Bone Metabolism After Laparoscopic Gastric Bypass Surgery (BABS)

Study Overview
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Brief Summary
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Bariatric surgery leads to rapid weight loss in female and male patients. Less data are available about its impact on bone metabolism. The aim of this study is the investigation of changes in bone mineral density,bone histomorphometric changes, serum bone turnover markers and changes in body fat and muscle composition in patients after laparoscopic gastric bypass surgery.

Detailed Description
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Obese female and male adult patients eligible for laparoscopic gastric bypass surgery according to the national Austrian guidelines will be included in this study upon request and after patient approval. Baseline data collection and quarterly follow up visits are planned to investigate the changes in bone mineral density and body composition measured by dual energy X-ray absorptiometry as well as the evaluation of serum bone turnover markers of bone formation and resorption. After surgery subjects will be randomized into two groups: Daily oral calcium (500mg) and weekly vitamin D3 supplementation (16.000 IU calciferol)or no supplementation of calcium and calciferol. A sub-study (approximately 15% of study population) with transiliac bone biopsies will also be performed to investigate histomorphometric and histologic changes in bone (biopsy baseline and after 24 months). The planned duration of the study is 24 months for each subject. Serum bone turnover markers will be collected every 3 months, dual energy X-ray absorptiometry measurements will be performed every 6 months.

Official Title
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Phase 2 Study of Patients Undergoing Bariatric Surgery (Laparoscopic Gastric Bypass) and Evaluation of Bone Metabolism With/Without Vitamin D/Calcium Supplementation

Conditions
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Evaluation of Expected Bone Loss After Bariatric Surgery, Possible Prevention of Bone Loss After Surgery by Calcium and Vitamin D Supplementation

Intervention / Treatment
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* Drug: Calciferol, calcium carbonate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: body mass index >35 female and male patients age 18 - 65 years eligible for laparoscopic gastric bypass surgery according to the Austrian national guidelines Exclusion Criteria: any history of malignancy except basalioma any prior antiresorptive treatment any prior calcium or vitamin D supplementation any secondary disease affecting bone metabolism

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Calcium/Vitamin D<br>All subjects will receive calcium/vitamin D supplementation after laparoscopic bariatric gastric bypass surgery as follows: daily: 500 mg oral calcium (calcium carbonate) weekly: 16.000 IU oral vitamin D3 (calciferol) | Drug: Calciferol, calcium carbonate<br> <br> |
| No Intervention: No Calcium/Vitamin D<br>All subjects will not receive calcium/vitamin D supplementation after laparoscopic bariatric gastric bypass surgery. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluation of bone mineral density changes in obese patients after laparoscopic bariatric surgery | Dual energy X-ray absorptiometry (DXA) measurements of bone mineral density at lumbar spine, hip, calcaneus and total body will be performed at baseline and every six months for a period of 24 months. Differences will be evaluated on the outcome with/without daily calcium (500mg) and weekly vitamin D (16.000 IU calciferol) supplementation | Evaluation every 6 months for 24 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluation of changes of serum bone turnover markers in obese patients after laparoscopic bariatric surgery | Fasting serum markers of bone formation and bone resorption will be evaluated: Calcium, 25-OH-vitamin D3, intact parathyroid hormone, beta-crosslaps, type-1-procollagen, bone specific alkaline phosphatase, osteocalcin, sclerostin, osteoprotegerin, cathepsin-K, fibroblast factor 23, lipoprotein A, dickkopf 1 Differences will be evaluated on the outcome with/without daily calcium (500mg) and weekly vitamin D (16.000 IU calciferol) supplementation | Evaluation every 3 months for 24 months |