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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01141192
Recruitment Status : Completed
First Posted : June 10, 2010
Last Update Posted : June 10, 2010
Information provided by:
Augusta University

Brief Summary:

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 or disease Intervention/treatment Phase
Type 2 Diabetes Dietary Supplement: vitamin D3, cholecalciferol Dietary Supplement: Inactive comparator Not Applicable

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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 48 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Prevention
Official Title: The Effect of Vitamin D Supplementation on Glucose Metabolism in Non-Diabetic African American Adults
Study Start Date : January 2010
Actual Primary Completion Date : May 2010
Actual Study Completion Date : May 2010

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
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

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

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

Information from the National Library of Medicine

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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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01141192

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

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Jennifer Pederson-White, DO, Medical College of Georgia Identifier: NCT01141192    
Other Study ID Numbers: 0910091
First Posted: June 10, 2010    Key Record Dates
Last Update Posted: June 10, 2010
Last Verified: June 2010
Keywords provided by Augusta University:
ionized calcium
vitamin D status
25-OH D
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:
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Calcium-Regulating Hormones and Agents
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