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Vascular Function, Insulin Sensitivity, and Vitamin D (VIVID)

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 African Americans (AA) and White Hispanics (WH) is responsible for ethnic differences in insulin sensitivity and hypertension in AA, WH and European Americans (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 and WH 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), White Hispanics (WH), 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: Vitamin D, Vascular Function, and Insulin Sensitivity in Adults [The VIVID Study

Resource links provided by NLM:

Further study details as provided by University of Alabama at Birmingham:

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

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

Biospecimen Retention:   Samples Without DNA

Enrollment: 63
Study Start Date: December 2009
Study Completion Date: December 2013
Primary Completion Date: December 2012 (Final data collection date for primary outcome measure)
Healthy adults
healthy adults with BMI below 32, between ages 19-60 yrs, both males and females


Ages Eligible for Study:   19 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
  • Healthy adults with BMI below 32
  • Both males and females
  • Ages 19-60 years
  • Race: African Americans, White Hispanics, European Americans

Inclusion Criteria:

  • African American (AA), White Hispanic (WH), and European American (EA) race
  • Ages 19-60 years
  • Negative urine pregnancy test
  • No evidence of diabetes
  • Not on medications that can affect vascular functioning or insulin sensitivity

Exclusion Criteria:

  • BMI > 32 kg/m2
  • Diabetes or any chronic diseases
  • Use of medication(s) known to influence body composition, vascular function, or glucose metabolism
  • Regular smoking
  • Regular use of illegal drugs and pregnancy
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Please refer to this study by its identifier: NCT01041547

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, University of Alabama at Birmingham Identifier: NCT01041547     History of Changes
Other Study ID Numbers: F091023002
Study First Received: December 28, 2009
Last Updated: January 13, 2014

Keywords provided by 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
Vitamin D
Hypoglycemic Agents
Physiological Effects of Drugs
Growth Substances
Bone Density Conservation Agents processed this record on March 28, 2017