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Vitamin D, Insulin Sensitivity, and Vascular Associations in Adolescents (DIVA)

This study has been completed.
Information provided by (Responsible Party):
Ambika Ashraf, M.D., University of Alabama at Birmingham Identifier:
First received: December 28, 2009
Last updated: January 13, 2014
Last verified: January 2014

The overall objectives of this study are to examine the relationships between circulating vitamin D, insulin sensitivity, and multiple indices of vascular function and to examine whether vitamin D deficiency in AA is responsible for ethnic differences in insulin sensitivity and hypertension in AA and EA, as well as mechanisms underlying the association between insulin resistance and blood pressure. We hypothesize that 1) serum 25(OH)D is associated with insulin sensitivity and vascular functioning, independent of adiposity, 2) lower insulin sensitivity and vascular functioning in AA relative to EA is due to lower circulating 25(OH)D in AA, and 3) the relationship between insulin resistance and vascular dysfunction is mediated by 25(OH)D.

Acronyms: African American (AA), European American (EA), Serum 25-hydroxy vitamin D (25()H)D, Body mass index (BMI), Alabama (AL).

Insulin Sensitivity Flow-mediated Dilation Arterial Stiffness

Study Type: Observational
Study Design: Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Serum 25-hydroxyvitamin D, Vascular Functioning, and Insulin Sensitivity in Adolescent Girls [The DIVA Study (Vitamin D, Insulin, and Vascular Associations)] (Pediatric Physician Training in Translational Research)

Resource links provided by NLM:

Further study details as provided by Ambika Ashraf, M.D., University of Alabama at Birmingham:

Primary Outcome Measures:
  • Insulin Sensitivity [ Time Frame: Cross sectional study: at the first study visit ]

Secondary Outcome Measures:
  • Vascular Function [ Time Frame: Cross sectional study: at the second study visit, within 2 weeks of first study visit ]

Biospecimen Retention:   Samples Without DNA

Enrollment: 62
Study Start Date: December 2009
Study Completion Date: December 2013
Primary Completion Date: December 2012 (Final data collection date for primary outcome measure)
Healthy adolescents
Healthy adolescent African American and Caucasian females, ages 14-18


Ages Eligible for Study:   14 Years to 18 Years   (Child, Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Healthy adolescent African American and European American teenagers, ages 14-18, will be recruited form the Birmingham, AL community

Inclusion Criteria:

  • African American or Caucasian ethnicity
  • Ages 14-18 yrs
  • Healthy

Exclusion Criteria:

  • BMI-for age and -sex higher than 95th centile on the Centers for Disease Control and Prevention Growth Charts
  • Use of medication(s) known to influence body composition, vascular function, or glucose metabolism
  • Pregnancy
  • Diabetes or any chronic diseases
  Contacts and Locations
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Please refer to this study by its identifier: NCT01041365

United States, Alabama
University of Alabama
Birmingham, Alabama, United States, 35243
Sponsors and Collaborators
University of Alabama at Birmingham
Principal Investigator: Ambika Ashraf, MD University of Alabama at Birmingham
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Ambika Ashraf, M.D., Associate Professor, Pediatrics, University of Alabama at Birmingham Identifier: NCT01041365     History of Changes
Other Study ID Numbers: F090824002
Study First Received: December 28, 2009
Last Updated: January 13, 2014

Keywords provided by Ambika Ashraf, M.D., University of Alabama at Birmingham:
insulin sensitivity
vascular function
flow-mediated dilation
arterial stiffness
glucose tolerance

Additional relevant MeSH terms:
Insulin Resistance
Dilatation, Pathologic
Immune System Diseases
Glucose Metabolism Disorders
Metabolic Diseases
Pathological Conditions, Anatomical
Insulin, Globin Zinc
Vitamin D
Hypoglycemic Agents
Physiological Effects of Drugs
Growth Substances
Bone Density Conservation Agents processed this record on September 21, 2017