Vitamin D and Genetics in Nutritional Rickets

Study Overview
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Brief Summary
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The purpose of this study is: To compare the response of rickets to calcium with and without vitamin D. To assess whether vitamin D increases calcium absorption in calcium deficiency rickets. To compare the response of children with and without rickets to orally administered vitamin D3 and vitamin D2 To identify mutations that influence calcium and vitamin D metabolism among families of children with rickets in Nigeria and Bangladesh. To assess the functional status of the 25-hydroxylase enzyme in families possessing a 25-hydroxylase mutation.

Detailed Description
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Previous studies of Nigerian children with rickets demonstrated the superiority of calcium over vitamin D in producing healing. It is not known whether the addition of vitamin D to calcium will produce a better response to treatment than calcium alone in Nigerian children. A previous study suggested the possibility that vitamin D may augment the effect of calcium. We will compare the response of rickets to calcium with and without vitamin D. In addition, very little human data clearly demonstrates the effect of supplemental vitamin D on calcium absorption. We will assess whether oral vitamin D increases the already high calcium absorption even further. Recent published data indicate that the increase in serum 25-hydroxyvitamin D may be more sustained with vitamin D3 than with vitamin D2. We will compare the response of Nigerian children with and without rickets to orally administered vitamin D3 and vitamin D2. Because nutritional rickets tends to run in families, we will also examine amplified DNA for evidence of mutations that influence calcium and vitamin D metabolism among families of children with rickets in Nigeria and Bangladesh. Families possessing a recently identified 25-hydroxylase mutation will be given oral vitamin D2 and vitamin D3 to determine the functional status of the 25-hydroxylase enzyme.

Official Title
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Vitamin D and Genetics in Nutritional Rickets

Conditions
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Nutritional Rickets

Intervention / Treatment
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* Dietary Supplement: Vitamin D + Calcium
* Dietary Supplement: Calcium
* Dietary Supplement: Vitamin D2
* Dietary Supplement: Vitamin D3


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical features of rickets Active rickets on X-ray Exclusion Criteria: Treatment with calcium or vitamin D in preceding 30 days

Ages Eligible for Study
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Minimum Age: 6 Months
Maximum Age: 16 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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Vitamin D + Calcium<br>Vitamin D and calcium supplementation | Dietary Supplement: Vitamin D + Calcium<br>* Vitamin D 50,000 IU orally once monthly for 6 months; Calcium carbonate (as powdered limestone) 500 mg orally twice daily for 6 months<br>* Other names: ergocalciferol;|
| Placebo Comparator: Calcium<br>Calcium supplementation | Dietary Supplement: Calcium<br>* Calcium carbonate (as powdered limestone) 500 mg orally twice daily for 6 months; Vitamin B complex (used as placebo) 1 tablet monthly for 6 months<br>* Other names: limestone;|
| Active Comparator: Vitamin D2<br>Vitamin D2 response | Dietary Supplement: Vitamin D2<br>* 50,000 IU given orally once<br>* Other names: ergocalciferol;|
| Active Comparator: Vitamin D3<br>Vitamin D3 response | Dietary Supplement: Vitamin D3<br>* Vitamin D3 50,000 IU given orally once<br>* Other names: cholecalciferol;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| XR healing of rickets |  | 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Alkaline phosphatase |  | 6 months | 
| Serum calcium |  | 6 months | 
| 25-hydroxyvitamin D |  | 6 months | 
| 1,25-dihydroxyvitamin D |  | 2 weeks | 
| Calcium absorption |  | 1 week | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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rickets, calcium, vitamin D, nutrition, child