Effects of Gastric Bypass Surgery and Calcium Metabolism and the Skeleton
This study has been completed.
Information provided by (Responsible Party):
VA Office of Research and Development
First received: April 5, 2011
Last updated: April 12, 2016
Last verified: April 2016
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.
||Observational Model: Cohort
Time Perspective: Prospective
||Effects of Gastric Bypass Surgery on Calcium Metabolism and the Skeleton
Primary Outcome Measures:
- Change in Intestinal Calcium Absorption [ Time Frame: 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%.
Biospecimen Retention: Samples Without DNA
Secondary Outcome Measures:
- Bone Mineral Density (BMD, Areal and Volumetric) [ Time Frame: pre-operatively and 6 and 12 months post-operatively ]
Areal BMD at the spine, proximal femur, and forearm by dual-energy X-ray absorptiometry (DXA); volumetric BMD at the spine and hip by quantitative computed tomography (QCT); volumetric BMD at the ultradistal radius and ultradistal tibia by high-resolution peripheral QCT (HR-pQCT)
- Bone Structure [ Time Frame: pre-operatively and 6 and 12 months post-operatively ]
Trabecular and cortical bone microstructure by HR-pQCT
| Study Start Date:
| Study Completion Date:
| Primary Completion Date:
||April 2014 (Final data collection date for primary outcome measure)
Gastric Bypass Surgery Patients
Obese men and women undergoing gastric bypass surgery
|Ages Eligible for Study:
||25 Years to 70 Years (Adult, Senior)
|Sexes Eligible for Study:
|Accepts Healthy Volunteers:
Men and women 25 to 70 years old scheduled to undergo gastric bypass surgery
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.
- 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
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To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.
Please refer to this study by its ClinicalTrials.gov identifier: NCT01330914
|San Francisco VA Medical Center, San Francisco, CA
|San Francisco, California, United States, 94121 |
VA Office of Research and Development
||Anne L Schafer, MD
||San Francisco VA Medical Center, San Francisco, CA
Schafer AL, Weaver CM, Black DM, Wheeler AL, Chang H, Szefc GV, Stewart L, Rogers SJ, Carter JT, Posselt AM, Shoback DM, Sellmeyer DE. Intestinal Calcium Absorption Decreases Dramatically After Gastric Bypass Surgery Despite Optimization of Vitamin D Status. J Bone Miner Res. 2015 Aug;30(8):1377-85. doi: 10.1002/jbmr.2467.
Schafer AL, Li X, Schwartz AV, Tufts LS, Wheeler AL, Grunfeld C, Stewart L, Rogers SJ, Carter JT, Posselt AM, Black DM, Shoback DM. Changes in vertebral bone marrow fat and bone mass after gastric bypass surgery: A pilot study. Bone. 2015 May;74:140-5. doi: 10.1016/j.bone.2015.01.010.
||VA Office of Research and Development
History of Changes
|Other Study ID Numbers:
|Study First Received:
||April 5, 2011
|Results First Received:
||December 2, 2015
||April 12, 2016
Keywords provided by VA Office of Research and Development:
Calcium Metabolism Disorders
Additional relevant MeSH terms:
ClinicalTrials.gov processed this record on February 28, 2017
Signs and Symptoms
Bone Density Conservation Agents
Physiological Effects of Drugs