Effect of Vitamin D3 Supplementation on Insulin Resistance and Cardiovascular Risk Factors in Obese Adolescents
Condition: Obesity
MeSH terms: Obesity; Insulin Resistance
Study type: Interventional
Phase: Phase 2

Summary: 
      The prevalence of obesity has reached epidemic proportions nationally as well as
      internationally. Currently, 16 % of American adolescents are obese. In adults, obesity is a
      risk factor for vitamin D insufficiency and up to 80% of obese adults have been noted to
      vitamin D insufficient. In adults, low vitamin D status appears to be associated with the
      development of type 2 diabetes and metabolic syndrome. There is little information on the
      prevalence of vitamin D insufficiency and its implications in obese adolescents.
      Additionally, it is unknown whether treatment of vitamin D insufficiency in adolescents might
      result in improvement in insulin resistance, lipids and cardiovascular risk markers.

      We hypothesize that vitamin D insufficiency correlates positively with insulin resistance and
      cardiovascular risk in obese adolescents and that vitamin D3 supplementation improves insulin
      resistance and cardiovascular risk factors in this population. The purpose of the study is to
      determine the impact of vitamin D3 supplementation on various parameters of insulin
      secretion, insulin action, lipids and C-reactive protein in obese adolescents.
    

Detailed description: 
      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 homeostasis model
           assessment of insulin resistance (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.
    

Intervention name(s): Vitamin D3
Intervention type(s): Dietary Supplement
Intervention description(s): One arm would receive vitamin D3 at a dose of 400 IU by mouth once daily for 12 weeks and the other arm would receive vitamin D3 as a single oral daily dose of 2000 IU for 12 weeks.
Intervention MeSH terms: Vitamin D; Cholecalciferol
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Prevention
Keywords: vitamin D; Obesity; Insulin sensitivity; Adolescent Obesity