Does Treatment of Hypovitaminosis D Increase Calcium Absorption?

July 13, 2023 updated by: University of Wisconsin, Madison
The purpose is to perform a one-year study designed to assess whether treatment of hypovitaminosis D increases intestinal absorption of calcium, subsequent retention of calcium within bone, decreases bone turnover, and favorably impacts upon skeletal muscle mass, functional status, measures of physical function and quality of life. I hypothesize that treatment of hypovitaminosis D results in improved intestinal calcium absorption, greater retention of calcium within the bone reservoir and improved physical function, quality of life and muscle mass.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Postmenopausal women with vitamin D insufficiency will participate in this one-year study. We will study the change in intestinal calcium absorption from baseline (vitamin D insufficiency) to follow up (vitamin D repletion and whether increased absorption results in subsequent increased retention of calcium within bone over the one-year interval as measured by bone densitometry. We will also study the effect of vitamin D repletion upon whole body muscle mass, quality of life and physical function.

A review of medical records and a screening visit will determine eligibility. Eligible and consenting subjects will present to the GCRC in the early morning and following baseline labs, will consume breakfast with a glass of orange juice enriched with a stable calcium isotope, and will receive 3 mg of another stable calcium isotope by intravenous injection. Over the next eight hours, blood will be taken a total of 9 more times and over the first 24 hours, all urine and stool will be collected for measurement of its calcium content.

Subsequently for the next five days, women will collect three urine specimens daily. Women will then receive vitamin D to treat vitamin D deficiency. Once vitamin D repletion is accomplished, all women will repeat their 24-hour visit and subsequent five-day urine collections. Women will maintain vitamin D repletion by taking a twice monthly tablet (50,000 IU) of vitamin D2. To confirm vitamin D repletion and safety over the full one year study, additional study visits will occur at 3, 6 and 12 months.

A bone density test at screening and twelve months will allow us to assess the effect of vitamin D repletion on whole body bone mass and skeletal mass. At each GCRC stay, 3, 6 and 12 months, women will complete questionnaires regarding quality of life and functional status and will perform the Timed Up and Go Test. Because we wish to maintain and confirm constant calcium intake throughout the one- year study, women will complete a calcium questionnaire at baseline, 3, 6 and 12 months.

With each subject's consent, we will collect one tube of blood and isolate its DNA. When sufficient knowledge is available regarding the pathophysiologic mechanisms whereby genetic polymorphisms impact calcium homeostasis, we will test for such DNA polymorphisms and relate genetic information with other data collected on calcium homeostasis.

Study Type

Interventional

Enrollment (Actual)

19

Phase

  • Phase 4

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
    • Wisconsin
      • Madison, Wisconsin, United States, 53792
        • University of Wisconsin Hospital and Clinics

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

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • women at least five years past onset of menopause, defined as date of last menses (ages reported above are the range in ages of the participants recruited to the study)
  • serum 25(OH)D 16-24 ng/ml by reverse phase HPLC
  • calcium intake < or = 1,100 mg daily

Exclusion Criteria:

  • Intake of >1,100 mg of calcium per day through the combination of diet and supplements
  • Hypercalcemia (baseline serum calcium above the normal reference range)
  • Nephrolithiasis, documented in the medical record or by patient report
  • Inflammatory bowel disease, malabsorption, chronic diarrhea, or use of antibiotics within the past month
  • Creatinine >2.0 mg/dL
  • Hypercalciuria (baseline urine calcium: creatinine ratio >0.25)
  • Current use of medications known to interfere with vitamin D and/or calcium metabolism, including oral steroids or anticonvulsants
  • Ongoing or recent (past six months) use of bisphosphonates, estrogen compounds, calcitonin or teriparatide, as these compounds may independently affect retention of calcium within bone
  • Diagnosis of, or evidence for, osteomalacia, manifest by serum 25(OH)D < 16 ng/ml or the presence of at least two of the following blood tests: low calcium, low phosphorus, or elevated alkaline phosphatase (23).
  • Prior adult clinical fragility fracture or baseline T-score below -3.0 at the lumbar spine or femur

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

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: 1
Subjects received vitamin D (50,000 IU daily for 15 days) and maintenance dose vitamin D (50,000 IU twice monthly for 10 months).
Drug: Vitamin D
50,000 IU po qd for 15 days and 50,000 IU po twice month for 10 months (until final study visit at one year)
Other Names:
  • Vitamin D2
  • Ergocalciferol

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Intestinal Calcium Absorption From Baseline to One Month
Time Frame: 1 month
percent and true fractional calcium absorption
1 month

Collaborators and Investigators

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

Sponsor

University of Wisconsin, Madison

Investigators

  • Principal Investigator: Karen E Hansen, MD, University of Wisconsin, Madison

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

January 1, 2005

Primary Completion (Actual)

July 1, 2008

Study Completion (Actual)

December 1, 2008

Study Registration Dates

First Submitted

December 19, 2007

First Submitted That Met QC Criteria

December 19, 2007

First Posted (Estimated)

December 28, 2007

Study Record Updates

Last Update Posted (Estimated)

July 24, 2023

Last Update Submitted That Met QC Criteria

July 13, 2023

Last Verified

September 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2005-0159
  • 05-1235-02

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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