Effects of omega-loop gastric bypass on vitamin D and bone metabolism in morbidly obese bariatric patients

Oral vitamin D supplementation for adults with obesity undergoing bariatric surgery

BACKGROUND

Vitamin D deficiency following bariatric surgery is common and is expected to be associated with a deleterious impact on the skeleton. However, the benefits of vitamin D supplementation and the optimal dose in this population is currently unknown. The available guidelines on the topic are derived from experts' opinions, and are not evidence based.

OBJECTIVES

To compare the effects of different doses of vitamin D supplementation (low dose (less than 600 international units (IU)/day), moderate dose (600 IU/day to 3500 IU/day), high dose (greater than 3500 IU/day)) to each other or to placebo in adults living with obesity undergoing bariatric surgery.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, LILACS, two trial registries, and the reference lists of systematic reviews, articles, and health technology assessment reports without language restrictions. The last search of all databases was 27 June 2023, except Embase, which we searched on 14 August 2015.

SELECTION CRITERIA

We included randomised controlled trials or controlled clinical trials on vitamin D supplementation comparing different doses or comparing vitamin D to placebo in people undergoing bariatric surgery.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Primary outcomes were fractures and adverse events. Secondary outcomes were vitamin D status, all-cause mortality, bone mineral change, secondary hyperparathyroidism, health-related quality of life, and muscle strength. We used GRADE to assess the certainty of the evidence for each outcome in each comparison.

MAIN RESULTS

We identified five trials with 314 participants. We included three trials in the quantitative analysis. Moderate-dose vitamin D compared to placebo One trial compared moderate-dose vitamin D (3200 IU/day) to placebo. Moderate-dose vitamin D, compared to placebo, may improve vitamin D status and may result in little to no difference in the achieved parathyroid hormone level (achieved 25-hydroxyvitamin D level: mean difference (MD) 13.60 ng/mL, 95% confidence interval (CI) 7.94 to 19.26; achieved parathyroid hormone level: -6.60 pg/mL, 95% CI -17.12 to 3.92; 1 study, 79 participants; low-certainty evidence). The trial reported no adverse events in the moderate-dose vitamin D arm, but did not provide any information on adverse events in the placebo arm. There were no data on fractures, all-cause mortality, bone density change, health-related quality of life, and muscle strength. High-dose vitamin D compared to moderate-dose vitamin D Two trials in Roux-en-Y gastric bypass compared moderate-dose (equivalent dose 800 IU/day to 2000 IU/day) to high-dose (equivalent dose 5000 IU/day to 7943 IU/day) vitamin D. The evidence of high-dose vitamin D on adverse events is very uncertain (risk ratio (RR) 5.18, 95% CI 0.23 to 116.56; 2 studies, 81 participants; very low-certainty evidence). High-dose vitamin D may increase 25-hydroxyvitamin D levels compared to a moderate dose at 12 months, but the evidence is very uncertain (MD 15.55 ng/mL, 95% CI 3.50 to 27.61; I2 = 62%; 2 studies, 73 participants; very low-certainty evidence). High-dose vitamin D may have little to no effect on parathyroid hormone levels compared to a moderate dose at 12 months, but the evidence is very uncertain (MD 2.15 pg/mL, 95% CI -21.31 to 17.01; I2 = 0%; 2 studies, 72 participants; very low-certainty evidence). High-dose vitamin D may have little to no effect on mortality and bone mineral density at the lumbar spine, hip, and forearm, but the evidence is very uncertain. There were no data on fractures, health-related quality of life, or muscle strength.

AUTHORS' CONCLUSIONS

No trials reported on fractures and the evidence available on adverse events is scarce. Moderate-dose vitamin D may improve vitamin D status and may result in little to no improvement in parathyroid hormone levels compared with placebo. High-dose vitamin D supplementation (greater than 3500 IU/day) may increase 25-hydroxyvitamin D levels, and may have little to no effect on parathyroid hormone levels, compared to a moderate dose, but the evidence for both is very uncertain. The currently available limited evidence may not have a significant impact on practice. Further studies are needed to explore the impact of vitamin D supplementation on fractures, adverse events, and musculoskeletal parameters in people undergoing bariatric surgery.

[Postoperative management]

Bariatric surgery results in significant weight loss, reduction or even remission of obesity-associated comorbidities, reduced mortality, and improved quality of life in many patients; however, obesity is a chronic disease, thus follow-up care is required after bariatric surgery. Furthermore, specific issues, such as micronutrient deficiencies and subsequent complications, can arise both in the short-term and the long-term. Abdominal pain after bariatric surgery must always be regarded as a serious symptom. A further focus should be on the diagnosis and treatment of dumping syndrome. Patients with type 2 diabetes should be regularly screened for recurrent hyperglycemia as well as specific sequelae, even though blood glucose levels may be substantially improved or normalized. In addition to centers with multidisciplinary teams, primary care and, in particular, general practitioners will play an increasingly more important role in the follow-up care after bariatric surgery.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Bariatric surgery and secondary hyperparathyroidism: a meta-analysis

BACKGROUND

Obesity increases the risk of obesity-related medical problems. Weight loss after metabolic and bariatric surgery (MBS) has been well studied. However, the effects of MBS on parathyroid function remain unclear.

OBJECTIVE

The objective of this study was to perform a meta-analysis to examine the impact of MBS on the risk of secondary hyperparathyroidism (SHPT).

SETTING

The Second Xiangya Hospital, Central South University, Changsha, Hunan, China.

METHODS

The PubMed, Embase, Web of Science, and the Cochrane Library databases were systematically reviewed from inception to May 2022 to identify studies reporting quantitative measurements of SHPT risk pre-MBS and post-MBS. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were estimated and compared. Effects were pooled using a random-effects or fixed-effects model. Subgroup analyses were performed according to the follow-up time and surgical procedure.

RESULTS

The final meta-analysis included 9 studies with a total of 5585 patients. The mean follow-up time was 3.5 years (range 0.25-5). Overall, MBS appears to does not affect SHPT risk (OR = 1.34, 95% CI 0.81-2.20, I² = 95%). Follow-up data showed no evidence of SHPT within 2 years following gastric bypass (GB) and sleeve gastrectomy procedures (OR = 1.42, 95% CI 0.66-3.07 for GB, OR = 0.39, 95% CI 0.09-1.62 for sleeve gastrectomy ). At the 2-year and long-term follow-up intervals, a marked increase in SHPT was detected for GB (OR = 6.06, 95% CI 3.39-10.85 for GB). In addition, the surgical procedure for GB decreased the likelihood of SHPT compared with the surgical procedure for biliopancreatic diversion with duodenal switch (OR = 0.29, 95% CI 0.17-0.49).

CONCLUSIONS

Our meta-analysis indicated that GB appears to increase SHPT risk. Patients undergoing MBS should be aware of the risk of SHPT. Larger studies are needed to evaluate the outcomes and side effects and may eventually provide a better and more comprehensive understanding of the risks.

Nutritional consequences of endoluminal gastroplasty in the treatment of morbidly obese patients

BACKGROUND

The Endoscopic sleeve gastroplasty (ESG) is one of the new advanced restrictive techniques of bariatric endoscopy. The principle of this bariatric technique is the reduction of stomach volume through endoscopic plication. The long-term efficacy and metabolic effects of this procedure are the subject of this study.

METHODS

20 patients were enrolled; four men, sixteen women. Then they were followed for 24 months in terms of glycemic control, body composition, vitamin, and nutritional status. Observed parameters included glucose, triacylglycerols, high- and low-density lipoprotein cholesterol, micro and macro nutrients, fat mass, and lean body mass.

RESULTS

We observed significant weight loss and a decrease body composition resulted from procedure vs. baseline, with levels of blood glucose also showing statistically significant reductions. The most notable decline in measured values was observed in period six months after the procedure. No significant changes were observed in measurement of micronutrients.

CONCLUSIONS

Good restriction results were obtained following ESG, which might be mediated via altered glucose metabolism. The ESG method has shown a positive effect on fat and muscle mass. Unlike surgical methods, there were no deficits or deficiencies, especially in terms of essential vitamin levels.

IFSO Update Position Statement on One Anastomosis Gastric Bypass (OAGB)

The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) issued a position statement on the role of one anastomosis gastric bypass (OAGB) in the field of bariatric/metabolic surgery in 2018 De Luca et al. (Obes Surg. 28(5):1188-206, 2018). This position statement was issued by the IFSO OAGB task force and approved by the IFSO Scientific Committee and IFSO Executive Board. In 2018, the OAGB task force recognized the necessity to update the position statement in the following 2 years since additional high-quality data could emerge. The updated IFSO position statement on OAGB was issued also in response to inquiries to the IFSO by society members, universities, hospitals, physicians, insurances, patients, policy makers, and media. The IFSO position statement on OAGB has been reviewed within 2 years according to the availability of additional scientific evidence. The recommendation of the statement is derived from peer-reviewed scientific literature and available knowledge. The IFSO update position statement on OAGB will again be reviewed in 2 years provided additional high-quality studies emerge.

Effect of One Anastomosis Gastric Bypass on Haematinics, Vitamin D and Parathyroid Hormone Levels: a Comparison Between 150 and 200 cm Bilio-Pancreatic Limbs

INTRODUCTION

There is little data on the effect of one anastomosis gastric bypass (OAGB) on haematinics, vitamin D and parathyroid hormone levels. It is further unclear if an OAGB with a bilio-pancreatic limb (BPL) of 150 cm (OAGB-150) would deliver better outcomes than that with a BPL of 200 cm (OAGB-200).

MATERIALS AND METHODS

We investigated our records to obtain information on patients who underwent an OAGB-200 or OAGB-150 until 31st July 2018 in our unit.

RESULTS

A total of 405 patients underwent either an OAGB-200 (n = 234) or OAGB-150 (n = 171). The mean age was 46 ± 10.98 years and 276 (68.1%) were females. The mean preoperative weight and the body mass index (BMI) were 139 ± 29.96 kg and 49 ± 8.14 kg/m² respectively. With OAGB-200, there was a significant increase in anaemia rates at 1 and 2 years compared to preoperative levels with a significant fall in haemoglobin levels. After OAGB-150, there was a significant fall in haemoglobin levels at 1 and 2 years but the increase in anaemia rate was only significant at 2 years. There was a significant increase in PTH levels and the number of abnormal values at 1 and 2 years with OAGB-200. With OAGB-150, PTH changes were significant at 2 years only.

CONCLUSION

We found that both OAGB-200 and OAGB-150 are associated with a significant increase in anaemia and secondary hyperparathyroidism. Our findings should prompt the evaluation of supplementation protocols with higher dosages than we recommend for iron, folate and calcium. Consideration should also be given to evaluating shorter BPL lengths than 150 cm with OAGB.

Effect of one-anastomosis gastric bypass on cardiovascular risk factors in patients with vitamin D deficiency and morbid obesity: A secondary analysis

BACKGROUND AND AIMS

Bariatric patients often suffer from vitamin D (VD) deficiency, and both, morbid obesity and VD deficiency, are related to an adverse effect on cardiovascular disease (CVD) risk. Therefore, we assessed the change of known CVD risk factors and its associations during the first 12 months following one-anastomosis gastric bypass (OAGB).

METHODS AND RESULTS

In this secondary analysis, CVD risk factors, medical history and anthropometric data were assessed in fifty VD deficient (25-hydroxy-vitamin D (25(OH)D) <75 nmol/l) patients, recruited for a randomized controlled trial of VD supplementation. Based on previous results regarding bone-mass loss and the association between VD and CVD risk, the study population was divided into patients with 25(OH)D ≥50 nmol/l (adequate VD group; AVD) and into those <50 nmol/l (inadequate VD group; IVD) at 6 and 12 months (T6/12) postoperatively. In the whole cohort, substantial remission rates for hypertension (38%), diabetes (30%), and dyslipidaemia (41%) and a significant reduction in CVD risk factors were observed at T12. Changes of insulin resistance markers were associated with changes of total body fat mass (TBF%), 25(OH)D, and ferritin. Moreover, significant differences in insulin resistance markers between AVD and IVD became evident at T12.

CONCLUSION

These findings show that OAGB leads to a significant reduction in CVD risk factors and amelioration of insulin resistance markers, which might be connected to reduced TBF%, change in 25(OH)D and ferritin levels, as an indicator for subclinical inflammation, and an adequate VD status. REGISTERED AT CLINICALTRIALS.GOV: (Identifier: NCT02092376) and EudraCT (Identifier: 2013-003546-16).

Changes in Bone Mineral Density Following Weight Loss Induced by One-Anastomosis Gastric Bypass in Patients with Vitamin D Supplementation

BACKGROUND

Little is known about changes in bone mineral density (BMD) following weight loss after one-anastomosis gastric bypass (OAGB) and the role of serum vitamin D and its supplementation on bone metabolism. We evaluated BMD after OAGB as a function of vitamin D supplementation with respect to a minimum threshold of 25-hydroxy-vitamin-D [25(OH)D] concentration, which could prevent or decelerate an eventual bone loss.

METHODS

Fifty bariatric patients who participated in the randomized controlled trial were included in this analysis. BMD and anthropometric measurements by DXA and laboratory parameters were assessed before (T0), at 6 (T6), and 12 months (T12) after surgery.

RESULTS

OAGB resulted in a 36% total body weight loss with a decrease in body fat and an increase in lean body mass. A significant decrease in BMD was seen in lumbar spine by 7%, left hip 13%, and total body 1%, but not in forearm. Bone turnover markers increased significantly but with normal parathyroid hormone concentrations. Weight loss was not associated with changes in BMD. A serum 25(OH)D concentration > 50 nmol/l at T6 and T12 (adequate-vitamin-D-group; AVD) showed a significant lower bone loss, compared to the inadequate-vitamin-D-group (IVD; < 50 nmol/l). Lower bone loss in the left hip showed a strong correlation with higher 25(OH)D concentrations (r = 0.635, p = 0.003).

CONCLUSION

These findings support a dose effect of vitamin D supplementation on bone health and suggest that 25(OH)D concentrations need to be above 50 nmol/l at least during the first postoperative year to decelerate bone loss in patients undergoing OAGB.

CLINICAL TRIAL REGISTRY NUMBER AND WEBSITE

Clinicaltrials.gov (NCT02092376) at https://clinicaltrials.gov /. EudraCT (2013-003546-16) at https://eudract.ema.europa.eu /.

Mini Gastric Bypass-One Anastomosis Gastric Bypass (MGB-OAGB)-IFSO Position Statement

PREAMBLE

The International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) has played an integral role in educating both the metabolic surgical and the medical community at large about the role of innovative and new surgical and/or endoscopic interventions in treating adiposity-based chronic diseases.The mini gastric bypass is also known as the one anastomosis gastric bypass. The IFSO has agreed that the standard nomenclature should be the mini gastric bypass-one anastomosis gastric bypass (MGB-OAGB). The IFSO commissioned a task force (Appendix 1) to determine if MGB-OAGB is an effective and safe procedure and if it should be considered a surgical option for the treatment of obesity and metabolic diseases.The following position statement is issued by the IFSO MGB-OAGB task force and approved by the IFSO Scientific Committee and Executive Board. This statement is based on current clinical knowledge, expert opinion, and published peer-reviewed scientific evidence. It will be reviewed in 2 years.

High Incidence of Secondary Hyperparathyroidism in Bariatric Patients: Comparing Different Procedures

BACKGROUND

Bariatric surgery is an effective therapy for morbid obesity but may reduce calcium absorption and significantly decrease the bone mineral density. This study examined the prevalence of secondary hyperparathyroidism (SHPT) in obese subjects during follow-up after different bariatric surgeries. We investigated predictors of SHPT.

METHODS

We enrolled 1470 obese subjects undergoing bariatric/metabolic surgery with at least 1-year follow-up, including 322 patients undergoing Roux-en-Y gastric bypass (RYGB), 695 undergoing single anastomosis (mini-) gastric bypass (SAGB), 93 undergoing laparoscopic adjustable gastric banding (LAGB), and 360 undergoing sleeve gastrectomy (SG). Five years of data were available for 215 patients. Patients were instructed to supplement their diet according to the guideline. Calcium, parathyroid hormone (PTH), and vitamin D levels were measured before surgery and at 1 and 5 years after surgery. SHPT was defined as PTH > 69 pg/mL.

RESULTS

The overall prevalence of SHPT was high, 21.0% before surgery and was not different between patients with different bariatric procedures. Pre-operative PTH correlated with age, BMI, and vitamin D levels. Multi-variate analysis confirmed that vitamin D level was the only independent predictor of SHPT before surgery. The prevalence of SHPT increased to 35.4% at 1 year after surgery and 63.3% at 5 years after surgery. SAGB had the highest prevalence of SHPT (50.6%) followed by RYGB (33.2%), LAGB (25.8%), and SG (17.8%) at 1 year after surgery. At 5 years after surgery, SAGB still had the highest prevalence of SHPT (73.6%), followed by RYGB (56.6%), LAGB (38.5%), and SG (41.7%). Serum PTH at 1 year after surgery correlated with decreased BMI and weight loss. Multi-variate analysis confirmed that age, sex, calcium level, and bypass procedure were independent predictor of SHPT after surgery.

CONCLUSIONS

The prevalence of SHPT is high in morbidly obese patients before bariatric surgery which is related to vitamin D deficiency. The prevalence of SHPT increased continually along with the time after bariatric surgery, especially in patients receiving SAGB, followed by RYGB. The supplementation of vitamin D and calcium have to be higher in bypass procedure, especially in malabsorptive procedure.

Vitamin D3 Loading Is Superior to Conventional Supplementation After Weight Loss Surgery in Vitamin D-Deficient Morbidly Obese Patients: a Double-Blind Randomized Placebo-Controlled Trial

Background

Bariatric patients often suffer from vitamin D deficiency (VDD), and both, morbid obesity and VDD, are related to non-alcoholic fatty liver disease. However, limited data are available regarding best strategies for treating VDD, particularly, in bariatric patients undergoing omega-loop gastric bypass (OLGB). Therefore, we examined the efficacy and safety of a forced vitamin D dosing regimen and intervention effects in liver fibrotic patients.

Methods

In this double-blind, randomized, placebo-controlled trial, 50 vitamin D-deficient patients undergoing OLGB were randomly assigned to receive, in the first month postoperatively, oral vitamin D₃ (≤3 doses of 100,000 IU; intervention group) or placebo as loading dose (control group) with subsequent maintenance dose (3420 IU/day) in both groups until 6-month visit.

Results

Compared with control group, higher increase of 25(OH)D (67.9 (21.1) vs. 55.7 nmol/L (21.1); p = 0.049) with lower prevalence of secondary hyperparathyroidism (10 vs. 24 %; p = 0.045) was observed in intervention group. No (serious) adverse events related to study medication were found. The loading dose regimen was more effective in increasing 25(OH)D in patients with significant liver fibrosis while this was not the case for conventional supplementation (placebo with maintenance dose) (71.5 (20.5) vs. 22.5 nmol/L (13.8); p = 0.022; n = 14).

Conclusions

Our findings indicate that a high vitamin D₃ loading dose, in the first month postoperatively, with subsequent maintenance dose is effective and safe in achieving higher vitamin D concentrations in OLGB patients. Unexpectedly, it is more effective in patients with significant liver fibrosis which is of potentially high clinical relevance and requires further investigation.

Electronic supplementary material

The online version of this article (doi:10.1007/s11695-016-2437-0) contains supplementary material, which is available to authorized users.

Practical Recommendations of the Obesity Management Task Force of the European Association for the Study of Obesity for the Post-Bariatric Surgery Medical Management

Bariatric surgery is today the most effective long-term therapy for the management of patients with severe obesity, and its use is recommended by the relevant guidelines of the management of obesity in adults. Bariatric surgery is in general safe and effective, but it can cause new clinical problems and is associated with specific diagnostic, preventive and therapeutic needs. For clinicians, the acquisition of special knowledge and skills is required in order to deliver appropriate and effective care to the post-bariatric patient. In the present recommendations, the basic notions needed to provide first-level adequate medical care to post-bariatric patients are summarised. Basic information about nutrition, management of co-morbidities, pregnancy, psychological issues as well as weight regain prevention and management is derived from current evidences and existing guidelines. A short list of clinical practical recommendations is included for each item. It remains clear that referral to a bariatric multidisciplinary centre, preferably the one performing the original procedure, should be considered in case of more complex clinical situations.

A systematic review of the interrelation between diet- and surgery-induced weight loss and vitamin D status

Obesity is a major global health problem and has been associated with vitamin D deficiency. Intentional weight loss may alter vitamin D status and, conversely, vitamin D supplementation has been hypothesized to aid in weight loss. A systematic literature search in PubMed/Medline identified 3173 articles of which 37 studies (randomized controlled trials (RCT) [n=17], non-RCTs [n=20]) are summarized as effect of: (I) diet-induced weight loss on vitamin D status (n=7), (II) vitamin D supplementation on diet-induced weight loss (n=11), (III) surgery-induced weight loss on vitamin D status (n=15), and (IV) vitamin D supplementation after surgery-induced weight loss on vitamin D status (n=5). While all studies on the effect of diet-induced weight loss on vitamin D status have consistently reported increased vitamin D levels, the targeted percentage of weight loss that is necessary for an increase has varied between 5% and >10%. N=11 RCTs testing the effect of vitamin D supplementation observe that vitamin D supplementation does not result in increased weight loss, but may affect body fat loss. Vitamin D deficiency and subsequent hyperparathyroidism have been detected in post-surgery patients, and there is evidence that vitamin D supplementation improves these post-surgery complications. We review the current evidence addressing the role of vitamin D status and supplementation in diet- and surgery-induced weight loss. Subsequently, we highlight gaps in current research and suggest directions for future research including differences in vitamin D supplementation dosages, indoor vs. outdoor exercise, and the assessment of vitamin D status in different body pools.

Prevalence of Liver Fibrosis and its Association with Non-invasive Fibrosis and Metabolic Markers in Morbidly Obese Patients with Vitamin D Deficiency

BACKGROUND

Morbidly obese patients are at risk for non-alcoholic fatty liver disease (NAFLD) and vitamin D deficiency (VDD). Non-alcoholic steatohepatitis (NASH) is the progressive variant of NAFLD and can advance to fibrosis, cirrhosis, and liver cancer. We aimed to examine prevalence of liver fibrosis and its non-invasive predictors in bariatric patients with VDD (<75 nmol/l).

METHODS

Baseline liver biopsy of a randomized controlled trial was performed in 46 patients with omega loop gastric bypass. Clinical, laboratory, and histological data were examined and tested with univariate and multivariable analysis.

RESULTS

In total, 80 % were females, aged 42 (SD 13) years with BMI 44 (4) kg/m(2). Twenty-six percent had diabetes mellitus (DM) and 44 % metabolic syndrome (MeS). Seventy-two percent had NASH, 11 % simple steatosis, and 17 % normal liver. In total, 30 % demonstrated significant fibrosis (F ≥ 2) with 9 % of advanced (F3) and 4 % cirrhosis (F4). Increased stages of fibrosis were primarily associated with higher levels of HOMA2-insulin resistance (IR), procollagen type I propeptide (P1NP), lower osteocalcin, albumin-corrected calcium, parathyroid hormone, vitamin D, male sex, and higher age. Other independent risk factors for advanced fibrosis were MeS (OR = 9.3 [0.99-87.5], p = 0.052) and DM (OR = 12.8 [1.2-137.4], p = 0.035). The fibrosis FIB-4 index <10.62 and NAFLD fibrosis score <-26.93 had a negative predictive value of 100 and 96 %, respectively.

CONCLUSIONS

Liver fibrosis is frequent in morbidly obese patients with concurrent DM and/or MeS. Increased serum levels of IR, P1NP, lower osteocalcin, and VDD are clinically relevant predictors of fibrosis. Consequently, we suggest that patients with preoperative presence of these markers are at increased risk for liver fibrosis and should be monitored closely.

The Effect of Roux-en-Y vs. Omega-Loop Gastric Bypass on Liver, Metabolic Parameters, and Weight Loss

BACKGROUND

Omega-loop gastric bypass (OLGB) results in weight loss (WL) but data on its impact on liver and glucose metabolism compared to Roux-en-Y gastric bypass (RYGB) is lacking. Therefore, the aim of this study was to compare the development of hepatic and metabolic markers as well as WL between the above-mentioned surgical groups during the first postoperative year.

METHODS

We retrospectively evaluated the respective parameters in non-diabetic morbidly obese patients who underwent either RYGB (n = 25) or OLGB (n = 25).

RESULTS

Compared to RYGB, OLGB showed a greater WL percentage. Liver transaminases dropped in RYGB, while rose in OLGB. No correlation between aspartate transaminase, alanine transaminase, and WL could be detected. Gamma-glutamyltransferase decreased significantly in RYGB over the first 3 months, while it increased in OLGB. We found higher levels of triglycerides, insulin, homeostasis model assessment of insulin resistance (HOMA2-IR), and liver fat percentage in RYGB at baseline, despite matching the groups for age, sex, and BMI. Those differences disappeared, except for triglycerides, within 1 year. All metabolic parameters correlated with WL.

CONCLUSION

OLGB results in greater WL but transiently deteriorated several liver parameters in the first postoperative year. This was not associated with WL. The impact of these results on hepatic outcomes such as non-alcoholic steatohepatitis and fibrosis progression requires further studies. In both groups, improved insulin resistance and sensitivity were correlated with higher WL and lower liver fat percentage, respectively.

Hypovitaminosis D in bariatric surgery: A systematic review of observational studies

BACKGROUND

Obesity is a public health problem that carries global and substantial social and economic burden. Relative to non-surgical interventions, bariatric surgery has the most substantial and lasting impact on weight loss. However, it leads to a number of nutritional deficiencies requiring long term supplementation.

OBJECTIVES

The aims of this paper are to review 25-hydroxyvitamin D [25(OH)D] status pre and post bariatric surgery, describe the dose response of vitamin D supplementation, and assess the effect of the surgical procedure on 25(OH)D level following supplementation.

METHODS

We searched Medline, PubMed, the Cochrane Library and EMBASE, for relevant observational studies published in English, from 2000 to April 2015. The identified references were reviewed, in duplicate and independently, by two reviewers.

RESULTS

We identified 51 eligible observational studies assessing 25(OH)D status pre and/or post bariatric surgery. Mean pre-surgery 25(OH)D level was below 30ng/ml in 29 studies, and 17 of these studies showed mean 25(OH)D levels ≤20ng/ml. Mean 25(OH)D levels remained below 30ng/ml following bariatric surgery, despite various vitamin D replacement regimens, with only few exceptions. The increase in post-operative 25(OH)D levels tended to parallel increments in vitamin D supplementation dose but varied widely across studies. An increase in 25(OH)D level by 9-13ng/ml was achieved when vitamin D deficiency was corrected using vitamin D replacement doses of 1100-7100IU/day, in addition to the usual maintenance equivalent daily dose of 400-2000IU (total equivalent daily dose 1500-9100IU). There was no difference in mean 25(OH)D level following supplementation between malabsorptive/combination procedures and restrictive procedures.

CONCLUSION

Hypovitaminosisis D persists in obese patients undergoing bariatric surgery, despite various vitamin D supplementation regimens. Further research is needed to determine the optimal vitamin D dose to reach desirable 25(OH)D levels in this population, and to demonstrate whether this dose varies according to the surgical procedure.

The link between obesity and vitamin D in bariatric patients with omega-loop gastric bypass surgery - a vitamin D supplementation trial to compare the efficacy of postoperative cholecalciferol loading (LOAD): study protocol for a randomized controlled trial

Background

Beyond its classical role in calcium homoeostasis and bone metabolism, vitamin D deficiency has been found to be associated with several diseases, including diabetes, non-alcoholic fatty liver disease, and even obesity itself. Importantly, there are limited data on therapeutic strategies for vitamin D deficiency in bariatric patients, and the procedure-specific guidelines may not be sufficient. To improve long-term outcomes, nutritional screening and appropriate supplementation to prevent nutrient deficiencies are urgently needed. Therefore, the aim of this study is to examine effects and safety of a forced dosing regimen of vitamin D versus conventional dose supplementation on vitamin D levels and other parameters in bariatric patients.

Methods/Design

The study includes loading plus repeat dosing compared with repeated administration of vitamin D without a loading dose, according to guidelines, in a prospective, double-blind, randomized controlled trial. Up to a triple oral loading dose is given on day 1, then 2 and 4 weeks after surgery (100,000 IU dose each time), followed by an oral maintenance dose (3420 IU/day). The control group (n = 25) will receive placebo, followed by administration of a standard dose (3420 IU/day). We hypothesize that a significant increase in vitamin D levels will occur in patients in the treatment group (n = 25) by 24 weeks after surgery. Further measurements are aimed at evaluating changes in inflammation, bone turnover, insulin resistance, blood pressure, liver, mental health, and gut microbiota of patients undergoing omega-loop gastric bypass surgery. Furthermore, possible associations between concentrations of vitamin D, the involved enzymes, or vitamin D receptor in adipose and/or liver tissues will be determined.

Discussion

To our knowledge, this trial is the first of its kind with this type of vitamin D supplementation in bariatric patients. Its major strength is the design and implementation of evaluation of influencing factors such as liver function, bone health, inflammation, insulin resistance, blood pressure, symptoms of depression, or microbiota. This alternative vitamin D dosing regimen has the potential to be a safe, fast, evidence-based treatment of vitamin D deficiency in bariatric patients. Owing to the increasing number of bariatric patients, it is also of interest to elucidate the link between obesity and vitamin D.

Trial registration

ClinicalTrials.gov identifier: NCT02092376. Registered on 17 March 2014.