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Effect of Vitamin D3 Supplementation on Insulin Resistance and Cardiovascular Risk Factors in Obese Adolescents

This study has been completed.
Sponsor:
Collaborators:
Thrasher Research Fund
Information provided by:
Mayo Clinic
ClinicalTrials.gov Identifier:
NCT00858247
First received: March 5, 2009
Last updated: May 13, 2014
Last verified: May 2014
  Purpose

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.


Condition Intervention Phase
Obesity
Dietary Supplement: Vitamin D3
Phase 2

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Significance of Vitamin D Status in Obese Adolescents- A Pilot Study to Examine the Effect of Vitamin D3 Supplementation on Insulin Resistance and Cardiovascular Risk Factors

Resource links provided by NLM:


Further study details as provided by Mayo Clinic:

Primary Outcome Measures:
  • Change in Insulin Resistance After 12 Weeks of Vitamin D3 Supplementation [ Time Frame: Baseline, 12 weeks ] [ Designated as safety issue: No ]

    Insulin resistance (IR) is a physiological condition in which cells fail to respond to the normal actions of the hormone insulin. The body produces insulin, but the cells in the body become resistant to insulin and are unable to use it as effectively, leading to hyperglycemia. Beta cells in the pancreas subsequently increase their production of insulin, further contributing to hyperinsulinemia.

    From the fasting glucose and insulin measurements, insulin resistance was calculated by the homeostasis model assessment of insulin resistance (HOMA -IR) as: HOMA -IR = fasting insulin concentration (µU/mL) x fasting glucose concentration (mmol/L)/22.5. High HOMA-IR scores denote increased insulin resistance.



Secondary Outcome Measures:
  • Change in Total Cholesterol After 12 Weeks of Vitamin D Supplementation [ Time Frame: baseline, 12 weeks ] [ Designated as safety issue: No ]
    Less than 200 mg/dL is desirable, >200 mg/dL is borderline high, >240 mg/dL is High

  • Change in Low Density Lipoprotein (LDL) Cholesterol After 12 Weeks of Vitamin D Supplementation [ Time Frame: baseline, 12 weeks ] [ Designated as safety issue: No ]
    LDL cholesterol is considered to be the main source of cholesterol buildup and blockage in the arteries. Less than 100 mg/dL is optimal, >130 mg/dL is borderline high, >160 mg/dL is high, >190 mg/dL is very high.

  • Change in High Density Lipoprotein (HDL) Cholesterol After 12 Weeks of Vitamin D Supplementation [ Time Frame: baseline, 12 weeks ] [ Designated as safety issue: No ]
    HDL (good) cholesterol protects against heart disease, so for HDL, higher numbers are better. A level less than 40 mg/dL is low and is considered a major risk factor because it increases your risk for developing heart disease. HDL levels of 60 mg/dL or more help to lower your risk for heart disease.

  • Change in Triglycerides After 12 Weeks of Vitamin D Supplementation [ Time Frame: baseline, 12 weeks ] [ Designated as safety issue: No ]
    The current recommendation on fasting blood triglyceride levels: < 150 mg/dL is normal, >150 mg/dL is borderline high, and >200 mg/dL is high.

  • Change in High-Sensitivity C-Reactive Protein After 12 Weeks of Vitamin D Supplementation [ Time Frame: baseline, 12 weeks ] [ Designated as safety issue: No ]
    The high-sensitivity C-reactive protein test measures your risk for heart problems. <1.0 mg/L is lowest risk, 1.0-3.0 mg/L is average risk, and >3.0 mg/L is highest risk.


Enrollment: 51
Study Start Date: April 2009
Study Completion Date: December 2012
Primary Completion Date: December 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Vitamin D3-low dose
Vitamin D3 400 IU capsule, one capsule daily for 12 weeks.
Dietary Supplement: Vitamin D3
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.
Experimental: Vitamin D3-high dose
Vitamin D3 2000 IU capsule, one capsule daily for 12 weeks.
Dietary Supplement: Vitamin D3
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.

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.
  Eligibility

Ages Eligible for Study:   12 Years to 18 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00858247

Locations
United States, Minnesota
Mayo Clinic
Rochester, Minnesota, United States, 55905
Sponsors and Collaborators
Mayo Clinic
Thrasher Research Fund
Investigators
Principal Investigator: Seema Kumar, M.D. Mayo Clinic
  More Information

No publications provided

Responsible Party: Seema Kumar, M.D., Mayo Clinic
ClinicalTrials.gov Identifier: NCT00858247     History of Changes
Other Study ID Numbers: 08-008743, UL1RR024150
Study First Received: March 5, 2009
Results First Received: December 16, 2013
Last Updated: May 13, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Mayo Clinic:
vitamin D
Obesity
Insulin sensitivity
Adolescent Obesity

Additional relevant MeSH terms:
Insulin Resistance
Obesity
Body Weight
Glucose Metabolism Disorders
Hyperinsulinism
Metabolic Diseases
Nutrition Disorders
Overnutrition
Overweight
Signs and Symptoms
Cholecalciferol
Ergocalciferols
Insulin
Vitamin D
Vitamins
Bone Density Conservation Agents
Growth Substances
Hypoglycemic Agents
Micronutrients
Pharmacologic Actions
Physiological Effects of Drugs

ClinicalTrials.gov processed this record on November 27, 2014