How Does Magnesium Status Influence Calcium Homeostasis?

October 31, 2016 updated by: University of Wisconsin, Madison
The investigators aim to recruit 60 women who have agreed to participate in an existing randomized, double-blind, placebo-controlled trial (Treatment of Vitamin D Insufficiency, HSC 2009-0055). In this trial, the investigators propose to evaluate the associations between magnesium intake, magnesium stores, fractional magnesium absorption and calcium homeostasis. The investigators will stratify 60 subjects in the sub-study, ensuring that approximately 20 subjects are randomized into each treatment arm (placebo, low-dose and high-dose vitamin D). The investigators already assess calcium homeostasis throughout the study by measuring bone mineral density, fractional calcium absorption, serum and urine calcium levels, among other tests. In the sub-study of 60 women, the investigators will evaluate whether habitually higher magnesium intake increases or decreases fractional calcium absorption. The investigators will evaluate the interplay between magnesium stores, vitamin D levels and serum parathyroid hormone levels. The investigators will directly assess magnesium stores using serum magnesium and 24-hour urine magnesium levels, and will measure magnesium absorption using the dual stable isotope approach.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Use of serum magnesium isotopes to measure fractional magnesium absorption Four day food diaries to assess magnesium intake Standard urine and serum chemistries for remaining labs as noted above

Study Type

Interventional

Enrollment (Actual)

39

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, 53705
        • University of Wisconsin-Madison Hospital, Clinical Research Unit, Osteoporosis Research Center

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

30 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • participants eligible for the study "Treatment of vitamin D insufficiency" are eligible for participation in the current sub-study

Exclusion Criteria:

  • identical to those covered in HSC #2009-0055

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: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Active Comparator: High dose vitamin D
50,000 IU vitamin D3 every 15 days, with a loading dose of 50,000 IU per day for the first 15 days of an approximate 365-day treatment.
Dietary supplement: vitamin D3
pharmaceutical grade D3
Other Names:
  • Cholecalciferol
Active Comparator: Low dose vitamin D
800 IU vitamin D3 every day of an approximate 365-day treatment.
Dietary supplement: vitamin D3
pharmaceutical grade D3
Other Names:
  • Cholecalciferol
Placebo Comparator: Placebo
A pill that looks like the low/high dose vitamin D pills, but contains no vitamin D. Given to preserve the double-blind nature of the study.
Dietary supplement: vitamin D3
pharmaceutical grade D3
Other Names:
  • Cholecalciferol

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Evaluate the associations between magnesium intake, magnesium stores, fractional magnesium absorption and calcium homeostasis.
Time Frame: 0-12 months
To evaluate relationships between magnesium intake and fractional magnesium absorption at baseline and 12 months, among 60 women participating in HSC Protocol 2009-0055, and to assess whether vitamin D therapy influences magnesium absorption among these women. We will also evaluate whether data collected from less than 72 hours of urine following tracer administration permits accurate assessment of fractional magnesium absorption.
0-12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Does vitamin D therapy have a differential impact on calcium absorption that is dependent on magnesium stores?
Time Frame: 0-12 months
To assess whether vitamin D therapy has a differential impact on calcium absorption, depending on magnesium stores. We will use data from all subjects participating in HSC Protocol 2009-0055 to evaluate whether magnesium status is a co-factor in the change in calcium absorption that occurs with vitamin D therapy.
0-12 months
Assessing relationships between magnesium status and bone mineral density.
Time Frame: 0-12 months
0-12 months
Evaluate how magnesium status impacts the relationship between vitamin D levels and parathyroid hormone levels.
Time Frame: 0-12 months
0-12 months

Collaborators and Investigators

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

Sponsor

University of Wisconsin, Madison

Collaborators

National Institutes of Health (NIH)
National Institute on Aging (NIA)

Investigators

  • Principal Investigator: Karen E Hansen, M.D., M.S., University of Wisconsin-Madison, Department of Medicine, Division of Rheumatology

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

May 1, 2012

Primary Completion (Actual)

August 1, 2013

Study Completion (Actual)

August 1, 2014

Study Registration Dates

First Submitted

May 4, 2012

First Submitted That Met QC Criteria

May 7, 2012

First Posted (Estimate)

May 8, 2012

Study Record Updates

Last Update Posted (Estimate)

November 1, 2016

Last Update Submitted That Met QC Criteria

October 31, 2016

Last Verified

October 1, 2016

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HSC #2011-0547
  • R01AG028739-01A2 (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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