Vitamin D, Bones, Nutritional and Cardiovascular Status

Study Overview
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Brief Summary
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Vitamin D is not seen anymore only as a phosphocalcic hormone, but also as having an effect on global health (anti-infective, anti-inflammatory, anti-tumour roles and cardiovascular protection). The link between vitamin D deficiency and osteomalacia lesions is well-known. In paediatrics, systematic vitamin D supplementation of infants and toddlers, associated with milk enrichment, has allowed an almost total disappearance of rickets. Vitamin D repletion was defined as the minimal concentration that enables the prevention of rickets in children and osteomalacia in adults, that is approximately 8 ng/mL (20 nmol/L). However, in 2010, most of the international experts agreed to set minimal threshold of 25 OH vitamin D serum concentration, higher than the one previously admitted, with a limit of 20 ng/mL (50 nmol/L) to define a vitamin D deficiency and a limit of 30 ng/mL (75 nmol/L) to define vitamin D insufficiency in adults. In the paediatric population, the consensus is less obvious and we consider that a serum concentration of minimum 20 ng/mL is necessary. A study on more than 200 children from Lyon, followed in the paediatric nephrology unit and having a renal function normal or sub-normal, demonstrated an important prevalence of vitamin D deficiency (75%) in adolescents and pre-adolescents. Concurrently, the appearance of new bone imaging techniques (especially high-resolution peripheral quantitative computed tomography HR-pQCT) improved bone status evaluation in a non-invasive manner. Given the new pathophysiological data on pleiotropic role of vitamin D (bone, cardiovascular system, adipose tissue) and given the proportion of French children possibly suffering from vitamin D deficiency, it seems urgent to actualize current recommendations regarding systematic supplementation in vitamin D. This transversal study on 200 healthy children and adolescents will allow to have an overview of vitamin D status in French healthy children and adolescents, studying with non-invasive, safe, reliable and innovative tools, the theoretical targets of vitamin D (bones, cardiovascular system and nutritional status); and then to lay the foundations of therapeutic trials aiming to evaluate the mode of vitamin D supplementation for healthy children and adolescents; while having a cohort for HR-pQCT measurements, that will allow us to have French reference range in a 10-17 year-old population, for this innovative, non-invasive and low radiation exposure technique.

Detailed Description
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To study the correlation between bone assessment by high-resolution peripheral quantitative computed tomography (HR-pQCT) and vitamin D serum concentration.

Official Title
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Are Bone, Nutritional and Cardiovascular Status of French Children and Adolescents, Correlated With Their Vitamin D Status?

Conditions
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Vitamin D

Intervention / Treatment
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* Other: Exploration of Vitamin D roles


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 10 year-old <or= Age < 18 year-old Without mobility handicap (medical walker, crutch, wheelchair…) Written informed consent (signed by parents) Exclusion Criteria: History of treatment with growth hormone History of treatment with oral corticoids, taken over more than 3 consecutive months Current treatment with growth hormone, corticoids or anti-calcineurin Treatment with aspirin or nonsteroidal anti-inflammatory drug within the last three weeks Treatment with paracetamol within the last week Chronic pathology with an impact on growth: Parenteral nutrition Chronic inflammatory disease (rheumatologic or digestive notably) System diseases (lupus, granulomatosis, vascularitis) Renal failure Diabetes Serious intercurrent disease (infection, neoplasia) Ongoing pregnancy Patient unaffiliated with the French universal healthcare system.

Ages Eligible for Study
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Minimum Age: 10 Years
Maximum Age: 17 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: Health Services Research
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Exploration of Vitamin D roles<br>Various exams will be performed during two visits (the same day or within three months) in order to answer the objectives of the study. | Other: Exploration of Vitamin D roles<br>* Visit 1: questioning, physical examination, blood sampling (including plasma collection for future genetic analyses), carotid ultrasound Visit 2 (same day as visit 1 or maxi 3 months later): HR-pQCT, dual energy x-ray absorptiometry (DXA), iontophoresis of acetylcholine and sodium nitroprusside<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| To study the correlation between the results of bone microarchitecture obtained by high-resolution peripheral quantitative computed tomography (HR-pQCT) and vitamin D serum concentration. | The HR-pQCT evaluates bones down to the level of the tiny individual elements that nature configures in a way that makes bones as strong as possible. HR-pQCT measures bone density and quantifies the three dimensional geometry, strength and microarchitecture of bone at the lower arm (radius) and lower leg (tibia). | up to 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Values and standard deviation of 25-OH vitamin D3 plasma concentration concentration in the population studied. | Blood intake. | Once. At inclusion (V1). | 
| To study the correlation between vitamin D plasma concentration and nutritional and pubertal status, cardiovascular status, inflammatory status . | Nutritional and pubertal status will be assessed thanks to: Body Mass Index, Dual-energy X-ray Absorptiometry, adipokines level. Cardiovascular status will be assessed thanks to arterial pressure, Intima-media Thickness (IMT), Extra-media Thickness (EMT), lipid profile, endothelial function. IMT and EMT will be obtained using carotid ultrasound. Endothelial function will be evaluated following a protocol of iontophoresis of acetylcholine and sodium nitroprusside. Inflammatory status will be measured looking at C-reactive protein plasma level. | up to 3 months | 
| To evaluate the relation between bone parameters (HR-pQCT) and adipokines; and the relation between bone parameters and cardio-vascular data (blood pressure, IMT, EMT, lipid profile, endothelial function). |  | up to 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vitamin D, bone, cardiovascular status, nutritional status