Vitamin D Deficiency and Low Bone Mineral Content in Children

Study Overview
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Brief Summary
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The Vitamin D study is designed to investigate the effect of body fat mass on vitamin D levels in children. Earlier studies have shown that individuals with increased fat mass may have low vitamin D levels. Our specific hypothesis states that children with increased fat mass will have lower blood levels of vitamin D when compared to non-obese children.Since vitamin D is the primary hormone for bone mineralization in humans, low levels of vitamin D could lead to decreased bone mineral content in these children.

Detailed Description
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Fifty prepubertal male and female children of ages between 3-12 years will participate in this study. Of these, 25 obese children will be enrolled in the study group, and 25 non-obese children will serve as controls. All subjects will fill out a comprehensive mineral intake questionnaire as part of the study to ensure adequate calcium intake prior to the study. All subjects will collect a first morning urine sample for calcium, creatinine, and NTX. Fasting blood samples will be drawn for the following analytes: 25-hydroxyvitamin D, 1, 25-dihydroxyvitamin D, intact PTH, calcium, phosphorus, magnesium, osteocalcin, insulin, c-peptide, fasting blood glucose, leptin, and adiponectin. Bone Mineral Content will be evaluated in 16 obese subjects with vitamin D level of < 30 nmol/L.

Official Title
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The Relationship Between Vitamin D Deficiency and Low Bone Mineral Content in Children

Conditions
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Vitamin D Deficiency, Obesity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: General: Prepubertal children (males, with testicular volume of ≤ 3 cc, and girls with Tanner 1 breast) of ages 7-11 years will be enrolled in the study. Study group: Subjects with a BMI of > 95th percentile for age and sex. Control group: All control subjects will have a BMI of < 85th percentile for age and sex. Exclusion Criteria: known metabolic or genetic diseases resulting in obesity such as severe hypothyroidism, pseudohypoparathyroidism, or Cushing's disease diabetes mellitus subjects on lipid lowering medications subjects on medications known to impact body weight or calcium homeostasis subjects with a history of recent significant weight loss or gain

Ages Eligible for Study
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Minimum Age: 3 Years
Maximum Age: 12 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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Obese<br>Chilren with BMI of >95th percentile | |
| Non-obese<br>Children with BMI of <85th percentile | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Bone mineral content |  | Baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vitamin D deficiency, insulin resistance, obesity, bone