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The Effect of Vitamin D Supplementation on Glucose Metabolism in Non-Diabetic African American Adults (AVIS)

This study has been completed.
Information provided by:
Augusta University Identifier:
First received: June 4, 2010
Last updated: June 9, 2010
Last verified: June 2010

Type 2 diabetes is more common among African Americans than Caucasians. African Americans are also at a higher risk for lower levels of vitamin D compared to other ethnic groups. The investigators don't yet know if there is a connection between not having enough vitamin D and type 2 diabetes in African Americans. Researchers have found that the less vitamin D Caucasians had the higher the chance they would have type 2 diabetes but it is less clear if this is the case for African Americans. The investigators want to better understand how vitamin D status and diabetes risk are linked in African Americans. Also, the investigators want to see if supplementation with vitamin D will improve your blood pressure, blood sugar, & insulin. All of these are in some way related to diabetes. The investigators want to measure changes in blood sugar & blood pressure in people who do not have diabetes with the hope of learning new information to help treat those that do have diabetes.

The investigators hypothesize that vitamin D status is related to diabetes risk measured by hemoglobin A1c (a test of glucose level over time), fasting glucose and insulin in non-diabetic African American adults and that body weight status may affect vitamin D status in response to vitamin D supplements compared to placebo.

Condition Intervention
Type 2 Diabetes Dietary Supplement: vitamin D3, cholecalciferol Dietary Supplement: Inactive comparator

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Participant, Investigator)
Primary Purpose: Prevention
Official Title: The Effect of Vitamin D Supplementation on Glucose Metabolism in Non-Diabetic African American Adults

Resource links provided by NLM:

Further study details as provided by Augusta University:

Primary Outcome Measures:
  • Fasting glucose level before, mid-way through, and after the vitamin D3 supplement or placebo trial. [ Time Frame: 16 weeks ]

Secondary Outcome Measures:
  • Serum 25-OH D levels in response to vitamin D3 supplement or placebo across a range of adiposity [ Time Frame: 16 weeks ]

Enrollment: 48
Study Start Date: January 2010
Study Completion Date: May 2010
Primary Completion Date: May 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Vitamin D3 supplement
60,000 IU vitamin D3 oral supplement provided every four weeks at weeks 0, 4, 8, and 12 in the form of one 50,000 and two 5,000 IU vitamin D3 supplements in gelcap form.
Dietary Supplement: vitamin D3, cholecalciferol
1 gelcap of 50,000 IU vitamin D3 plus 2 gelcaps of 5,000 IU vitamin D3 each; a total of 60,000 IU vitamin D3 dosed four weeks apart at weeks 0, 4, 8, and 12 of the 16 week study.
Placebo Comparator: Sugar Pill
Inactive placebo tablets identical in appearance to the active comparator provided every four weeks at weeks 0,4,8,and 12.
Dietary Supplement: Inactive comparator
The inactive comparator dose provided was identical in appearance to the active comparator but contained no vitamin D3

Detailed Description:
Participants will be randomly assigned to receive either a 60,000 IU vitamin D3 supplement every four weeks or an inactive placebo. All investigators and the participants will be blinded to the assignment group of each participant until all testing is completed.

Ages Eligible for Study:   19 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • African American by self-report
  • In good health

Exclusion Criteria:

  • Diagnosis of diabetes
  • Health problems/medication affecting calcium and/or vitamin D metabolism
  • Current use of vitamin/mineral/herbal/nutritional supplements
  • Inability to swallow pills
  • Pregnancy
  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 identifier: NCT01141192

United States, Georgia
Medical College of Georgia
Augusta, Georgia, United States, 30912
Sponsors and Collaborators
Augusta University
Study Director: Yanbin Dong, MD, PhD Augusta University
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Jennifer Pederson-White, DO, Medical College of Georgia Identifier: NCT01141192     History of Changes
Other Study ID Numbers: 0910091
Study First Received: June 4, 2010
Last Updated: June 9, 2010

Keywords provided by Augusta University:
vitamin D status
25-OH D
ionized calcium
fasting glucose
hemoglobin A1c
fasting insulin
glucose metabolism
HOMA index
blood lipids
type 2 diabetes
body fat percentage
dual energy x-ray absorptiometry
pulse wave velocity
arterial stiffness
flow-mediated dilation
African American
inflammatory markers

Additional relevant MeSH terms:
Diabetes Mellitus, Type 2
Diabetes Mellitus
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases
Vitamin D
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents processed this record on July 19, 2017