Magnitude of Changes in 25 OH Vitamin D3 Levels After Vitamin D3 Supplementation

Study Overview
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Brief Summary
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Vitamin D deficiency is common world wide. 25 OH vitamin D level is the best indicator of vitamin D status. The determination of the appropriate dose of vitamin D supplement is essential for management of vitamin D deficiency as well as for designing vitamin D fortification programs. The increments in 25 OH vitamin D levels following various doses of vitamin D supplement for different genders, body weights, and starting 25 OH vitamin D level have not been well defined. The time course of depletion of repleted vitamin D stores is also not known. The investigators plan to conduct a double blind randomized study on 9 cohorts to determine levels of 25 OH vitamin D following supplementation with different doses of vitamin D3 for 5 months and their withdrawal for 3 months.

Official Title
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Magnitude of Changes in 25 OH Vitamin D3 Levels After Vitamin D3 Supplementation: A Randomized Controlled Study

Conditions
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Vitamin D Deficiency

Intervention / Treatment
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* Drug: vitamin D3 1000 IU orally daily for 5 months
* Drug: vitamin D3 3000 IU orally daily for 5 months
* Drug: vitamin D3 5000 IU orally daily for 5 months
* Drug: Placebo orally daily for 5 months


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adults living in Riyadh area who consume no more than one serving of milk/day, do not take vitamin supplement, habitually have less than 10 hr of sun exposure per week, don't suffer from granulomatous conditions, liver disease, or kidney disease, and don't take anticonvulsants, barbiturates, or steroids. Individuals with with total 25 OH vitamin D level exceeding 100 nmol/l will be excluded from the study. Individuals with 25 OH vitamin D levels less than 20 nmol/L will be excluded from the placebo arm.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: vitamin D3 1000 IU<br> | Drug: vitamin D3 1000 IU orally daily for 5 months<br> <br> |
| Active Comparator: Vitamin D3 3000 IU<br> | Drug: vitamin D3 3000 IU orally daily for 5 months<br> <br> |
| Active Comparator: Vitamin D3 5000 IU<br> | Drug: vitamin D3 5000 IU orally daily for 5 months<br> <br> |
| Placebo Comparator: Placebo<br> | Drug: Placebo orally daily for 5 months<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Slope of 25 OH vitamin D3 level vs vitamin D3 dose | The primary endpoint is the slope of the dose (vitamin D3)- response (25 OH vitamin D3 level) curve for each cohort. The slope of the placebo group will be used to determine changes in 25 OH vitamin D3 levels that are not related to study intervention. The slope will be determined over 5 months. | 5 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| slope of vitamin D3 level vs vitamin D3 dose | slope of vitamin D3 level vs vitamin D3 dose over 5 months | 5 months | 
| incidence of hypercalcemia | incidence of hypercalcemia over 8 months | 8 months | 
| incidence of hypercalciuria | incidence of hypercalciuria over 8 months | 8 months | 
| slope of decline of 25 OH vitamin D3 level vs time | slope of decline of 25 OH vitamin D3 level vs time over 3 months | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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vitamin D3, 25 OH vitamin D3 level