Effects of Gastric Bypass Surgery and Calcium Metabolism and the Skeleton

February 27, 2019 updated by: VA Office of Research and Development

Effects of Gastric Bypass Surgery on Calcium Metabolism and the Skeleton

Obesity is a chronic illness of staggering proportions. Because weight loss through diet and exercise is difficult to attain and maintain, there has been escalating interest in bariatric surgery, including Roux-en-Y gastric bypass. Gastric bypass surgery results in long-term weight loss, dramatic improvement in comorbidities such as diabetes, and decreased mortality. Emerging evidence suggests, however, that gastric bypass may have negative effects on bone health. Because of the serious consequences of osteoporosis and fracture, this is of great concern. This study of the effects of gastric bypass on calcium metabolism and the skeleton may positively impact the clinical care of gastric bypass patients by their surgeons, primary care providers, and endocrinologists. Further, the knowledge gained may inform future investigation into the relationships between obesity, weight loss, and bone biology.

Study Overview

Status

Completed

Conditions

Study Type

Observational

Enrollment (Actual)

55

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • San Francisco, California, United States, 94121
        • San Francisco VA Medical Center, San Francisco, CA

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

25 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Men and women 25 to 70 years old scheduled to undergo gastric bypass surgery

Description

Inclusion Criteria:

Scheduled to undergo gastric bypass surgery. Please note that to be eligible, one must already be working with a bariatric surgeon and with plans in place to undergo gastric bypass. This study is unable to arrange or pay for gastric bypass surgery.

Exclusion Criteria:

  • Perimenopausal women
  • Known intestinal malabsorption
  • Prior bariatric surgery
  • Use of medications known to impact bone and mineral metabolism
  • Disease known to affect bone
  • Illicit drug use or alcohol use >3 drinks/day
  • Serum calcium >10.2 mg/dL
  • Calculated creatinine clearance <30 mL/min
  • Weight >350 pounds
  • Wrist circumference >12 inches or calf circumference >17 inches

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Gastric Bypass Surgery Patients
Obese men and women undergoing gastric bypass surgery

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Intestinal Calcium Absorption
Time Frame: 6 months (between baseline and 6 months)

Change in fractional calcium absorption, determined by dual stable isotope method.

Fractional calcium absorption is the fraction of ingested calcium that is absorbed, which is expressed here as the percentage of ingested calcium that is absorbed. The 6-month change is the mean difference in percentage absorption between time points. For example, if fractional calcium absorption were to decrease from 30% preoperatively to 25% at the 6-month postoperative time point, the change in fractional calcium absorption would be -5%.
6 months (between baseline and 6 months)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Areal Bone Mineral Density (BMD) at the Femoral Neck
Time Frame: 12 months post-operatively (between baseline and 12 months)
Areal BMD at the femoral neck by dual-energy X-ray absorptiometry (DXA). The 12-month change is the percentage change between the 12 month and baseline time points.
12 months post-operatively (between baseline and 12 months)
Trabecular Number at the Tibia
Time Frame: 12 months post-operatively (between baseline and 12 months)
Trabecular number at the tibia by high-resolution peripheral quantitative computed tomography (HR-pQCT). The 12-month change is the percentage change between the 12 month and baseline time points. HR-pQCT images were analyzed using the manufacturer's standard clinical evaluation protocol, with trabecular structure extracted using a threshold-based binarization process.
12 months post-operatively (between baseline and 12 months)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

VA Office of Research and Development

Investigators

  • Principal Investigator: Anne L Schafer, MD, San Francisco VA Medical Center, San Francisco, CA

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

July 1, 2011

Primary Completion (Actual)

April 1, 2014

Study Completion (Actual)

January 1, 2015

Study Registration Dates

First Submitted

April 5, 2011

First Submitted That Met QC Criteria

April 6, 2011

First Posted (Estimate)

April 7, 2011

Study Record Updates

Last Update Posted (Actual)

March 15, 2019

Last Update Submitted That Met QC Criteria

February 27, 2019

Last Verified

February 1, 2019

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • ENDB-007-10F
  • 1IK2CX000549-01 (U.S. NIH Grant/Contract)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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