Effect of Vitamin D Supplementation on Oral Glucose Tolerance Among Obese Adolescents

Insulin Resistance Clinical Trial

Official title:

Effect of 4,000 IU Vitamin D3 Supplementation on Oral Glucose Tolerance Among Vitamin D Deficient Obese Adolescent

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01856946
• Other study ID #: 1203853
• Status: Completed
• Phase: N/A
• First received: May 10, 2013
• Last updated: October 6, 2016
• Start date: May 2013
• Est. completion date: February 2014

Study information

• Verified date: October 2016
• Source: University of Missouri-Columbia
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Interventional

Clinical Trial Summary

Childhood obesity is a rapidly growing epidemic in the US and the world. Current estimates suggest that 30% of our nation's children are either overweight ot obese. Obesity is a major risk factor towards the development of insulin resistance, which, in turn is a major risk factor for the development of type 2 diabetes. Prior research has suggested that vitamin D therapy may be a safe, inexpensive, and effective method of reducing insulin resistance and a person's risk of developing diabetes.

The investigators' prior studies have shown that daily 4,000 IU vitamin D therapy is a safe and effective method of improving insulin resistance based on a calculation called the HOMA-IR.

The next step in identifying whether vitamin D truly improves insulin resistance is to use oral glucose tolerance testing (OGTT), which is a better real-life measure of insulin resistance compared to the previously used HOMA-IR.

Description:

The investigators intend to recruit 20 obese adolescent subjects from the PI's obesity clinic to participate in the study. Investigators expect 5 to drop out, therefore leaving 15 subjects to complete the study. Eligible and assenting subjects (with consent from a parent) will be admitting to the Pediatric Procedure Suite and MU Women's and Children's Hospital. They will have an IV placed in the arm by a nurse experienced with working with children. The subjects will have blood drawn from the IV checking for vitamin D level, insulin, glucose, and c-peptide level (another marker for insulin status). The subject will then be asked to drink a 75 gram glucose solution. Additional blood will be drawn from the IV site to check for glucose, insulin, and c-peptide levels at 30 minutes, 60 minutes, 90 minutes, and 120 minutes. A total of 30 mL (2 tablespoons) of blood will be drawn that day. The subject will have the IV removed and will be discharged to then take two 2,000 IU vitamin D3 pills (total 4,000 IU) daily for six months.

At a routine 3 months clinical visit, the subject will be tested for routine, standard of care, basic metabolic profile (BMP) with 4 ml of blood (less than 1 teaspoon) to assess for high calcium levels, a potential complication of vitamin D therapy. In the investigators' previous study of adolescents taking 4,000 IU vitamin D daily for six months, no subject developed a high calcium level.

At six months, the subject will return to the Pediatric procedure suite to have another OGTT and labs via IV as described above.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 15
• Est. completion date: February 2014
• Est. primary completion date: February 2014
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 9 Years to 19 Years

Eligibility

Inclusion Criteria:

• Obese adolescent (BMI >85th percentile for age)

• 9-19 years of age

• attending the ADOBE clinic at the University of Missouri

• 25OH vitamin D level within past 3 months

Exclusion Criteria:

• use of vit D supplements other than standard multi-vitamin preparation (i.e., should not be receiving vit D > 1000 IU/d)

• use of medications that interfere with vit D metabolism (e.g., anti-convulsive)

• history of hepatic or renal disorders, hypercalciuria, or hypercalcemia

• undergoing UV radiation as medical therapy

• pregnancy; cigarette smoking; current use of a tanning bed

• current type 2 diabetes

• any current antihyperglycemic medication use (e.g. metformin, insulin) less than one month prior to initial OGTT.

Study Design

Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment

Related Conditions & MeSH terms

• Insulin Resistance

Intervention

Dietary Supplement:
• 4,000 IU vitamin D3
two 2,000 IU vitamin D3 pills (total 4,000 IU) daily for six months.

Locations

Country	Name	City	State
United States	University of Missouri Adolescent Obesity Clinic	Columbia	Missouri

Sponsors (1)

Lead Sponsor	Collaborator
University of Missouri-Columbia

Country where clinical trial is conducted

United States, 

References & Publications (1)

Belenchia AM, Tosh AK, Hillman LS, Peterson CA. Correcting vitamin D insufficiency improves insulin sensitivity in obese adolescents: a randomized controlled trial. Am J Clin Nutr. 2013 Apr;97(4):774-81. doi: 10.3945/ajcn.112.050013. Epub 2013 Feb 13. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	change in oral glucose tolerance	Will obtain oral glucose tolerance tests at baseline and at 6 months to determine change	baseline and 6 months	No