB group (P < 0.001). SG surgery, higher preoperative BMI, and female gender were associated with greater FFML/WL%.

CONCLUSION

In the SG compared to the OAGB group, FFML was greater, especially early after the surgery, emphasizing the need for therapeutic interventions such as regular exercise programs and dietary intake modifications.

How Does Fat Mass Change in the First Year After Bariatric Surgery? A Systemic Review and Meta-Analysis

This systematic review and meta-analysis investigated the time-course effect of different type of bariatric surgeries (BS) up to 1 year post-surgery on fat mass (FM) and body fat percentage (BFP) in patients with morbid obesity. We searched PubMed, Scopus, EMBASE, ISI web of science, and Cochrane databases from October 2002 until May 2020 with no restriction in the English language, to find studies examining the effect of BS on FM (kg) and BFP (%) in morbid obese patients. Meta-analysis of 103 studies carried out on data of 18,166 and 14,575 morbid obese patients following BS, showed that BS was associated with a substantial decrease in FM and BFP, respectively, in 1 month (- 8.17 kg [95% CI - 9.07, - 7.27] and - 1.51% [95% CI - 2.56, - 0.46]), 3 months (- 15.75 [95% CI - 17.49, - 14.0] and - 4.90 [95% CI - 5.97, - 3.83]), 6 months (- 22.51 [95% CI - 23.93, - 21.09] and - 8.56% [95% CI - 9.63, - 7.49]), and 12 months (- 29.69 [95% CI - 31.3, - 28.09] and - 13.49% [95% CI - 14.52, - 12.40]) after the surgery. In conclusion, BS was associated with sustained declines in FM and BFP, from 1 to 12 months, with no indication of plateau phase post-surgery post-operatively. The present study emphasizes that post-bariatric care should have more focus on FM loss during 1-year post-surgery to identify the patients at risk for fat loss plateau.