The Effect of Vitamin D Supplementation on Glucose Metabolism in Non-Diabetic African American Adults (AVIS)
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.
Study Overview
Status
Status
Conditions
Conditions
Intervention / Treatment
Intervention / Treatment
Detailed Description
Study Type
Study Type
Enrollment (Actual)
Enrollment
Phase
Phase
- Not Applicable
Contacts and Locations
Study Locations
-
-
Georgia
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Augusta, Georgia, United States, 30912
- Medical College of Georgia
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-
Participation Criteria
Eligibility Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
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
Study Plan
How is the study designed?
Design Details
- Primary Purpose: PREVENTION
- Allocation: RANDOMIZED
- Interventional Model: PARALLEL
- Masking: DOUBLE
Number of Arms
Arms and Interventions
Participant Group / ArmParticipant Group / Arm |
Intervention / TreatmentIntervention / 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.
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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.
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The inactive comparator dose provided was identical in appearance to the active comparator but contained no vitamin D3
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What is the study measuring?
Primary Outcome Measures
Primary Outcome Measures
Outcome Measure |
Time Frame |
|---|---|
|
Fasting glucose level before, mid-way through, and after the vitamin D3 supplement or placebo trial.
Time Frame: 16 weeks
|
16 weeks
|
Secondary Outcome Measures
Secondary Outcome Measures
Outcome Measure |
Time Frame |
|---|---|
|
Serum 25-OH D levels in response to vitamin D3 supplement or placebo across a range of adiposity
Time Frame: 16 weeks
|
16 weeks
|
Collaborators and Investigators
Sponsor
Sponsor
Investigators
Investigators
- Study Director: Yanbin Dong, MD, PhD, Augusta University
Publications and helpful links
General Publications
- Liu E, Meigs JB, Pittas AG, McKeown NM, Economos CD, Booth SL, Jacques PF. Plasma 25-hydroxyvitamin d is associated with markers of the insulin resistant phenotype in nondiabetic adults. J Nutr. 2009 Feb;139(2):329-34. doi: 10.3945/jn.108.093831. Epub 2008 Dec 23.
- Pittas AG, Dawson-Hughes B. Vitamin D and diabetes. J Steroid Biochem Mol Biol. 2010 Jul;121(1-2):425-9. doi: 10.1016/j.jsbmb.2010.03.042. Epub 2010 Mar 18.
- Voidonikola PT, Stamatelopoulos KS, Alevizaki M, Kollias GE, Zakopoulos NA, Lekakis JP, Anastasiou E, Theodorakis MJ, Pittas AG, Papamichael CM. The association between glycemia and endothelial function in nondiabetic individuals: the importance of body weight. Obesity (Silver Spring). 2008 Dec;16(12):2658-62. doi: 10.1038/oby.2008.431. Epub 2008 Oct 9.
- Liu E, Meigs JB, Pittas AG, Economos CD, McKeown NM, Booth SL, Jacques PF. Predicted 25-hydroxyvitamin D score and incident type 2 diabetes in the Framingham Offspring Study. Am J Clin Nutr. 2010 Jun;91(6):1627-33. doi: 10.3945/ajcn.2009.28441. Epub 2010 Apr 14.
- Zhu H, Guo D, Li K, Pedersen-White J, Stallmann-Jorgensen IS, Huang Y, Parikh S, Liu K, Dong Y. Increased telomerase activity and vitamin D supplementation in overweight African Americans. Int J Obes (Lond). 2012 Jun;36(6):805-9. doi: 10.1038/ijo.2011.197. Epub 2011 Oct 11.
Study record dates
Study Major Dates
Study Start
Study Start
Primary Completion (ACTUAL)
Primary Completion
Study Completion (ACTUAL)
Study Completion
Study Registration Dates
First Submitted
First Submitted
First Submitted That Met QC Criteria
First Submitted That Met QC Criteria
First Posted (ESTIMATE)
First Posted
Study Record Updates
Last Update Posted (ESTIMATE)
Last Update Posted
Last Update Submitted That Met QC Criteria
Last Update Submitted That Met QC Criteria
Last Verified
Last Verified
More Information
Terms related to this study
Keywords
- type 2 diabetes
- African American
- adiposity
- vitamin D status
- pulse wave velocity
- flow-mediated dilation
- arterial stiffness
- inflammatory markers
- HOMA index
- glucose metabolism
- hemoglobin A1c
- PTH
- fasting insulin
- blood lipids
- dual energy x-ray absorptiometry
- body fat percentage
- ionized calcium
- fasting glucose
- 25-OH D
Additional Relevant MeSH Terms
Other Study ID Numbers
Other Study ID Numbers
- 0910091
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