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Do Aromatase Inhibitors (AIs) Decrease Intestinal Calcium Absorption?

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00766532
Recruitment Status : Completed
First Posted : October 6, 2008
Results First Posted : September 14, 2012
Last Update Posted : September 14, 2012
Information provided by (Responsible Party):
University of Wisconsin, Madison

Brief Summary:

Research Question: Do Aromatase Inhibitors Decrease Intestinal Calcium Absorption?

Study Design: Postmenopausal women with early stage breast cancer initiating aromatase inhibitor adjuvant therapy will participate in this two-month study. The primary study outcome is the change in intestinal calcium absorption following such therapy. Secondary outcomes are the changes in bone resorption markers and musculoskeletal signs and symptoms after initiation of therapy.

We will interview women and review their medical records to determine eligibility. Eligible subjects will undergo two calcium absorption studies. The first study will determine their baseline calcium absorption, and the second study will occur after taking an aromatase inhibitor daily for at least 6 weeks. Women will present to the research unit in the early morning and receive an oral and intravenous stable calcium tracer with breakfast. Over the next 24 hours, we will collect all urine for measurement of its calcium content. During each inpatient stay, we will assess musculoskeletal symptoms by questionnaire and joint examination. Each woman will complete a four-day diet diary twice during the study.

Condition or disease Intervention/treatment Phase
Breast Cancer Osteoporosis Osteopenia Fracture Drug: Aromatase Inhibitor Phase 4

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 12 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Diagnostic
Official Title: Do Aromatase Inhibitors (AIs) Decrease Intestinal Calcium Absorption?
Study Start Date : January 2009
Actual Primary Completion Date : October 2010
Actual Study Completion Date : October 2010

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Calcium

Arm Intervention/treatment
Experimental: aromatase inhibitor therapy
aromatase inhibitor therapy for six weeks
Drug: Aromatase Inhibitor
Any aromatase inhibitor started as initial adjuvant therapy

Primary Outcome Measures :
  1. Change in Intestinal Calcium Absorption Related to Aromatase Inhibitor Therapy [ Time Frame: baseline and 6 weeks later ]
    intestinal calcium absorption

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   Child, Adult, Older Adult
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Women at least 5 years past menopause, defined as date of last menses or bilateral oophorectomy
  • Newly diagnosed breast cancer and starting an AI as initial adjuvant therapy

Exclusion Criteria

  • Recent, current or planned chemotherapy for breast cancer, as this may have independent effects on intestinal health, calcium homeostasis and bone turnover
  • Allergy or intolerance to orange juice, as one isotope is given with orange juice
  • Current use of over-the-counter or prescription antacids, as they may influence Ca-Ab
  • Intestinal conditions associated with malabsorption or low gastric acid levels including Crohn's disease, ulcerative colitis, pernicious anemia, bacterial overgrowth, celiac sprue, chronic diarrhea or use of antibiotics within the past month
  • Known Stage 4 or 5 Chronic Kidney Disease, defined as an estimated GFR <30 cc/minute
  • Use of medications known to interfere with calcium or vitamin D metabolism, including oral steroids or anticonvulsants
  • Significant lymphedema precluding adequate intravenous access

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00766532

Sponsors and Collaborators
University of Wisconsin, Madison
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Principal Investigator: Karen E Hansen, MD University of Wisconsin, Madison

Publications of Results:
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Responsible Party: University of Wisconsin, Madison Identifier: NCT00766532    
Other Study ID Numbers: H-2008-0144
First Posted: October 6, 2008    Key Record Dates
Results First Posted: September 14, 2012
Last Update Posted: September 14, 2012
Last Verified: September 2012
Additional relevant MeSH terms:
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Bone Diseases, Metabolic
Bone Diseases
Musculoskeletal Diseases
Metabolic Diseases
Aromatase Inhibitors
Calcium-Regulating Hormones and Agents
Physiological Effects of Drugs
Steroid Synthesis Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action
Estrogen Antagonists
Hormone Antagonists
Hormones, Hormone Substitutes, and Hormone Antagonists