Mineral Metabolism and Bone Disease after Bariatric Surgery and Ways to Optimize Bone Health

Adequate vitamin D supplementation does not ameliorate bone loss following long limb-biliopancreatic diversion in morbidly obese women

OBJECTIVES

The objective of this study is to investigate the effect of adequate vitamin D supplementation on bone mineral density (BMD) following long limb-biliopancreatic diversion (LL-BPD), a malabsorptive bariatric operation.

BACKGROUND

Marked weight loss following bariatric surgery is associated with significant decrease in BMD, attributed to the weight loss and to nutritional, mineral, and vitamin D deficiencies resulting in secondary hyperparathyroidism.

METHODS

Two groups, of 35 and 37 healthy, obese (BMI, 50.4 + 6.6 and 46.5 + 4.8 g/cm²), premenopausal, normally menstruating women underwent LL-BPD. Both groups received high-calcium diets, 600 IU of vitamin D, and 1000 mg elemental calcium daily, while group B received an extra dose of vitamin D (10,000 IU/day) during the first postoperative month, followed by dose adjustment in order to maintain 25OHD concentration higher than 30 μg/L. Areal BMD (aBMD) was measured at the lumbar spine preoperatively and 1 year postoperatively.

RESULTS

One year postoperatively, BMI decreased by approximately 19 kg/m² in both groups, while 25-OH-vitamin D levels did not change in group A (18.7 + 9.1 to 20.2 + 13.0 μg/L, (p = 0.57)) and increased in group B (15.58 ± 5.73 to 52.97 ± 15.46 μg/L, (p = < 0.001). PTH levels increased in group A (from 38.5 ± 12.2 to 51.2 ± 32.8 pg/ml) (p = 0.047) and decreased in group B (from 51.61 ± 18.7 to 45.1 ± 17.8 pg/ml) (p = 0.042). Lumbar spine aBMD decreased similarly in both groups (p = 0.311, for the comparison between groups) from 1.198 + 0.14 to 1.103 + 0.15 g/cm² in group A (p < 0.001) and from 1.157 + 0.14 to 1.076 + 0.14 g/cm² in group B (p < 0.001) and Z-score from 0.93 + 0.97 to 0.19 + 1.02, (p < 0.001) and from 1.15 + 1.29 to 0.419 + 1.28, (p < 0.001), respectively.

CONCLUSIONS

LL-BPD leads to similar and significant bone mass reduction 1 year postoperatively, irrespective of adequate vitamin D replacement and in the absence of secondary hyperparathyroidism.

The Effect of a Muscle Weight-Bearing and Aerobic Exercise Program on the Body Composition, Muscular Strength, Biochemical Markers, and Bone Mass of Obese Patients Who Have Undergone Gastric Bypass Surgery

BACKGROUND

The effect of an exercise program on the body composition, muscular strength (MS), biochemical markers, and bone mineral density (BMD) of individuals undergoing gastric bypass is unclear. We assessed lean mass (LM), MS, bone remodeling markers, and BMD before and after supervised weight-bearing and aerobic exercise training in obese patients who underwent Roux-en-Y gastric bypass (RYGB).

METHODS

This study included 37 obese patients (81.1% women, mean age 38.2 years, mean body mass index 42.4 ± 0.5 kg/m²). Whole body densitometry was used to evaluate pre- and postoperative BMD, total body fat, and LM. Serum calcium, parathyroid hormone, 25-hydroxyvitamin D, and bone remodeling markers were measured. MS was determined through the concentric 10 repetition maximum test. Postoperatively, participants were divided into two groups: the training group, who followed an exercise program (TG, n = 18), and the control group, who did not (CG, n = 19).

RESULTS

After 1 year, the TG showed a lower decrease in total BMD and at the lumbar spine and right hip compared with the CG (p < 0.001). The TG had lower mass reduction and an increase in upper limb LM compared with the CG (both p < 0.05). There was no significant difference between groups in bone markers or calcium metabolism. MS was higher in the TG than the CG (p < 0.05).

CONCLUSION

The supervised exercise program attenuated lumbar spine and right hip BMD loss and improved LM in the arms and overall MS but did not affect bone remodeling.

Loose and frequent stools and PTH levels are positively correlated post-gastric bypass surgery due to less efficient intestinal calcium absorption

BACKGROUND

After Roux-en-Y gastric bypass, calcium and vitamin D deficiencies are frequently reported. In the presence of adequate vitamin D levels, calcium deficiency is caused by a lower efficacy of the intestinal calcium transport.

OBJECTIVE

To investigate whether the use of a simple clinical score quantifying bowel habits (fecal score [FS]) correlates with the degree of secondary hyperparathyroidism that arises to compensate for calcium deficiency postsurgery.

SETTING

Large peripheral hospital.

METHODS

Seventy-five patients supplemented with calcium and vitamin D were prospectively studied before and 6 and 12 months after Roux-en-Y gastric bypass. FS, calcium (mmol/L), phosphate (mmol/L), magnesium (mmol/L), vitamin D (nmol/L), and parathyroid hormone (PTH; pmol/L) were measured in each patient.

RESULTS

Mean body mass index was 44.7±5.4 kg/m² preoperatively and decreased to 34.3±5.0 kg/m² at 6 months and 30.8±4.8 kg/m² at 12 months, corresponding to a total weight loss of 23.2±5.9% and 30.9±8.3% respectively. There were no significant changes in serum calcium levels. Mean PTH levels rose from 3.5 pmol/L at baseline to 4.1 pmol/L at 6 months (P = .01) and to 4.9 pmol/L at 12 months (P<.001). Nine patients (12%) had increased PTH levels at 6 months, and 14 patients (19%) had increased PTH levels at 12 months. A significant positive correlation between FS and PTH at 12 months was found, which persisted after adjusting for vitamin D levels.

CONCLUSION

FS is positively correlated with secondary hyperparathyroidism using vitamin D-adjusted PTH levels as a biochemical marker. The present study in humans confirms the relation reported in animal studies. These results emphasize that managing stool habits are important after bariatric surgery.

Vitamin and Mineral Deficiencies After Biliopancreatic Diversion and Biliopancreatic Diversion with Duodenal Switch--the Rule Rather than the Exception

INTRODUCTION

Malabsorptive bariatric procedures, like the biliopancreatic diversion (BPD) and BPD with duodenal switch (BPD/DS), have excellent results in terms of weight loss. However, these malabsorptive techniques are associated with severe malnutrition and vitamin deficiencies. The aim of this study was to evaluate the vitamin and mineral status after BPD and BPD/DS in the long term.

METHODS

All patients who underwent BPD or BPD/DS were selected and invited for an additional follow-up (FU) visit, including blood sampling for vitamin and mineral levels.

RESULTS

Forty patients completed the blood sampling with a median FU of 42 (range 12-90) months. At that time, all patients used some kind of supplementation. However, 93 % of all patients were diagnosed with a deficiency. There were no significant differences in mean serum level vitamins and minerals between BPD and BPD/DS. Forty-three per cent of the patients were anaemic, and 40 % had an iron deficiency (ID). High deficiency rates for fat-soluble vitamins were present: vitamin A in 28 %, vitamin D in 60 %, vitamin E in 10 % and vitamin K in 60 % of the patients. Hypervitaminosis was found in 43 % of the patients for vitamin B1 and in 50 % for vitamin B6.

CONCLUSION

High numbers of vitamin and mineral deficiencies were found after BPD and BPD/DS despite vitamin supplementation. Anaemia, ID and deficiencies for fat-soluble vitamins are frequently diagnosed. Repeated monitoring is necessary to detect deficiencies at an early stage. Taking all of this into consideration, a stringent multivitamin supplementation regimen should be implemented after malabsorptive procedures.

Effect of weight loss on bone mineral density determined by ultrasound of phalanges in obese women after Roux-en-y gastric bypass: conflicting results with dual-energy X-ray absorptiometry

The rapid weight loss that occurs in obese patients submitted to Roux-en-y gastric bypass (RYGB) as well as the changes in dietary pattern and the intestinal malabsorption result in changes in bone mineral density (BMD). The objective of the present study was to assess the changes in BMD after the weight loss induced by RYGB using ultrasound of the phalanges and compare the results with those obtained by dual-energy X-ray absorptiometry (DXA). We conducted a 1-yr prospective longitudinal study on women with grade III obesity submitted to RYGB. Anthropometric (weight, height, body mass index, and abdominal circumference) and body composition measurements by electrical bioimpedance, assessment of food consumption by 24-h recall, biochemical evaluation, and assessment of BMD by ultrasonography of the phalanges and DXA (BMD values are from the 33% radius site) were performed during the preoperative period and 3, 6, and 12 mo after surgery. The mixed-effects linear regression model was used to analyze the effect of postoperative time on the variable of interest, and the kappa coefficient (p < 0.05) was used to compare the concordance of the methods used for BMD evaluation. Twenty-nine patients were included in the study. During the 1-yr follow-up, a reduction of 39 ± 8 kg (71 ± 15% of excess weight) and 29 ± 7 kg of fat mass was observed. Calcium and zinc concentrations were reduced after 12 mo. No difference in caffeine, calcium, or sodium consumption was observed between the preoperative and postoperative periods. Analysis of BMD by ultrasonography of the phalanges 1 yr after surgery showed increased values of amplitude-dependent speed of sound (2064.6 ± 59.4 vs 2154.7 ± 63 m/s; p < 0.001) and ultrasound bone profile index (0.73 ± 0.13 vs 0.76 ± 0.14; p < 0.001). Analysis of BMD by DXA showed a reduction of BMD values (0.6 ± 0.04 vs 0.57 ± 0.05 g/cm³; p < 0.001) in the sixth month and maintenance of the values from the sixth to the 12th month. At the end of the study, there was no concordance between the methods for BMD analysis. This study showed improvement in bone quality and quantity assessed by ultrasonography. However, the DXA results showed a reduction in BMD after 12 mo of RYGB. Thus, the BMD measurement methods were discordant.

Bone mineral density after bariatric surgery. A systematic review

PURPOSE

Bone regulation system may be affected after bariatric surgeries, but procedures impact differently to bone mineral density (BMD) and measures restraining bone loss are frequently neglected until clinical consequences become manifest. This is a systematic review aimed to elucidate whether BMD loss is comparable after different bariatric surgeries.

MATERIALS AND METHODS

A search of morbid obese adults, undergone to bariatric surgery, with BMD measured by dual-energy X-ray absorptiometry at baseline and after surgery studies was performed in several databases. Studies were assessed using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement and COCHRANE Risk of Bias tool. The random model was selected for meta-analysis; heterogeneity was analyzed with T(2), inconsistency (I(2) > 50%) and Chi(2) (p < 0.10). Level of evidence and strength of recommendations were summarized using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE System).

RESULTS

Twelve studies met the selection criteria. After one year, reduction in total BMD in patients with mixed surgical procedures was significant: -0.03 g/cm(2) (CI 95% 0.00 to -0.06, p < 0.05). BMD was reduced by -0.12 g/cm(2) (CI 95% -0.10 to -0.15, p < 0.001) in the hip, -0.07 g/cm(2) (CI 95% -0.03 to -0.11, p < 0.001) in the column, and -0.03 g/cm(2) (IC 95% -0.02 to -0.04, p < 0.001) in the forearm, but not in restrictive surgeries. Studies included showed high heterogeneity and low quality of evidence.

CONCLUSIONS

Patients undergone to mixed bariatric surgery had significant higher BMD deterioration as demonstrated in this review, suggesting that more attention for preventing fractures is required.

Early and long-term clinical outcomes of bilio-intestinal diversion in morbidly obese patients

PURPOSE

To evaluate the early and long-term postoperative results of malabsorptive surgery in morbidly obese patients.

METHODS

Between 2000 and 2007, 102 morbidly obese patients were referred to the Department of Surgery "Pietro Valdoni", "Sapienza" University of Rome, Policlinico "Umberto I°", Rome, Italy for malabsorptive surgery. All patients underwent derivative biliodigestive surgery after they had been reviewed by a team of surgeons, physicians, dieticians, and psychologists.

RESULTS

There were no intra-operative complications, but two patients suffered postoperative pulmonary embolisms, which resolved with medical treatment. The mean postoperative hospital stay was 7 days, with no early or late mortality. Maximum weight loss was reached 12-24 months after surgery, while the mean percentage excess weight loss at 3-5 years ranged from 45 to 64 %. Specific postoperative complications in the first 2 years after surgery were abdominal abscess (n = 2), gastroduodenal reflux (n = 4), and incisional hernia (n = 6). Diabetes resolved in 98 % of the diabetic patients within a few weeks after surgery and blood pressure normalised in 86.4 % of those who had had hypertension preoperatively. Obstructive sleep apnoea and obesity hypoventilation syndrome also improved significantly in 92 % of the patients.

CONCLUSIONS

Morbidly obese patients can undergo biliodigestive surgery safely with good long-term weight loss and quality of life expectancy.

Update on micronutrients in bariatric surgery

PURPOSE OF REVIEW

Obesity is a growing worldwide epidemic. Obese patients are often deficient in micronutrients despite macronutrient excess. Bariatric surgery is an increasingly utilized modality in the treatment of obesity and obesity-related conditions. Bariatric surgery itself may cause or exacerbate micronutrient deficiencies with serious sequelae. This review will focus on perioperative strategies to detect, prevent and treat micronutrient deficiencies in patients undergoing bariatric surgery, and will highlight practical and clinical aspects of these nutritional problems.

RECENT FINDINGS

Micronutrient deficiency is common in obese patients undergoing bariatric surgery both preoperatively and postoperatively. Bariatric procedures with a malabsorptive component are more likely to result in postoperative micronutrient deficiency. A system-based approach will facilitate clinical suspicion of specific or combined micronutrient deficiencies, leading to appropriate laboratory tests for confirmation. Supplementation by the oral route is always tried first, reserving parenteral administration for specific situations.

SUMMARY

Clinicians should be aware that micronutrient deficiencies are common in obese patients who may have macronutrient excess. Micronutrient deficiency may exist preoperatively or be caused by bariatric procedures themselves. A systematic and team-based approach will decrease morbidity associated with delays in diagnosis and treatment.

The gastric sleeve: losing weight as fast as micronutrients?

Background

Recently, the laparoscopic sleeve gastrectomy (LSG) has become popular as a single-stage procedure for the treatment of morbid obesity and its co-morbidities. However, the incidence of micronutrient deficiencies after LSG have hardly been researched.

Methods

From January 2005 to October 2008, 60 patients underwent LSG. All patients were instructed to take daily vitamin supplements. Patients were tested for micronutrient deficiencies 6 and 12 months after surgery.

Results

Anemia was diagnosed in 14 (26%) patients. Iron, folic acid, and vitamin B12 deficiency was found in 23 (43%), eight (15%), and five (9%) patients, respectively. Vitamin D and albumin deficiency was diagnosed in 21 (39%) and eight (15%) patients. Hypervitaminosis A, B1, and B6 were diagnosed in 26 (48%), 17 (31%), and 13 (30%) patients, respectively.

Conclusions

Due to inadequate intake and uptake of micronutrients, patients who underwent LSG are at serious risk for developing micronutrient deficiencies. Moreover, some vitamins seem to increase to chronic elevated levels with possible complications in the long-term. Multivitamins and calcium tablets should be regarded only as a minimum and supplements especially for iron, vitamin B12, vitamin D, and calcium should be added to this regimen based on regular blood testing.

Semiquantitative assessment of bowel habits and its relation with calcium metabolism after gastric bypass surgery: a retrospective study

Background. Calcium malabsorption after bariatric surgery may be harmful to skeletal health and demands for optimal skeletal management. Methods. 103 Patients were evaluated retrospectively at 12 months after surgery. The evaluation included a questionnaire about stool frequency and consistency and laboratory assessments. Results. 103 Patients, 27 males and 76 females, were included in the study. 83 Patients had an alimentary limb of 100 cm and 20 patients one of 150 cm. At 12 months after surgery, 77.7% reported changes of bowel habits, albumin adjusted calcium levels were normal in all but 2 patients, and PTH levels were increased in 35%. Correlations between semiquantified bowel scores (fecal scores) and data from the laboratory demonstrated increasing PTH values along with more frequent and softer/watery stools (RR 30.5, CI 6.2-149.2, P < .001). There was a trend for higher PTH levels in patients with an alimentary limb of 150 cm. Normal PTH levels were more frequently found in case of calcium and vitamin D3 use (RR 14.3, CI 3.6-56.5, P < .001). Conclusion. This study demonstrates interrelationships between semi-quantified fecal scores, PTH levels, and the compliance of taking calcium/vitamin D3 suppletion. However, prospective randomized studies are necessary to show causal relationships.

Endocrine and nutritional management of the post-bariatric surgery patient: an Endocrine Society Clinical Practice Guideline

OBJECTIVE

We sought to provide guidelines for the nutritional and endocrine management of adults after bariatric surgery, including those with diabetes mellitus. The focus is on the immediate postoperative period and long-term management to prevent complications, weight regain, and progression of obesity-associated comorbidities. The treatment of specific disorders is only summarized.

PARTICIPANTS

The Task Force was composed of a chair, five additional experts, a methodologist, and a medical writer. It received no corporate funding or remuneration.

CONCLUSIONS

Bariatric surgery is not a guarantee of successful weight loss and maintenance. Increasingly, patients regain weight, especially those undergoing restrictive surgeries such as laparoscopic banding rather than malabsorptive surgeries such as Roux-en-Y bypass. Active nutritional patient education and clinical management to prevent and detect nutritional deficiencies are recommended for all patients undergoing bariatric surgery. Management of potential nutritional deficiencies is particularly important for patients undergoing malabsorptive procedures, and strategies should be employed to compensate for food intolerance in patients who have had a malabsorptive procedure to reduce the risk for clinically important nutritional deficiencies. To enhance the transition to life after bariatric surgery and to prevent weight regain and nutritional complications, all patients should receive care from a multidisciplinary team including an experienced primary care physician, endocrinologist, or gastroenterologist and consider enrolling postoperatively in a comprehensive program for nutrition and lifestyle management. Future research should address the effectiveness of intensive postoperative nutritional and endocrine care in reducing morbidity and mortality from obesity-associated chronic diseases.

Micronutrient deficiencies after bariatric surgery

It has been estimated that approximately 220,000 people with morbid obesity underwent bariatric surgery in 2008. Modification of the gastrointestinal tract affects absorption and health care professionals counseling bariatric patients need to be aware of possible micronutrient deficiencies and their symptoms. A systematic review of several databases and bariatric surgery center websites on the Internet was conducted from January 1980 to July 2009 to identify literature related to micronutrient deficiencies occurring after bariatric surgery. Keywords used individually or in combination were bariatric surgery, obesity, vitamin/mineral deficiencies, altered gastrointestinal function, nutrient absorption, nutrient supplementation, and metabolic complications, and were variously combined in the search list. Based on this review, all patients scheduled for bariatric surgery should receive daily multivitamin and multitrace mineral supplements. The literature suggests that bariatric surgery patients are at risk for deficiency of the following nutrients after surgery: vitamins B(12), B(1), C, folate, A, D, and K, along with the trace minerals iron, selenium, zinc, and copper. Over-the-counter multivitamin and mineral supplements do not provide adequate amounts of certain nutrients such as vitamin B(12), iron, or fat-soluble vitamins and patients will require additional doses of prophylactic supplementation life-long to maintain optimal micronutrient status. In addition, preconception care for adequate prenatal supplementation is critical for pregnant women who have undergone bariatric surgery, as iron, vitamin A, vitamin B(12), vitamin K, and folate deficiencies are associated with maternal and fetal complications, including severe anemia, congenital abnormalities, low birth weight, and failure to thrive. All bariatric surgery patients would be best served by receiving regular monitoring of serum nutrient levels starting at 3 mo after surgery and periodically thereafter.

Bariatric surgery and bone metabolism: a systematic review

Few studies have demonstrated the risk of metabolic bone disease and a reduction in bone mineral density (BMD) after bariatric surgery. A systematic review was conducted of case-control and cohort studies with the aim of evaluating the relationship between bariatric surgery and bone metabolism. The search was undertaken in MedLine, covering the period from January 1997 to August 2009, using the keywords: "bariatric surgery" AND "osteoporosis", "fracture", "bone diseases", "metabolic". Six studies were included, comprising four cohort and two case-control studies. Three studies evaluated bone metabolism and BMD, and the other evaluated bone metabolism only. Based on this review, bariatric surgery is associated with alterations in bone metabolism, loss of bone mass and an increased risk of fracture. However, the maximum evaluation period covered by these studies was two years after surgery, hence the need to undertake further studies of longer duration in order to achieve a more thorough understanding of this association.

Recommended nutritional supplements for bariatric surgery patients

OBJECTIVE

To review nutritional supplements commonly required after bariatric surgery to provide a practical guide and reference source for generalist healthcare providers.

DATA SOURCES

A PubMed literature search (1988-July 2008) was conducted, using the search term nutritional deficiency after bariatric surgery, and was limited to English-language literature on adult (aged >19 y) human subjects. Additional references from the selected literature were also included.

STUDY SELECTION AND DATA EXTRACTION

Data were extracted from large clinical series and practice guidelines whenever possible. Case reports were used only when they were the sole information source.

DATA SYNTHESIS

Nutritional deficiencies that occur after bariatric surgery depend significantly on the type of surgery performed. Restrictive procedures such as gastric banding are the least likely to cause nutritional deficits, since none of the intestine is bypassed. Malabsorptive procedures such as biliopancreatic diversion or mixed restrictive/malabsorptive procedures (eg, Roux-en-Y gastric bypass) can result in serious nutritional problems when patients do not take required supplements after surgery. Vitamins and minerals that are commonly deficient in this circumstance include vitamin B(12), calcium, vitamin D, thiamine, folic acid, iron, zinc, and magnesium. Rare ocular complications have been reported with hypovitaminosis A.

CONCLUSIONS

Healthcare professionals, especially those who practice outside large bariatric centers, must be aware of the supplements required by patients who have had bariatric surgery. Many patients fail to follow up with the surgery centers and are managed by their primary care teams and community pharmacists, especially in the selection of multivitamin and nutritional supplements.

The bone-adipose axis in obesity and weight loss

Body fat and lean mass are correlated with bone mineral density, with obesity apparently exerting protection against osteoporosis. The pathophysiological relevance of adipose tissue in bone integrity resides in the participation of adipokines in bone remodeling through effects on deposition and resorption. On the other hand, the skeleton has recently emerged as an endocrine organ with effects on body weight control and glucose homeostasis through the actions of bone-derived factors such as osteocalcin and osteopontin. The cross-talk between adipose tissue and the skeleton constitutes a homeostatic feedback system with adipokines and molecules secreted by osteoblasts and osteoclasts representing the links of an active bone-adipose axis. Given the impact of bariatric surgery on absorption and the adipokine secretory pattern, to focus on the changes taking place following surgical-induced weight loss on this dynamic system merits detailed consideration.