Clinical trial NCT01593501: How Does Magnesium Status Influence Calcium Homeostasis?
Official title: How Does Magnesium Status Influence Calcium Homeostasis?
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: PHASE4
Conditions: Magnesium Deficiency
Calcium Metabolism Disorders
Keywords: vitamin D
cholecalciferol
bone mineral density
Magnesium deficiency
Calcium metabolism disorders
Lead sponsor: University of Wisconsin, Madison
Sponsor class: OTHER
Collaborators: name: National Institutes of Health (NIH)
name: National Institute on Aging (NIA)
First posted: 2012-05-08
Enrollment: 39
Sex: FEMALE
Minimum age (years): 30
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: TREATMENT

Brief summary: 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.

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

Eligibility criteria: 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

Primary outcomes:
measure: Evaluate the associations between magnesium intake, magnesium stores, fractional magnesium absorption and calcium homeostasis.
timeFrame: 0-12 months
Secondary outcomes:
measure: Does vitamin D therapy have a differential impact on calcium absorption that is dependent on magnesium stores?
timeFrame: 0-12 months
measure: Assessing relationships between magnesium status and bone mineral density.
timeFrame: 0-12 months
measure: Evaluate how magnesium status impacts the relationship between vitamin D levels and parathyroid hormone levels.
timeFrame: 0-12 months
Other outcomes:
Locations:
city: Madison
country: United States
facility: University of Wisconsin-Madison Hospital, Clinical Research Unit, Osteoporosis Research Center
state: Wisconsin
Study officials:
affiliation: University of Wisconsin-Madison, Department of Medicine, Division of Rheumatology
name: Karen E Hansen, M.D., M.S.
role: PRINCIPAL_INVESTIGATOR
References:
citation: Hansen KE, Nabak AC, Johnson RE, Marvdashti S, Keuler NS, Shafer MM, Abrams SA. Isotope concentrations from 24-h urine and 3-h serum samples can be used to measure intestinal magnesium absorption in postmenopausal women. J Nutr. 2014 Apr;144(4):533-7. doi: 10.3945/jn.113.186767. Epub 2014 Feb 5.