Vitamin D, Bones, Nutritional and Cardiovascular Status
Vitamin D, Bones, Nutritional and Cardiovascular Status
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.
To study the correlation between bone assessment by high-resolution peripheral quantitative
 computed tomography (HR-pQCT) and vitamin D serum concentration.
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.