Vitamin D, Cardiovascular Disease, and African Americans

Study Overview
=================
Brief Summary
-----------------
African-Americans have higher rates of cardiovascular disease morbidity and mortality, as well as vitamin D deficiency. Multiple observational studies have demonstrated an increased risk of vitamin D deficiency in African Americans with type 2 diabetes and correlation between cardiovascular disease and vitamin D levels; however, there is a lack of interventional trials exploring this connection. The objective of this proposal is to address the hypothesis that treatment of vitamin D deficiency in African Americans with type 2 diabetes will improve subclinical markers of cardiovascular disease.

Detailed Description
-----------------
This study will be a double blinded, randomized controlled trial of vitamin D3 supplementation, 4,000 international units per day versus 600 international units per day, for one year to determine the effects on markers of subclinical cardiovascular disease in African Americans with type 2 diabetes and vitamin D deficiency. Outcome assessment will focus on changes in carotid intima-medial thickness (CIMT - ultrasound of the thickness of blood vessels in the neck), as well as markers of systemic inflammation.

Official Title
-----------------
Vitamin D and Early Markers of Cardiovascular Disease in African Americans

Conditions
-----------------
Vitamin D Deficiency, Type 2 Diabetes Mellitus, Cardiovascular Disease

Intervention / Treatment
-----------------
* Dietary Supplement: Vitamin D3
* Dietary Supplement: Vitamin D3
* Dietary Supplement: Calcium carbonate


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: African Americans of both genders Age 50-70 years Type 2 diabetes (A1C < 9.0%), on stable therapy with oral medications, insulin, or a combination 25(OH)D level < 20 ng/ml BP < 140/90 mmHg; LDL < 140 mg/dl Exclusion Criteria: Pregnancy Cardiovascular disease Stage 3 or worse chronic kidney disease High urine or serum calcium or history of recurrent kidney stones Unstable medical conditions or major systemic diseases such as malignancy

Ages Eligible for Study
-----------------
Minimum Age: 50 Years
Maximum Age: 70 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Vitamin D 4000 IU<br>PO daily | Dietary Supplement: Vitamin D3<br>* Multivitamin containing cholecalciferol 4000 units orally daily<br>* Other names: Cholecalciferol;Dietary Supplement: Calcium carbonate<br>* 500 mg orally twice daily<br>|
| Active Comparator: Vitamin D 600 IU<br>PO daily | Dietary Supplement: Vitamin D3<br>* Multivitamin containing cholecalciferol 600 units orally daily<br>* Other names: Cholecalciferol;Dietary Supplement: Calcium carbonate<br>* 500 mg orally twice daily<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in carotid intima-medial thickness |  | 0, 6, and 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in systemic inflammatory markers |  | 0, 6, and 12 months | 
| Serum calcium |  | 0, 1, 3, 6, 9, and 12 months | 
| Urinary Calcium |  | 0, 1, 3, 6, 9, and 12 months |