Using Ca-41 Methodology to Assess the Impact of Different Vitamin D Supplementation Levels on Postmenopausal Bone Health

Study Overview
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Brief Summary
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The purpose of this study is to determine whether increasing levels of serum 25(OH)Vitamin D as achieved by oral supplementation higher than the current recommendations are associated with a less negative bone calcium balance in post-menopausal Swiss women.

Detailed Description
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In a substudy - not related to the vitamin D intervention - spot and 24 h urine samples are compared with regard to the assessment of iodine status in Swiss post-menopausal women. In an short subsequent study using five of the subjects who participated in the original trial, the effect of a 40 d-exercise program (rebounding on a trampoline) on Ca-41 excretion will be observed.

Official Title
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Using Ca-41 Methodology to Assess the Impact of Different Vitamin D Supplementation Levels on Postmenopausal Bone Health

Conditions
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Osteopenia

Intervention / Treatment
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* Dietary Supplement: vitamin D
* Behavioral: exercise program (rebounding on a trampoline)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: apparently healthy women, at least 5 years post-menopausal BMI 18-30 no HRT no regular intake of Ca or vit D supplements wiling and able to give written informed consent and to understand, participate and comply with study requirements non-smokers no long travels (>3 wk) planned within study period Exclusion Criteria: diseases that predispose to osteoporosis history of fragility fractures currently on a weight reduction program excessive physical activity diseases influencing calcium metabolism (thyroid, parathyroid, adrenal disorders etc.) regular intake of medication affecting calcium metabolism osteoporosis (T-score below -2.5) history of psychological illness likely to interfere with the subject's ability to understand the requirements of the study participation in concurrent studies

Ages Eligible for Study
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Minimum Age: 55 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Vitamin D<br>Vitamin D supplement | Dietary Supplement: vitamin D<br>* Vitamin D supplement<br>Behavioral: exercise program (rebounding on a trampoline)<br>* 40 days at 30 min/d<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| urinary Ca-41/Ca-40 ratio |  | March 2010 to January 2011 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| biomarkers of bone metabolism |  | March 2010 to January 2011 | 
| urinary iodine | Comparison of spot and 24 h urine samples for the assessment of iodine status (substudy, not related to vitamin D intervention) | August 2009 to December 2010 |