Chronic increase of bone turnover markers after biliopancreatic diversion is related to secondary hyperparathyroidism and weight loss. Relation with bone mineral density

MicroRNAs as Mediators of Adipose Thermogenesis and Potential Therapeutic Targets for Obesity

Obesity is a growing health problem worldwide, associated with an increased risk of multiple chronic diseases. The thermogenic activity of brown adipose tissue (BAT) correlates with leanness in adults. Understanding the mechanisms behind BAT activation and the process of white fat "browning" has important implications for developing new treatments to combat obesity. MicroRNAs (miRNAs) are small transcriptional regulators that control gene expression in various tissues, including adipose tissue. Recent studies show that miRNAs are involved in adipogenesis and adipose tissue thermogenesis. In this review, we discuss recent advances in the role of miRNAs in adipocyte thermogenesis and obesity. The potential for miRNA-based therapies for obesity and recommendations for future research are highlighted, which may help provide new targets for treating obesity and obesity-related diseases.

Adherence to Nutritional Supplementation Determines Postoperative Vitamin D Status, but Not Levels of Bone Resorption Marker, in Sleeve-Gastrectomy Patients

BACKGROUND

Taking advantage of isomeric form of vitamin E in the supplement, adherence to supplement could be evaluated by changes in circulating α- and γ-tocopherol concentrations. Accordingly, effects of supplementation on postoperative nutrition and bone metabolism were studied in terms of adherence.

METHODS

Thirty-eight SG patients were all prescribed a postoperative nutritional supplement containing a low dose of vitamin D (600 IU) and calcium (200 mg). Blood samples were collected prior to (M0) and 6 months after (M6) surgery and concentrations of nutrients and C-terminal telopeptide of type I collage (CTX), a marker of bone resorption, were measured. Adherence and non-adherence were stratified according to change (△, M6-M0) in serum α-tocopherol concentrations (> 0 vs. ≤ 0, respectively).

RESULTS

When M0 and M6 were compared, there were significant increases in serum concentrations of 25(OH)D, α-tocopherol and selenium, whereas there were reductions in parathyroid hormone, ferritin, and γ-tocopherol. At M6, the prevalence of vitamin D insufficiency (25(OH)D < 30 ng/mL) and high CTX were 72 and 26%, respectively. When comparison was made between adherence and non-adherence, only △25(OH)D concentrations, but no other nutrients nor postoperative CTX differed. Multiple linear regression demonstrated that postoperative vitamin D status was independently associated with its preoperative concentrations (β = 0.85, p < 0.001) and adherence (β = 0.52, p < 0.05).

CONCLUSION

SG patients' adherence to supplementation, even with a low dose of vitamin D and calcium, determined vitamin D status but not bone resorption marker concentrations, at least within 6 months after surgery.

Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on Bone Mineral Density in Zucker Diabetic Fatty Rats: A Short-Term Comparative Study

BACKGROUND

While bariatric surgery could result in weight loss as well as glycaemia improvement, the short-term impact on bone health in a high glycemic environment following Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) remains intriguing.

OBJECTIVE

The aim of this study was to compare the short-term effects of RYGB and SG procedures on bone health in Zucker diabetic fatty (ZDFfa/fa) rats.

METHODS

Thirty age-matched male ZDFfa/fa rats were randomized into RYGB, SG, and sham groups after establishment of the diabetic model. Body weight, blood glucose, bone mineral density (BMD), the level of bone turnover markers (BTM), vitamin D, and serum calcium and phosphorus were measured 4 weeks after the operation.

RESULTS

The RYGB procedure brought about lower blood glucose, BMD, serum calcium and phosphorus levels, as well as a relatively higher bone turnover rate and 1,25(OH)2VD level, compared to the SG and sham groups, while the influences of the SG procedure were not significant. 25(OH)VD demonstrated no significant difference among the 3 groups.

CONCLUSIONS

Despite its excellent ability to provide short-term glycemic control, the RYGB procedure could led to more severe impairment of bone health compared to the SG procedure. Bone health should be procured after bariatric surgery, especially with the RYGB procedure. Early detection of BMD and BTM may help to avoid deterioration of bone.

Recommendations for nutritional care after bariatric surgery: Recommendations for best practice and SOFFCO-MM/AFERO/SFNCM/expert consensus

Nutritional care after bariatric surgery is an issue of major importance, especially insofar as risk of deficiency has been extensively described in the literature. Subsequent to the deliberations carried out by a multidisciplinary working group, we are proposing a series of recommendations elaborated using the Delphi-HAS (official French health authority) method, which facilitates the drawing up of best practice and consensus recommendations based on the data of the literature and on expert opinion. The recommendations in this paper pertain to dietary management and physical activity, multivitamin and trace element supplementation and the prevention and treatment of specific deficiencies in vitamins B1, B9, B12, D and calcium, iron, zinc, vitamins A, E and K, dumping syndrome and reactive hypoglycemia.

The increase of osteopontin and β-carboxy-terminal cross-linking telopeptide of type I collagen enhances the risk of hip fracture in the elderly

BACKGROUND

Hip fracture in the elderly is a health burden worldwide due to its high mortality rate. This study was conducted to determine the possible mechanisms of osteopontin (OPN) and β-carboxy-terminal cross-linking telopeptide of type I collagen (β-CTX) in hip fracture in the elderly.

MATERIALS AND METHODS

In the study, we recruited 108 elderly patients with hip fracture diagnosed from May 2012 to May 2015 at the Third Hospital of Xiamen and 86 healthy individuals without a history of hip fracture were taken as controls. Serum levels of OPN and β-CTX were then determined. The T and Z values for bone mineral density (BMD) were also measured. Moreover, logistic regression analysis was performed to assess the risk and protective factors for hip fracture in the elderly.

RESULTS

Serum levels of both OPN and β-CTX were increased in elderly patients with hip fracture. OPN was positively correlated with β-CTX. In addition, the levels of OPN and β-CTX shared a positive association with the age, and a negative association with the BMD, in terms of T and Z values of the hip. In addition, increased BMD and outdoor sports might be protective factors for hip fracture, and an increase in levels of OPN and β-CTX might be associated with a higher risk of hip fracture in the elderly population.

DISCUSSION

Collectively, increased serum levels of OPN and β-CTX might be correlated with a higher risk of a hip fracture and have predictive values in the occurrence of hip fracture in the elderly.

Effects of Biliopancreatic Diversion on Bone Turnover Markers and Association with Hormonal Factors in Patients with Severe Obesity

BACKGROUND

This study evaluated early and medium-term changes in bone turnover markers, and their associations with weight loss, total bone mineral density (BMD), and hormonal changes after biliopancreatic diversion (BPD).

METHODS

Ancillary study from a one-year prospective cohort of 16 individuals assessed before, 3 days, 3 and 12 months after BPD. Bone turnover markers (C-terminal telopeptide (CTX), intact osteocalcin (OC), sclerostin, and osteoprotegerin (OPG)) and several hormones were measured at each visit. Total BMD by DXA was assessed at baseline, 3 and 12 months after BPD. Three participants were lost to follow-up.

RESULTS

CTX increased significantly at 3 days (+ 66%), 3 months (+ 219%), and 12 months (+ 295%). OC decreased at 3 days (- 19%) then increased at 3 months (+ 69%) and 12 months (+ 164%). Change in sclerostin was only significant between 3 days and 3 months (+ 13%), while change in OPG was significant between baseline and 3 days (+ 48%) and baseline and 12 months (+ 45%). CTX increase correlated negatively with weight loss at 3 (r = - 0.63, p = 0.009) and 12 months (r = - 0.58, p = 0.039), and total BMD decrease (r = - 0.67, p = 0.033) at 12 months. Change in insulin and adiponectin correlated with changes in bone turnover markers independently of weight loss.

CONCLUSION

BPD causes an earlier and greater increase in bone resorption over bone formation markers and a decrease in total BMD. Sclerostin did not increase as expected following extensive weight loss. Changes in insulin and adiponectin seem to play a role in the activation of bone remodeling after BPD.

For whom the bell tolls? It is time to retire the classic BPD (bilio-pancreatic diversion) operation

With the culture of safety and lowering risks that took place 20 years ago, sleeve gastrectomy has emerged as a procedure of choice. Hence, for super- and super-super-obese patients, there is a tendency these days to perform surgeries in 2 stages, and sleeve is the procedure of choice. Because sleeve is not part of a classic bilio-pancreatic diversion, it is unlikely that this operation will be done as a second stage, making this operation obsolete.

Beneficial changes on plasma apolipoproteins A and B, high density lipoproteins and oxidized low density lipoproteins in obese women after bariatric surgery: comparison between gastric bypass and sleeve gastrectomy

Background

The beneficial effects in lipid profiles after obesity surgery might be associated with the decrease in cardiovascular risk. However, direct comparison between different surgical techniques has not been extensively performed.

Methods

In the present study we compare 20 obese women submitted to laparoscopic Roux en Y gastric bypass (RYGB) with 20 women submitted to sleeve gastrectomy (SG). Twenty control women matched for age and baseline cardiovascular risk were also included. Both patients and controls were followed up for 1 year after surgery or conventional treatment with diet and exercise, respectively. Lipid profiles were measured at baseline, 6 and 12 months later. Carotid intima-media thickness was measured by ultrasonography at baseline and at the end of the study.

Results

Women submitted to bariatric surgery showed a decrease in total cholesterol, triglycerides, oxidized-LDL and ApoB, and an increase in HDL and ApoA concentrations that occurred regardless of the surgical procedure. LDL concentrations, however, decreased only after RYGB whereas Lp(a) showed no changes. We did not observe any correlation between the changes in serum lipid concentrations and those in carotid intima-media thickness.

Conclusions

Sleeve gastrectomy and gastric bypass induce a similar beneficial effect on serum lipids in women with high cardiovascular risk 1 year after surgery.

Weight loss and bone mineral density in obese adults: a longitudinal analysis of the influence of very low energy diets

Background

The long-term effect of weight reduction on skeletal health is not well understood. The purpose of this study was to examine the impact of an intensive medical weight loss intervention using very low energy diet (VLED) (~ 800 cal/day) that result in significant changes in body weight, on total body bone mineral density (BMD) over 2 years.

Methods

We examined the impact of VLED-induced weight loss on BMD and FFM (Fat-free Mass) after 3–6 months and again while in weight maintenance at 2 years in 49 subjects. The effects of absolute and relative rate of weight reduction assessed by change in weight in kilograms were assessed using general linear modeling, with baseline BMD (or FFM) as a covariate, and age, sex and changes in body weight as primary model predictors.

Results

At the end of 2 years, the average weight loss was greater for men (weight: 23.51 ± 12.5 kg) than women (weight: 16.8 ± 19.2 kg) and BMD loss was greater among women (0.03 ± 0.04 g/cm² vs 0.01 ± 0.04 g/cm²) (all p < 0.05). After adjusting for baseline BMD, age, and sex, there was a small but significant association between total weight loss and 2-year BMD (β = − 0.001 g/cm²; p = 0.01). Similarly, there was a significant independent association between total weight loss and 2-year FFM (β = − 116.5 g; p < 0.01).

Conclusions

Despite significant weight loss with VLED, there was only a small loss is BMD.

Optimisation of follow-up after metabolic surgery

Bariatric surgery has many benefits beyond weight loss, including improved control of glycaemia, blood pressure, and dyslipidaemia; hence, such surgery has been rebranded as metabolic surgery. The operations are, unfortunately, also associated with major surgical and medical complications. The medical complications include gastro-oesophageal reflux disease, malnutrition, and metabolic complications deriving from vitamin and mineral malabsorption. The benefits of surgery can be optimised by implementing specific protocols before and after surgery. In this Review, we discuss the assessment of the risk of major cardiac complications and severe obstructive sleep apnoea before surgery, and the provision of adequate lifelong postsurgery nutritional, vitamin, and mineral supplementation to reduce complications. Additionally, we examine the best antidiabetic medications to reduce the risk of hypoglycaemia after gastric bypass and sleeve gastrectomy, and the strategies to improve weight loss or reduce weight regain. Although optimising clinical pathways is possible to maximise metabolic benefits and reduce the risks of complications and micronutrient deficiencies, evolution of these strategies can further improve the risk-to-benefit ratio of metabolic surgery.

Obesity and bone metabolism

The interaction between obesity and bone metabolism is complex. The effects of fat on the skeleton are mediated by both mechanical and biochemical factors. Though obesity is characterized by higher bone mineral density, studies conducted on bone microarchitecture have produced conflicting results. The majority of studies indicate that obesity has a positive effect on skeletal strength, even though most likely the effects are site-dependent and, in fact, obese individuals might be at risk of certain types of fractures. Mechanical loading and higher lean mass are associated with improved outcomes, whereas systemic inflammation, observed especially with abdominal obesity, may exert negative effects. Weight loss interventions likely lead to bone loss over time. Pharmacological treatment options seem to be safe in terms of skeletal health; however, the skeletal effects of bariatric surgery are dependent on the type of surgical procedure. Malabsorptive procedures are associated with higher short-term adverse effects on bone health. In this narrative review, we discuss the effects of obesity and weight loss interventions on skeletal health.

Predictive Factors of Secondary Normocalcemic Hyperparathyroidism after Roux-en-Y Gastric Bypass

OBJECTIVE

Aim of this study is to evaluate determinants of secondary normocalcemic hyperparathyroidism (SNHPT) persistence in patients who have undergone Roux-en-Y gastric bypass on vertical-banded gastroplasty.

METHODS

226 consecutive patients submitted to bariatric surgery were prospectively enrolled and divided in two groups on the basis of preoperative presence of SNHPT. For each patient, we evaluated anthropometric and laboratory parameters. Calcium metabolism (calcemia, PTH, and 25-hydroxy vitamin D serum levels) was studied before surgery and at 6-month intervals (6, 12, and 18 months) as surgical follow-up.

RESULTS

Based on presurgical SNHPT presence or absence, we defined group 1-201 patients and group 2-25 patients, respectively. Among the group 1, 153 (76%) recovered from this endocrinopathy within 6 months after surgery (group 3), while the remaining 48 patients (24%) had persistent SNHPT (group 4). Comparing the anthropometric and laboratory data of group 3 with group 2, the only statistically significant factor was the elapsed time since a prior effective medically controlled diet that led to a steady and substantial weight loss. We found also a statistically significant difference (p < 0.05) between group 3 and group 4 in term of % of weight loss and PTH levels.

CONCLUSIONS

Patients suitable for bariatric surgery must have history of at least one efficient medically controlled diet, not dating back more than 5 years before surgery. This elapsed time represent the cut-off time within which it is possible to recover from SNHPT in the first semester after Roux-en-Y gastric bypass on vertical-banded gastroplasty. The treatment of vitamin D insufficiency and the evaluation of SNHPT before bariatric surgery should be recommended. The clinical significance of preoperative SNHPT and in particular SNHPT after bariatric surgery remains undefined and further studies are required.

Serum Bioavailable Vitamin D Concentrations and Bone Mineral Density in Women After Obesity Surgery

INTRODUCTION

Low bone mass after obesity surgery may arise as a consequence of chronic malabsorption of calcium and vitamin D. However, we have not found any role of serum 25-hydroxyvitamin D or of polymorphisms in the vitamin D receptor gene in previous studies.

PURPOSE

To investigate the circulating bioavailable 25-hydroxyvitamin D in women after bariatric procedures and its association with bone mass.

PATIENTS AND METHODS

The study consisted of 91 women on follow-up for 7 ± 2 years after bariatric surgery. We measured bone mineral density (BMD), serum parathormone (PTH), 25-hydroxyvitamin D, and vitamin D binding protein (VDBP). All patients were genotyped for two variants in the coding region of VDBP (rs4588 and rs7041). Bioavailable 25-hydroxyvitamin D was calculated in double homozygotes.

RESULTS

We found a negative correlation between bioavailable 25-hydroxyvitamin D and PTH (r = -0.373, P = 0.018), but not with BMD at lumbar spine (r = -0.065, P = 0.682) or hip (r = -0.029, P = 0.857). When adjusting by age, similar results were found for PTH (r = -0.441, P = 0.005), BMD at lumbar spine (r = -0.026, P = 0.874) and hip (r = -0.096, P = 0.561). After multivariate linear regression, forcing bioavailable 25-hydroxyvitamin D into the model resulted in a weak significant association with BMD at the lumbar spine (β = - 0.247, P = 0.025).

CONCLUSIONS

Serum bioavailable 25-hydroxyvitamin D concentrations are not associated with bone mass loss after bariatric surgery in women. The negative association with serum PTH levels suggests that vitamin D supplementation partly improves secondary hyperparathyroidism, yet other mechanisms may contribute to low bone mass after bariatric surgery.

INCREASED BONE TURNOVER IN TYPE 2 DIABETES PATIENTS RANDOMIZED TO BARIATRIC SURGERY VERSUS MEDICAL THERAPY AT 5 YEARS

OBJECTIVE

The aim of our study was to determine the 5-year outcomes of bariatric surgery versus intensive medical therapy on bone turnover in patients with type 2 diabetes mellitus (T2DM) from the STAMPEDE trial.

METHODS

This was an ancillary investigation of a 5-year randomized control trial at a single tertiary care center involving 95 patients aged 48.5 ± 8 years with obesity (body mass index [BMI], 36.5 ± 3.6 kg/m²) and uncontrolled T2DM (glycated hemoglobin 9.3 ± 1.6% [78 mmol/mol]). Patients were randomized to intensive medical therapy (IMT; n = 25), Roux-en-Y gastric bypass (RYGB; n = 37), or sleeve gastrectomy (SG; n = 33) for diabetes treatment. Bone formation marker osteocalcin (OC), bone resorption marker serum C-telopeptide of type 1 collagen (CTX), and intact parathyroid hormone (PTH) were assessed at baseline and 5 years postintervention. Analysis with key clinical parameters and outcomes (i.e., age, menopausal status, gender, weight loss) was performed.

RESULTS

Percent change in CTX at 5 years increased in both surgical groups, by 137 ± 108% in RYGB ( P<.001) and 61.1 ± 90% in SG ( P<.001) compared to 29.8 ± 93% in IMT ( P = .12). OC also increased from baseline in the surgical cohorts, by 138 ± 19% in RYGB ( P<.001) and 71 ± 69% in SG ( P<.001) compared to 43.8 ± 121.1% in IMT ( P = .83). Increases in both CTX and OC correlated linearly with increases in PTH levels in RYGB patients ( P<.001). Increase in CTX correlated with decreased BMI in SG patients ( P = .039).

CONCLUSION

In patients with T2DM, bone turnover remains chronically elevated at 5 years following RYGB, and to a lesser extent in SG patients.

ABBREVIATIONS

BMI = body mass index; BTM = bone turnover marker; CTX = C-telopeptide of type 1 collagen; HbA1c = glycated hemoglobin; IMT = intensive medical therapy; OC = osteocalcin; PPI = proton-pump inhibitor; PTH = parathyroid hormone; RYGB = Roux-en-Y gastric bypass; SG = sleeve gastrectomy; T2DM = type 2 diabetes mellitus; TZD = thiazolidinedione.

Revision of Biliopancreatic Diversion for Side Effects or Insufficient Weight Loss: Codification of a New Procedure

PURPOSE

Addressing the problem of proctologic sequelae after Scopinaro's classical BPD, we elongated the common limb from 50 to 200 cm at the expense of the alimentary limb and simultaneously, with the aim of avoiding weight regain, reduced the gastric pouch from 500 to 40 ml. After increased experience with the new procedure, we observed a favourable tendency towards further weight loss. Thus, we subsequently extended the indication to the procedure to patients with unsatisfactory weight loss after Scopinaro's classical BPD (SBPD).

METHODS

We retrospectively reviewed our clinical experience with the new procedure.

RESULTS

From March 2008 to December 2014, 38 patients were submitted to the revisional procedure. The indication to surgical revision was proctologic in 26 patients and unsatisfactory weight loss in 12. After the revisional procedure, a significant reduction in bowel movements per day was observed, together with a significant reduction in body weight (from preoperative 87.1 ± 21 to 69.2 ± 13.5 kg at post-operative year 1 and 68.1 ± 11.9 kg at year 5; p < 0.001) and a parallel reduction in BMI (from preoperative 33.03 ± 7.6 to 26.8 ± 4.1 at post-operative year 1 and 26.9 ± 2.8 at year 5; p < 0.001). Mean excess BMI percent loss was 49.5 ± 94.6% at post-operative month 3, 76.51 ± 74.9% at year 1 and 76.2 ± 31.3% at year 5. Nutritional and metabolic parameters remained stable. Similar results were observed, analysing separately both groups of patients.

CONCLUSIONS

Our preliminary data suggest that the proposed procedure could represent a safe and effective revisional tool to treat invalidating proctologic sequelae after SBPD, or when weight loss may be deemed unsatisfactory.

Improvement in cardiovascular risk in women after bariatric surgery as measured by carotid intima-media thickness: comparison of sleeve gastrectomy versus gastric bypass

BACKGROUND

Bariatric surgery may diminish cardiovascular risk (CVR) and its associated mortality. However, studies that compare these effects with different techniques are scarce.

OBJECTIVE

To evaluate the changes in CVR as estimated by carotid intima-media thickness (IMT) after obesity surgery in women with high CVR as defined by the presence of metabolic syndrome.

SETTING

Academic hospital.

METHODS

We studied 40 severely obese women, of whom 20 received laparoscopic Roux en Y gastric bypass (RYGB) and 20 received sleeve gastrectomy (SG). Twenty control women matched for age and cardiovascular risk were also included. Patients and controls were evaluated at baseline and 1 year after surgery or conventional treatment with diet and exercise, respectively. Only 18 of the 20 women in the control group were available for analysis after 1 year. None of the women who had bariatric surgery was lost to follow-up.

RESULTS

Mean carotid IMT decreased 1 year after surgery irrespective of the surgical technique used, whereas no changes were observed in the control women who had conventional therapy (Wilks´ λ = .802, P = .002 for the interaction, P = .011 for RYGB versus controls, P = .002 for SG versus controls, P = .349 for RYGB versus SG).

CONCLUSION

Both RYGB and SG decrease CVR as measured by carotid IMT in obese women.

The role of serum osteoprotegerin and receptor-activator of nuclear factor-κB ligand in metabolic bone disease of women after obesity surgery

Metabolic bone disease may appear as a complication of obesity surgery. Because an imbalance in the osteoprotegerin and receptor-activator of nuclear factor-κB ligand system may underlie osteoporosis, we aimed to study this system in humans in the metabolic bone disease occurring after obesity surgery. In this study we included sixty women with a mean age of 47 ± 10 years studied 7 ± 2 years after bariatric surgery. The variables studied were bone mineral density, β-isomer of C-terminal telopeptide of type I collagen cross-links (a bone resorption marker), the bone formation markers osteocalcin and N-terminal propeptide of procollagen 1, serum osteoprotegerin and receptor-activator of nuclear factor-κB ligand. Serum osteoprotegerin inversely correlated with the bone remodeling markers osteocalcin, β-isomer of C-terminal telopeptide of type I collagen cross-links and N-terminal propeptide of procollagen 1. The osteoprotegerin and receptor-activator of nuclear factor-κB ligand ratio also correlated inversely with serum parathormone and osteocalcin. Bone mineral density at the lumbar spine was associated with age (β = -0.235, P = 0.046), percentage of weight loss (β = 0.421, P = 0.001) and osteoprotegerin and receptor-activator of nuclear factor-κB ligand ratio (β = 0.259, P = 0.029) in stepwise multivariate analysis (R ² = 0.29, F = 7.49, P < 0.001). Bone mineral density at the hip site was associated only with percentage of weight loss (β = 0.464, P < 0.001) in stepwise multivariate regression (R ² = 0.21, F = 15.1, P < 0.001). These data show that the osteoprotegerin and receptor-activator of nuclear factor-κB ligand system is associated with bone markers and bone mineral density at the lumbar spine after obesity surgery.

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.

Long-term outcomes after biliopancreatic diversion with and without duodenal switch: 2-, 5-, and 10-year data

BACKGROUND

There are minimal long-term data on biliopancreatic diversion (BPD) with or without duodenal switch (BPD/DS).

OBJECTIVES

To investigate the long-term weight loss, co-morbidity remission, complications, and quality of life after BPD and BPD/DS.

SETTING

An academic, university hospital in the United States.

METHODS

We conducted a retrospective review of patients who underwent BPD or BPD/DS between 1999 and 2011. Outcomes included weight loss measures at 2, 5, and 10-15 years postoperatively; co-morbidity remission; long-term complications; nutritional deficiencies; and patient satisfaction.

RESULTS

One hundred patients underwent BPD (34%) or BPD/DS (64%). Mean preoperative body mass index (BMI) was 50.2 kg/m². Mean follow up was 8.2 years (range: 1-15 yr) with 72% of eligible patients in active follow up at 10-15 years postoperatively. Excess weight loss (EWL) was 65.1% at 2 years, 63.8% at 5 years, and 67.9% at 10-15 years. Approximately 10% higher %EWL was achieved for those with preoperative BMI<50 kg/m² versus≥50 kg/m² and patients who underwent BPD/DS versus BPD. Although co-morbidities improved, 37% of patients developed long-term complications requiring surgery. There were no 30-day mortalities; however, there was one mortality from severe malnutrition. Nutritional deficiencies in fat-soluble vitamins, anemia, and secondary hyperparathyroidism were common. Overall, 94% of patients reported satisfaction with their choice of surgery.

CONCLUSION

This clinical experience supports the long-term positive safety profile and efficacy of BPD and BPD/DS at a single U.S. center. Higher levels of excess weight loss are achieved by patients with a lower preoperative BMI and BPD/DS. Although nutritional deficiencies and postoperative complications are common, patient satisfaction remains high.

Effects of bariatric surgery on male obesity-associated secondary hypogonadism: comparison of laparoscopic gastric bypass with restrictive procedures

Bariatric surgery results in the complete resolution of male obesity-associated secondary hypogonadism (MOSH) in many patients. However, the effects of different bariatric surgical procedures on male sexual hormone profiles and sexual dysfunction have not been compared to date. We compared the pre- and post-operative (at least 6 months after initial surgery) sex hormone profiles of 20 severely obese men submitted to laparoscopic gastric bypass (LGB) with 15 similar patients submitted to restrictive techniques (sleeve gastrectomy in 10 and adjustable gastric banding in 5). We calculated free testosterone (FT) levels from total testosterone (TT) and sex hormone binding globulin (SHBG) concentrations. Fasting glucose and insulin levels served for homeostatic model assessment of insulin resistance (HOMAIR). MOSH was present in 25 and 16 of the 35 patients when considering TT and FT concentrations respectively, resolving after surgery in all but one of them. When considering all obese men as a whole, patients submitted to LGB or restrictive procedures did not differ in terms of excess weight loss, in the decrease of fasting glucose and insulin, HOMAIR and waist circumference, or in the increase of serum 25-hydroxyvitamin D, TT and FT levels. The improvement in TT correlated with the decrease in fasting glucose (r = -0.390, P = 0.021), insulin (r = -0.425, P = 0.015) and HOMAIR (r = -0.380, P = 0.029), and with the increase in SHBG (r = 0.692, P < 0.001). The increase in FT correlated with the decrease in fasting glucose (r = -0.360, P = 0.034). LGB and restrictive techniques are equally effective in producing a remission of MOSH.

Skeletal effects of bariatric surgery: examining bone loss, potential mechanisms and clinical relevance

Bariatric surgery is the most effective therapeutic approach to morbid obesity, resulting in substantial weight loss and improved cardiometabolic profiles; however, a growing body of evidence suggests that bariatric procedures increase both skeletal fragility and the risk of related future fracture secondary to excessive bone loss. Prospective evidence shows that areal bone mineral density (BMD) assessed by dual energy X-ray absorptiometry (DXA) declines by as much as 14% in the proximal femoral regions, including the femoral neck and total hip, 12 months postoperatively. Lumbar spine areal BMD outcomes show greater 12-month postoperative variability across surgical procedures (-8 to +6%) and contrast with no change in volumetric BMD outcomes measured by quantitative computed tomography. Diminished mechanical loading, micronutrient deficiency and malabsorption, along with neurohormonal alterations, offer plausible underlying mechanisms to explain these observed post-bariatric bone changes, but most remain largely unsubstantiated in this population. Importantly, DXA-based skeletal imaging may have limited utility in accurately detecting bone change in people undergoing bariatric surgery; partly because excessive tissue overlying bone increases the variability of areal BMD outcomes. Moreover, a paucity of fracture and osteoporosis incidence data raises questions about whether marked post-bariatric surgery bone loss is clinically relevant or a functional adaptation to skeletal unloading. Future studies that use technology which is able to accurately capture the site-specific volumetric BMD and bone architectural changes that underpin bone strength in people undergoing bariatric surgery, that consider mechanical load, and that better quantify long-term fracture and osteoporosis incidence are necessary to understand the actual skeletal effects of bariatric surgery.

Bone metabolism after bariatric surgery

Bariatric surgery is a popular and effective treatment for severe obesity but may have negative effects on the skeleton. This review summarizes changes in bone density and bone metabolism from animal and clinical studies of bariatric surgery, with specific attention to Roux-en-Y gastric bypass (RYGB), adjustable gastric banding (AGB), and sleeve gastrectomy (SG). Skeletal imaging artifacts from obesity and weight loss are also considered. Despite challenges in bone density imaging, the preponderance of evidence suggests that bariatric surgery procedures have negative skeletal effects that persist beyond the first year of surgery, and that these effects vary by surgical type. The long-term clinical implications and current clinical recommendations are presented. Further study is required to determine mechanisms of bone loss after bariatric surgery. Although early studies focused on calcium/vitamin D metabolism and mechanical unloading of the skeleton, it seems likely that surgically induced changes in the hormonal and metabolic profile may be responsible for the skeletal phenotypes observed after bariatric surgery.

Short- and mid-term changes in bone mineral density after laparoscopic sleeve gastrectomy

BACKGROUND

Bariatric surgery is the most effective treatment for achieving a significant weight loss. Morbidities present a significant reduction after bariatric surgery, but it may also result in several health complications, related to nutritional deficiencies, including bone metabolism. Several studies have reported a decrease in bone mineral density (BMD), but most of them referring to malabsorptive procedures. Restrictive procedures do not imply changes in gastrointestinal anatomy, so that one may expect fewer metabolic disturbances.

METHODS

We performed a retrospective observational study of all morbidly obese patients undergoing LSG between 2008 and 2011 at our institution. Bone densitometry was performed before surgery and 1 and 2 years after the intervention. Body size measurements, analytical variables and densitometric values in the lumbar spine (BMD, t score and z score) were investigated.

RESULTS

Forty-two patients were included, 39 females and 3 males. Mean BMI was 51.21 kg/m(2). Mean excessive BMI loss was 79.9 % after 1 year and 80.6 % after 2 years. Mean BMD values for spine increased progressively, reaching statistical significance at 1 and at 2 years. Percentage of BMD increase was 5.7 % at 1 year and 7.9 % at 2 years. An inverse correlation was observed between BMD increase and parathyroid hormone (PTH) decrease and a direct correlation between BMD and vitamin D increase.

CONCLUSION

Bone mineral density showed a progressive increase during the first and second year after sleeve gastrectomy. BMD changes are not associated with weight loss, but showed a direct correlation with vitamin D and an inverse correlation with PTH levels.

Biliopancreatic diversion: the effectiveness of duodenal switch and its limitations

The prevalence of morbidly obese individuals is rising rapidly. Being overweight predisposes patients to multiple serious medical comorbidities including type two diabetes (T2DM), hypertension, dyslipidemia, and obstructive sleep apnea. Lifestyle modifications including diet and exercise produce modest weight reduction and bariatric surgery is the only evidence-based intervention with sustainable results. Biliopancreatic diversion (BPD) produces the most significant weight loss with amelioration of many obesity-related comorbidities compared to other bariatric surgeries; however perioperative morbidity and mortality associated with this surgery are not insignificant; additionally long-term complications including undesirable gastrointestinal side effects and metabolic derangements cannot be ignored. The overall quality of evidence in the literature is low with a lack of randomized control trials, a preponderance of uncontrolled series, and small sample sizes in the studies available. Additionally, when assessing remission of comorbidities, definitions are unclear and variable. In this review we explore the pros and cons of BPD, a less well known and perhaps underutilized bariatric procedure.

Bone mineral changes in spine and proximal femur in individual obese women after laparoscopic sleeve gastrectomy: a short-term study

BACKGROUND

The aim of the study was to establish longitudinal bone changes in obese women after laparoscopic sleeve gastrectomy (LSG).

METHODS

Twenty-nine women at baseline mean age of 40.41 ± 9.26 years and with mean body mass index (BMI) of 43.07 ± 4.99 kg/m(2) were included in a 6-month study. Skeletal status at hip [femoral neck (FN) and total hip (TH)] and spine was assessed at baseline, as well as in 3 and 6 months after surgery. Body size was measured at baseline and follow-up (weight, height, BMI, and waist).

RESULTS

Baseline body weight was 117.5 ± 18.4 kg. The mean body weight and BMI decreased by 17.9 % during the first 3 months after surgery to obtain 28.4 % after 6 months. At 6 months, BMD decreased significantly for spine by 1.24 %, FN 6.99 %, and TH 5.18 %. The changes after 3 months in individual subjects showed that, in the majority of subjects, FN and TH BMD decreased significantly (in 52 % and 69 % of subjects, respectively), and in 24 % loss of BMD was found at the spine. After 6 months, the corresponding, significant decreases in individual subjects were found in 72 %, 86 %, and 38 % of woman, respectively. Those with a significant loss of FN BMD tended to lose more weight (30 ± 9.47 versus 23.25 ± 6.08 kg, p = 0.061) than others; women with a significant decrease of FN BMD lost more weight than those with no such decrease (30.43 ± 8.07 versus 15 ± 1.91 kg).

CONCLUSION

LSG proved efficient for body weight reduction, however, with a parallel decline in bone mineral density.

Nutritional deficiencies after bariatric surgery

Lifestyle intervention programmes often produce insufficient weight loss and poor weight loss maintenance. As a result, an increasing number of patients with obesity and related comorbidities undergo bariatric surgery, which includes approaches such as the adjustable gastric band or the 'divided' Roux-en-Y gastric bypass (RYGB). This Review summarizes the current knowledge on nutrient deficiencies that can develop after bariatric surgery and highlights follow-up and treatment options for bariatric surgery patients who develop a micronutrient deficiency. The major macronutrient deficiency after bariatric surgery is protein malnutrition. Deficiencies in micronutrients, which include trace elements, essential minerals, and water-soluble and fat-soluble vitamins, are common before bariatric surgery and often persist postoperatively, despite universal recommendations on multivitamin and mineral supplements. Other disorders, including small intestinal bacterial overgrowth, can promote micronutrient deficiencies, especially in patients with diabetes mellitus. Recognition of the clinical presentations of micronutrient deficiencies is important, both to enable early intervention and to minimize long-term adverse effects. A major clinical concern is the relationship between vitamin D deficiency and the development of metabolic bone diseases, such as osteoporosis or osteomalacia; metabolic bone diseases may explain the increased risk of hip fracture in patients after RYGB. Further studies are required to determine the optimal levels of nutrient supplementation and whether postoperative laboratory monitoring effectively detects nutrient deficiencies. In the absence of such data, clinicians should inquire about and treat symptoms that suggest nutrient deficiencies.

Serum bone resorption markers after parathyroidectomy for renal hyperparathyroidism: correlation analyses for the cross-linked N-telopeptide of collagen I and tartrate-resistant acid phosphatase

Patients on long-term dialysis may develop secondary hyperparathyroidism (SHPT) with increased serum concentrations of bone resorption markers such as the cross-linked N-telopeptide of type I collagen (NTX) and type-5b tartrate-resistant acid phosphatase (TRAP). When SHPT proves refractory to treatment, parathyroidectomy (PTX) may be needed. Renal patients on maintenance HD who received PTX for refractory SHPT (n = 23) or who did not develop refractory SHPT (control subjects; n = 25) were followed prospectively for 4 weeks. Serum intact parathyroid hormone (iPTH), NTX, TRAP, and bone alkaline phosphatase (BAP) concentrations were measured serially and correlation analyses were performed. iPTH values decreased rapidly and dramatically. BAP values increased progressively with peak increases observed at 2 weeks after surgery. NTX and TRAP values decreased concurrently and progressively through 4 weeks following PTX. A significant correlation between TRAP and NTX values was observed before PTX but not at 4 weeks after PTX. Additionally, the fractional changes in serum TRAP were larger than those in serum NTX at all times examined after PTX. Serum iPTH, TRAP, and NTX values declined rapidly following PTX for SHPT. Serum TRAP values declined to greater degrees than serum NTX values throughout the 4-week period following PTX.

Time-course changes in bone turnover markers and fat-soluble vitamins after obesity surgery

BACKGROUND

The available evidence indicates a progressive increase in the incidence and severity of the deficiency of certain vitamins and related clinical conditions (i.e., metabolic bone disease). Because of the potential role of fat-soluble vitamins and carotenoids in bone metabolism, our aim was to assess the time-course changes of fat-soluble vitamins and serum markers of bone metabolism in candidates for obesity surgery and following two bariatric procedures.

METHODS

Sixty-five candidates for bariatric surgery and 150 serum samples after obesity surgery (i.e., Roux-en-Y gastric bypass, n = 85; biliopancreatic diversion, n = 65) were consecutively analyzed over a period of more than 2 years. Retinol, α- and γ-tocopherol, 25-OH-vitamin D3, β-cryptoxanthin, and β-carotene were analyzed by high-performance liquid chromatography. Calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone (iPTH), osteocalcin, beta-crosslaps, and N-terminal peptide of procollagen I (P1NP) were determined using commercial kits.

RESULTS

Retinol, β-cryptoxanthin, β-carotene, and α- and γ-tocopherol levels were significantly lower in post-surgery samples while osteocalcin, b-crosslaps, and P1NP were significantly increased. Along the time and regardless of the surgical procedure, P1NP, b-crosslaps, and osteocalcin increased during the first 12-24 months but declined afterward. 25-OH-vitamin D increased during the first 12 months and tended to decrease afterward while iPTH remained constant or decreased but increased after 1 year in both groups. Vitamin A remained constant but α- and γ-tocopherol, β-cryptoxanthin, and β-carotene decreased in both groups.

CONCLUSIONS

In addition to the nutritional assessment, regular monitoring of bone markers seems necessary in these patients and the early introduction of preventive strategies (i.e., the use of antiresorptive agents) should be evaluated.

Extraskeletal effects of vitamin D: facts, uncertainties, and controversies

Vitamin D was long viewed as a hormone acting chiefly to regulate calcium-phosphate metabolism and bone mineralization. Over the last decade, however, basic science and clinical researchers have produced a bewildering amount of information on the extraskeletal effects of vitamin D. This article is a review of the clinical and biological actions of vitamin D including effects on the immune system, auto-immune diseases, infections, cancer, metabolic syndrome, fall risk, cognitive function, and muscle function.