Vitamin D, Insulin Sensitivity, and Vascular Associations in Adolescents

NCT01041365 | Completed DMC

• 1 other identifier: F090824002
• Study Type: observational
• Target: 62
• Locations: 1 country
• Sites: 1

Brief Summary

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).

Conditions

Insulin Sensitivity; Flow-mediated Dilation; Arterial Stiffness

Keywords

insulin sensitivity; vascular function; flow-mediated dilation; arterial stiffness; ethnicity; adolescents; females; glucose tolerance; diabetes; hypertension; cardiovascular

Outcome Measures

Primary Outcomes (1)

• Insulin Sensitivity

  Cross sectional study: at the first study visit

Secondary Outcomes (1)

• Vascular Function

  Cross sectional study: at the second study visit, within 2 weeks of first study visit

Study Arms (1)

Healthy adolescents

Healthy adolescent African American and Caucasian females, ages 14-18

Eligibility Criteria

• Age: 14 Years - 18 Years
• Sex: female
• Healthy Volunteers: Yes
• Age Groups: Child (0-17), Adult (18-64)
• 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

You may qualify if:

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

You may not qualify if:

• 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

Sponsors & Collaborators

• University of Alabama at Birmingham: lead

Study Sites (1)

University of Alabama

Birmingham, Alabama, 35243, United States

Location

Related Publications (2)

• Ashraf AP, Huisingh C, Alvarez JA, Wang X, Gower BA. Insulin resistance indices are inversely associated with vitamin D binding protein concentrations. J Clin Endocrinol Metab. 2014 Jan;99(1):178-83. doi: 10.1210/jc.2013-2452. Epub 2013 Dec 20.

  PMID: 24170105 DERIVED

• Alvarez JA, Gower BA, Calhoun DA, Judd SE, Dong Y, Dudenbostel T, Scholl J, Ashraf AP. Serum 25-hydroxyvitamin D and Ethnic Differences in Arterial Stiffness and Endothelial Function. J Clin Med Res. 2012 Jun;4(3):197-205. doi: 10.4021/jocmr965w. Epub 2012 May 15.

  PMID: 22719806 DERIVED

Biospecimen

Retention: SAMPLES WITHOUT DNA

Serum

MeSH Terms

Conditions

Insulin Resistance; Diabetes Mellitus; Hypertension

Condition Hierarchy (Ancestors)

Hyperinsulinism; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Vascular Diseases; Cardiovascular Diseases

Study Officials

• Ambika Ashraf, MD

  University of Alabama at Birmingham

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor, Pediatrics

Study Record Dates

• First Submitted: December 28, 2009
• First Posted: December 31, 2009
• Study Start: December 1, 2009
• Primary Completion: December 1, 2012
• Study Completion: December 1, 2013
• Last Updated: January 14, 2014

Record last verified: 2014-01

Locations

US (1)