Assessment of Influence of Vitamin D on Insulin Secretion and Sensitivity in Obese Teenage Girls

Study Overview
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Brief Summary
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The purpose of the study is to assess the relationship between vitamin D status and insulin- glucose dynamics in obese Adolescents. The study is intended to assess the difference in the insulin sensitivity before and after correction of vitamin D deficiency.

Detailed Description
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The vitamin D deficient subjects are identified initially through an existing study. Those identified with vitamin D deficiency are notified and subsequently treated with standard therapy for vitamin D deficiency as part of their clinical care. Patients who self report that they have taken the treatment are enrolled in this study. Patients will be evaluated in this study with measurement of serum 25 OH D level, PTH and oral glucose tolerance test. The study will assess if there is improvement in glucose- insulin sensitivity dynamics once the serum 25OH D level is normalized

Official Title
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Assessment of Influence of Vitamin D on Insulin Secretion and Sensitivity in Obese Teenage Girls (Assessment of Prevalence of Vitamin D Deficiency in Obese Teenage Girls and Influence of Vitamin D on Insulin Secretion and Sensitivity)

Conditions
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Vitamin D Deficiency, Insulin Resistance, Insulin Sensitivity, Obesity

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Female adolescents who are menarchal BMI is 95th centile, for age and sex Patients will be screened for vitamin D deficiency through an existing study. Those found to be vitamin D deficient will be given standard treatment of vitamin D deficiency. In this study, patients who self report that they had taken the treatment for vitamin D will be screened for serum 25 OH D level Exclusion Criteria: Children with diabetes, other endocrine or acute or chronic medical illnesses, children on oral contraceptive pills, diuretics and anticonvulsant medications

Ages Eligible for Study
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Minimum Age: 13 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Obese female adolescents<br>Obese adolescents will be screened for vitamin D deficiency through an existing study. Those found to be vitamin D deficient will be given standard treatment of vitamin D deficiency. In this study, patients who self report that they had taken the treatment for vitamin D will be screened for serum 25 OH D level and will undergo OGTT. The OGTT results as well as insulin resistance indices will be compared to their initial values. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The insulin secretory capacity and insulin resistance indices are the outcome of interest in this study. |  | December 2009 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| We will evaluate whether the relationship of obesity and insulin resistance and the defective insulin secretory capacity is modulated by vitamin D status |  | December 2009 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Vitamin D deficiency, Insulin resistance, Glucose- Insulin dynamics, Obese adolescents