The problem of childhood obesity has reached epidemic proportions both nationally and internationally. The prevalence of obesity has tripled in the last three decades and currently 16 % of American adolescents are obese. Nearly 30% of obese adolescents demonstrate a metabolic syndrome characterized by insulin resistance and dyslipidemia. These abnormalities lead to the development of type 2 diabetes mellitus and to increased cardiovascular morbidity and mortality. Obesity is a well-known risk factor for vitamin D insufficiency and up to 80% of obese adults have been found to be insufficient in vitamin D. Observational studies in adults have shown consistent associations between low vitamin D status and prevalence of type 2 diabetes mellitus and metabolic syndrome. There is paucity of data on the prevalence of vitamin D insufficiency and its implications in obese adolescents. It is also not known whether treatment of vitamin D insufficiency in children or adults might result in improvement in insulin resistance and cardiovascular risk factors.
Hypotheses: We hypothesize that vitamin D insufficiency correlates positively with insulin resistance and cardiovascular risk in obese adolescents and that vitamin D3 supplementation decreases insulin resistance and cardiovascular risk factors in this population.
Objectives:
1. Determine if there is any correlation between serum 25(OH)D levels and HOMA-IR, HDL cholesterol and C-reactive protein, in obese adolescents.
2. Study the impact of vitamin D3 supplementation on various parameters reflecting insulin action, secretion, lipids and C-reactive protein in obese adolescents.
Inclusion Criteria:
1. Age between 12-18 years
2. BMI is at or greater than the 95th percentile for age and gender
Exclusion Criteria:
1. Subjects with 25 (OH)- D levels >100 ng/mL
2. Serum calcium >10.8 mg/dL
3. Current cancer
4. Those taking a multivitamin supplementation
5. Hepatic or renal disorders
6. Type 1 or type 2 diabetes mellitus.
7. Those receiving insulin, metformin or oral hypoglycemic medications
- Use of glucocorticoids and anti-seizure medications in the previous 6 months
- Malabsorption syndromes such as celiac disease
Last updated: 02/26/2013
NCT ID: NCT00858247
IRB Number:08-008743
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