Bone Metabolism in Adolescents and Adults Undergoing Roux-En-Y Gastric Bypass: a Comparative Study

Changes in Nutritional Outcomes After Roux-en-Y Gastric Bypass: A Systematic Review and Meta-Analysis

BACKGROUND

Bariatric surgery (BS) is the most effective treatment for severe obesity and it has beneficial effects on glycemic control and metabolism outcomes. However, the effects of BS on nutritional outcomes are controversial. Therefore, we aimed to evaluate the changes in several nutritional outcomes after Roux-en-Y gastric bypass (RYGB).

METHODS

A comprehensive search was performed using the following databases: PubMed, Embase, Web of Science, Cochrane Library, WanFang and Chinese National Knowledge Infrastructure. The following outcomes were evaluated: vitamin A, 25-hydroxyvitamin D [25(OH)D], calcium, phosphorus, parathormone (PTH), iron, ferritin, vitamin B12, folate, and zinc. The pooled outcomes were expressed as standard mean difference (SMD) and 95% confidence interval (CI) using a random effects model.

RESULTS

Fifty-six studies including 5645 individuals with obesity met the inclusion criteria. Serum 25(OH)D (SMD = 0.78, 95%CI 0.38 to 1.20, P < 0.001), phosphorus (SMD = 0.48, 95%CI 0.22 to 0.74, P < 0.001), PTH (SMD = 0.35, 95%CI 0.11 to 0.59, P = 0.005), vitamin B12 (SMD = 1.11, 95%CI 0.41 to 1.80, P = 0.002), and folate (SMD = 1.53, 95%CI 0.77 to 2.28, P < 0.001) significantly increased after RYGB compared with the baseline. Serum ferritin (SMD =  - 1.67, 95%CI - 2.57 to - 0.77, P < 0.001), vitamin A (SMD =  - 0.64, 95%CI - 0.99 to - 0.29, P < 0.001), and plasma zinc (SMD =  - 0.58, 95%CI - 1.09 to - 0.06, P = 0.027) significantly decreased after RYGB. No significant changes in serum calcium (SMD =  - 0.14, 95%CI - 0.40 to 0.11, P = 0.219) and iron (SMD = 0.26, 95%CI - 0.11 to 0.64, P = 0.165) were observed after RYGB.

CONCLUSIONS

Despite the increased levels of 25(OH)D, phosphorus, vitamin B12 and folate, this meta-analysis revealed the unfavorable nutritional consequences after RYGB.

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.

Body Composition Changes in Adolescents Who Underwent Bariatric Surgery: A Systematic Review and Meta-analysis

PURPOSE OF REVIEW

The purpose of this review and meta-analysis is to characterize the changes in body composition of children and adolescents who underwent bariatric surgery and identify possible negative effects of performing this procedure during pediatric ages.

RECENT FINDINGS

Bariatric surgery in children and adolescents is an emerging strategy to promote higher and faster body weight and fat mass losses. However, possible negative effects usually observed in surgical patients' muscle-skeletal system raise a major concern perform this intervention during growth. Despite these possible issues, most experimental studies and reviews analyze bariatric surgery's effectiveness only by assessing anthropometric outcomes such as body weight and BMI, disregarding the short- and long-term impact of bariatric surgery on all body composition outcomes. Bariatric surgery is effective to reduce fat mass in adolescents, as well as body weight, waist circumference, and BMI. Significant reduction in lean mass and fat-free mass is also observed. Bone mass seems not to be impaired. All outcomes reduction were observed only in the first 12 months after surgery. Sensitivity analysis suggests possible sex and type of surgery-related differences, favoring a higher fat mass, body weight, and BMI losses in boys and in patients who underwent RYGB.

Nutrient Deficiency After Bariatric Surgery in Adolescents: A Systematic Review and Meta-Analysis

OBJECTIVE

This systematic review and meta-analysis study aimed to estimate changes in blood nutrient concentrations and nutrient deficiencies in adolescents following bariatric surgery.

METHODS

We searched PubMed, Scopus, and the Web of Science to find studies published between January 2000 and August 2023. Observational studies reporting the mean blood concentration of nutrients before and after bariatric surgery or the proportion of nutrient deficiencies after the surgery in healthy adolescents were selected.

RESULTS

Fifteen studies were included. Gastric bypass and sleeve gastrostomy were the most common types of surgery. Vitamin D, iron, or ferritin, vitamin B12, calcium, and folic acid were the most studied nutrients, respectively. Other nutrients examined in the studies included zinc, phosphorus, and albumin. The serum ferritin increased by 21 mcg/L (95% CI = 10.0, 32.0 mcg/L) after the surgery, but there were no significant alterations in other nutrients. The postoperative prevalence of low albumin, ferritin, vitamin D, and vitamin B12 levels was 10%, 49%, 41%, and 20%, respectively. Also, 23% had an iron deficiency, and 10% had a calcium deficiency after bariatric surgery.

CONCLUSIONS

The serum ferritin level increased following bariatric surgery in adolescents. Vitamin D and ferritin deficiencies were estimated to be present in more than one-third of adolescents after the surgery.

Change in Mineral Status After Bariatric Surgery: a Meta-analysis

BACKGROUND

The risk of protein and vitamin deficiencies after bariatric surgery has been well studied, but the change in mineral status has not gotten enough attention. This study aimed to perform a meta-analysis regarding the change in mineral levels after bariatric surgery and the prevalence of postoperative mineral deficiency, with subgroup analyses of different surgical procedures, study regions, and follow-up time.

METHODS

CENTRAL, PubMed, and EMBASE were searched for related articles. Meta-analysis, subgroup analysis, and sensitivity analysis were performed if necessary.

RESULTS

A total of 107 articles with 47,432 patients were included. The most severe mineral deficiency after bariatric surgery was iron (20.1%), followed by zinc (18.3%), copper (14.4%), chlorine (12.2%), phosphorus (7.5%), and calcium (7.4%). Serum concentrations of potassium, sodium, selenium, manganese, and molybdenum showed no significant change before and after surgery. Subgroup analyses revealed that SG had fewer deficiencies in serum iron, calcium, zinc, magnesium, phosphorus, copper, and selenium than RYGB. OAGB showed a higher incidence of serum iron and zinc deficiencies than RYGB. Studies conducted in different regions also found various mineral statuses after surgery. Studies with follow-up ≥ 5 years had a lower prevalence of zinc, copper, and selenium deficiencies than follow-up < 5 years.

CONCLUSION

A high deficiency rate of serum iron, zinc, copper, chlorine, phosphorus, and calcium was seen after bariatric surgery. The difference in surgical procedures, study regions, and follow-up time may affect postoperative mineral status; more targeted mineral supplement programs are needed considering these influencing factors.

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

Introduction

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

Objective

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

Methods

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

Results

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

Conclusions

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

The impact of preoperative vitamin administration on skeletal status following sleeve gastrectomy in young and middle-aged women: a randomized controlled trial

BACKGROUND

The appropriate strategies to minimize skeletal deterioration following bariatric surgeries are inconclusive. This randomized controlled trial evaluated the effect of preoperative vitamin supplementation on bone mineral density (BMD) and biochemical parameters in females post-sleeve gastrectomy (SG).

METHODS

Participants were randomized to a 2-month preoperative treatment with a multivitamin and vitamin D 4000 IU/d (intervention arm) or 1200 IU/d (control arm). Preoperative and 12-month postoperative follow-up evaluations included anthropometrics, biochemical parameters, and dual energy X-ray absorptiometry (DEXA).

RESULTS

Sixty-two females (median age 29.7 years and median BMI 43.4 kg/m²) were recruited, 87% completed the 12-month follow-up. For the intervention and control arms, significant and similar reductions at 12-months post-surgery were observed in BMD of the hip (-6.8 ± 3.7% vs. -6.0 ± 3.6%; P = 0.646) and of the femoral neck (-7.1 ± 5.8% vs. -7.2 ± 5.5%; P = 0.973). For the intervention compared to the control arm, the 25 hydroxyvitamin D (25(OH)D) increment was greater after 2 months treatment, and vitamin D deficiency rates were lower at 3 and 6-months follow-up (P < 0.016). However, at 12-months postoperative, 25(OH)D values and vitamin D deficiency were comparable between the arms (P > 0.339). Predictors for BMD decline in the total hip were the percentage of excess weight-loss, age>50 years, and lower initial BMI (P ≤ 0.003).

CONCLUSIONS

SG was associated with a significant decline in BMD of the hip and femoral neck in young and middle-aged women, and was unaffected by preoperative vitamin D supplementation. Females who are peri-menopausal or with greater postoperative weight-loss should be particularly followed for BMD decline.

Treatment of type 2 diabetes in children: what are the specific considerations?

Introduction: The number of individuals under 18 years of age with type 2 diabetes is increasing at an alarming rate worldwide. These patients are often characterized by obesity and they often experience a more rapid disease progression than adults with type 2 diabetes. Thus, focus on prevention and management of complications and comorbidities is imperative. With emphasis on weight loss and optimal glycemic control, treatment includes lifestyle changes and pharmacotherapy, which in this patient group is limited to metformin, liraglutide and insulin. In selected cases, bariatric surgery is indicated.Areas covered: This perspective article provides an overview of the literature covering pathophysiology, diagnosis, characteristics and treatment of pediatric type 2 diabetes, and outlines the gaps in our knowledge where further research is needed. The paper draws on both mechanistic studies, large scale intervention trials, epidemiological studies and international consensus statements.Expert opinion: Type 2 diabetes in pediatric patients is an increasing health care problem, and the current treatment strategies do not successfully meet the many challenges and obstacles in this patient group. Treatments must be early, intensive, multifaceted and durable. Also, prevention of obesity and type 2 diabetes in at-risk children should be addressed and prioritized on all levels.

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

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

Vitamin D Status After Gastric Bypass or Sleeve Gastrectomy over 4 Years of Follow-up

BACKGROUND

Bariatric surgery for severe obesity can lead to micronutrient/vitamin deficiencies.

AIMS

To study baseline and post-surgical prevalence of vitamin D deficiency in patients undergoing bariatric surgery.

PARTICIPANTS AND SETTING

Patients undergoing bariatric surgery in a university teaching hospital in North West England.

METHODS

We performed an observational cohort analysis of longitudinal data on vitamin D and related parameters in patients who underwent bariatric surgery. Patients were routinely recommended daily combined calcium and vitamin D supplementation post-surgery.

RESULTS

We studied 460 patients who had completed at least 12 months post-operatively; mean (standard deviation) age was 48.0 (10.5) years, weight 144.7 (27.3) kg and body mass index 50.0 (7.6) kg/m²; 292 (63.5%) underwent gastric bypass and 168 (36.5%) sleeve gastrectomy. Vitamin D level was 33.1 (23.9) nmol/L at baseline, rising to 57.1 (23.1) nmol/L at 12 months post-surgery. Whereas 43.2% had vitamin D deficiency and 34.7% insufficiency preoperatively, 8.9% and 26.7% had deficiency and insufficiency, respectively, at 12 months with similar trends up to 4 years of follow-up. There were no significant differences between procedures or sexes in vitamin D levels or sufficiency rates.

CONCLUSION

Vitamin D deficiency and insufficiency were prevalent pre-surgery and reduced significantly with routine supplementation post-surgery.

Bone Metabolism in Adolescents Undergoing Bariatric Surgery

PURPOSE

The prevalence of childhood obesity has increased over past decades with a concomitant increase in metabolic and bariatric surgery (MBS). While MBS in adults is associated with bone loss, only a few studies have examined the effect of MBS on the growing skeleton in adolescents.

METHODS

This mini-review summarizes available data on the effects of the most commonly performed MBS (sleeve gastrectomy and gastric bypass) on bone in adolescents. A literature review was performed using PubMed for English-language articles.

RESULTS

Dual-energy x-ray absorptiometry (DXA) measures of areal bone mineral density (aBMD) and BMD Z scores decreased following all MBS. Volumetric BMD (vBMD) by quantitative computed tomography (QCT) decreased at the lumbar spine while cortical vBMD of the distal radius and tibia increased over a year following sleeve gastrectomy (total vBMD did not change). Reductions in narrow neck and intertrochanteric cross-sectional area and cortical thickness were observed over this duration, and hip strength estimates were deleteriously impacted. Marrow adipose tissue (MAT) of the lumbar spine increased while MAT of the peripheral skeleton decreased a year following sleeve gastrectomy. The amount of weight loss and reductions in lean and fat mass correlated with bone loss at all sites, and with changes in bone microarchitecture at peripheral sites.

CONCLUSION

MBS in adolescents is associated with aBMD reductions, and increases in MAT of the axial skeleton, while sleeve gastrectomy is associated with an increase in cortical vBMD and decrease in MAT of the peripheral skeleton. No reductions have been reported in peripheral strength estimates.

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.