Delusion of Reference Clinical Trial
Official title:
The Effects of Vitamin D and Calcium Supplementation at Tolerable Upper Limit Doses on Calcium Metabolism in Postmenopausal White Women.
Recently two distinguished committees, Institute of Medicine (IOM) and The Endocrine Society have proposed different intake guidelines for Calcium and Vitamin D. We wish to compare the effects of both of them on calcium metabolism and bone turnover. We propose a one year randomized double blinded study for the same.
The specific aims of this study proposal are to determine the following:
1. To compare the two different intake guidelines for Calcium and Vitamin D
Supplementation at its recommended tolerable upper limit on serum and urinary calcium
in white postmenopausal Women.
2. Compare the effects above mentioned two intake guidelines on Vitamin D metabolism
[25(OH)D, 1,25(OH)2D] and bone turnover.
Participants will be randomly assigned to Group A or Group B based on different dosages of
study medications.
Group A: 10,000 IU (International Units)Vitamin D + Placebo (sugar pill) 600IU Vitamin D +
Two pills Calcium containing 600mg calcium each.
Group B: 600 IU Vitamin D + Placebo (sugar pill) 10,000 IU Vitamin D
+ Two pills Calcium containing 600mg calcium each.
In addition to the calcium supplements, they will guide to include approximately 800mg of
calcium in their daily diet.
At visit 2, fasting blood and spot urine will be collected. A urinal will be dispensed for
collection of 24-hour urine for urinary calcium to be brought in next day. Study medication
will be dispensed and participants will be asked not to discard unused medications and to
bring all study medications next study visit.
Visit 3, 4, 5, 6 will essentially be the same as visit 2, with subjects returning unused
study medication and given new tablets each visit. Except on visit 6 no further study
medications will be dispensed, after collecting the previous supply.
Food frequency questionnaires will be filled out at the initial visit and final visit. Diet
will be assessed using 3-day diet history form and Nutrition Pro analysis software. Patients
will be asked to refrain from taking other Vitamin D supplements and to continue their usual
calcium intake.
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Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor), Primary Purpose: Health Services Research