for people ages 25-70 (full criteria)
at San Francisco, California
study started
estimated completion
Principal Investigator
by Anne Schafer, MD
Photo of Anne Schafer
Anne Schafer



In this pre-post observational study, the investigators will enroll and follow a cohort of about 50 adults undergoing sleeve gastrectomy surgery for weight loss. Pre-operatively and at 6 and 12 months post-operatively, the investigators will use state-of-the-art metabolic and imaging techniques to evaluate calcium metabolism and skeletal health. Specific outcomes include intestinal calcium absorption capacity, bone mineral density (BMD) assessed by dual-energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT), and bone structure assessed by QCT and high-resolution peripheral QCT (HR-pQCT).


Calcium Metabolism Disorders Morbid Obesity sleeve gastrectomy, bariatric surgery Obesity, Morbid Metabolic Diseases


You can join if…

Open to people ages 25-70

  • Women and men 25 to 70 years old scheduled to undergo sleeve gastrectomy

Please note that the investigators are unable to provide sleeve gastrectomy; rather, potential participants must already be planning the procedure with their surgeons.

You CAN'T join if...

  • Perimenopausal women, defined as last menses >3 months but < 5 years ago
  • Known intestinal malabsorption (e.g., celiac disease, short gut syndrome, prior intestinal surgery)
  • Prior bariatric surgery
  • Use of medications known to impact bone and mineral metabolism, including use of a bisphosphonate or teriparatide in the last year or for >12 months ever; current calcitonin; prednisone >5 mg daily or the equivalent glucocorticoid for >10 days in the last 3 months; a current thiazolidinedione (TZD); an aromatase inhibitor; androgen deprivation therapy; an antiepileptic agent known to alter hepatic vitamin D clearance; or thyroid hormone replacement with current thyroid stimulating hormone < 0.1 milli-international units per liter
  • Disease known to affect bone (e.g., primary hyperparathyroidism, Pagets disease, clinically significant liver disease)
  • Illicit drug use or alcohol use >3 drinks/day
  • Serum calcium >10.2 mg/dL or calculated creatinine clearance < 30 mL/min
  • Weight >350 pounds (the maximum weight limit of the QCT scanner) at the time of the pre-operative QCT scan


  • UCSF
    San Francisco California 94143 United States

Lead Scientist at UCSF

  • Anne Schafer, MD
    Dr. Schafer is Associate Professor of Medicine and of Epidemiology & Biostatistics at UCSF and Chief of Endocrinology and Metabolism at the San Francisco VA Health Care System. She is board-certified by the American Board of Internal Medicine in the subspecialty of Endocrinology, Diabetes and Metabolism. Her research focus is osteoporosis and bone metabolism.


in progress, not accepting new patients
Start Date
Completion Date
San Francisco Veterans Affairs Medical Center
Study Type
Last Updated