Effect of Vitamin D3 on Vascular Function

The recruitment status of this study is unknown because the information has not been verified recently.
Verified January 2012 by Charles Drew University of Medicine and Science.
Recruitment status was  Active, not recruiting
Sponsor:
Information provided by (Responsible Party):
Keith Norris, Charles Drew University of Medicine and Science
ClinicalTrials.gov Identifier:
NCT00948298
First received: July 28, 2009
Last updated: January 22, 2012
Last verified: January 2012
  Purpose

Vitamin D is a natural nutrient. A little comes from our normal daily diet. Most of it comes from our skin after we have been in sunlight. If we have darker skin, we make less vitamin D. Vitamin D balances the calcium in our body. If our vitamin D levels get too low it can cause health problems. It may increase our chance of getting high blood pressure or diabetes. Another problem we may have if our vitamin D levels are low is that our blood vessels may not work normally. These are important health problems for anyone. Because African Americans have darker skin, they are more likely than most other racial/ethnic groups to have low vitamin D levels. This study will look at treating African Americans with low vitamin D levels.

The goal of this study is to see how vitamin D helps blood vessels work. The investigators will do this study in African Americans who are overweight, have high blood pressure and have low vitamin D levels. The investigators will see if getting the vitamin D level to a normal value will improve how blood vessels work. The dose of vitamin D that will be given in this study is a high dose that is given to people with low vitamin D levels.


Condition Intervention
Vitamin D Deficiency
Drug: vitamin D
Drug: Placebo

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Prevention
Official Title: The Effect of Cholecalciferol (Vitamin D3) on Vascular Function and Cardiovascular Risk Factors

Resource links provided by NLM:


Further study details as provided by Charles Drew University of Medicine and Science:

Primary Outcome Measures:
  • The primary outcome variable is pulse wave velocity for vascular stiffness assessed by radial artery tonometry (via SphygmoCor). The hypothesis is that a greater decrease in the PWV will occur with the Vitamin D3 treatment. [ Time Frame: one year ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Improved vascular/endothelial function as determined by measuring non-invasive vascular finger plethysmography (via EndoPat),sitting and 24 hour ambulatory blood pressure. [ Time Frame: one year ] [ Designated as safety issue: No ]

Enrollment: 130
Study Start Date: July 2009
Estimated Study Completion Date: April 2012
Primary Completion Date: July 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: placebo and vitamin D
Subjects with low vitamin D levels, diabetes and hypertension
Drug: vitamin D
Two 50,000 IU tablets of oral Vitamin D3 will be given every 4 weeks.
Drug: Placebo
Two tablets of oral placebo (microcrystalline cellulose),matching in appearance to the Vitamin D3, will be given every 4 weeks.

Detailed Description:

Cardiovascular Disease (CVD) and related disorders remain the leading cause of death in the nation. Hypovitaminosis D has been linked not only to several cardiovascular (CV) risk factors including hypertension, diabetes, obesity but also to increased rates of CVD. Thus,hypovitaminosis D presents a common pathway for a select subgroup with a clustering of CV risk factors in a profile that is predominant among ethnic minorities. Indeed, hypovitaminosis D is highly prevalent with an estimated 55% of the US adult population having levels at or below 30 ng/ml, and over 80% of African Americans having suboptimal values. Thus, we propose a twelve week randomized double-blind, placebo controlled pilot trial to assess the effect on vascular function and CV risk factors of 100,000 IU Vitamin D3 given every 4 weeks to overweight, hypertensive African-Americans with hypovitaminosis D. To our knowledge, the proposed project is the first to assess the effect of 'high-dose' Vitamin D3 administration on vascular function.We believe this study is also the first to examine the impact at a molecular level of Vitamin D3 repletion on the key mediators of cardio-metabolic pathways in humans. If our study results support our working hypothesis, we will be positioned to propose a larger scale study to detect a therapeutic effect on more definitive, clinical cardiovascular endpoints across a more diverse population.

  Eligibility

Ages Eligible for Study:   18 Years to 70 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • Males or females, 18-70 years of age and self-identified as African-American or Black
  • Hypertension
  • If a potential study patient is not on treatment their SBP must be > 130 mmHg, or DBP > 85 mmHg, and SBP must be <160 mmHg and DBP must be < 105 mmHg.
  • If a potential study patient is on treatment then the SBP must be <160 mmHg and DBP must be < 105 mmHg
  • Screening Vitamin D (D2 and D3 level) between 10 and 25 ng/ml (normal level > 30 ng/ml)
  • Body mass index (BMI) > 25 kg/m2

Exclusion Criteria:

  • Poorly controlled high blood pressure (SBP >160 mmHg or DBP > 105 mmHg)
  • Diabetes (fasting blood sugar > 125 mg/dl, or HbA1c > 6.5%)
  • Screening Vitamin D (D2 and D3 level) < 10 ng/ml or > 25 ng/ml
  • Estimated glomerular filtration rate (eGFR) < 45 ml/min
  • Evidence of disease resulting in hypercalcemia
  • History of kidney stones
  • History of drug, alcohol, or illicit substance abuse within the past 6 months
  • History of another chronic disease which the investigator feels should preclude the subject from entering the study
  • Liver function tests (LFTs) greater than twice the upper limit of normal
  • Subjects requiring chronic use of nonsteroidal anti-inflammatory drugs, aspirin, or other drugs that may affect the measurement of reactive oxidative species
  • Subjects requiring treatment with other vitamin D preparations containing more than 400 IU of vitamin D
  • Subjects requiring chronic use of immunosuppressive therapy or corticosteroids
  • Recent (< 6 months) myocardial infarction, stroke, or hospitalization for congestive heart failure
  • Allergy/intolerance: known allergy to oral vitamin D or microcrystalline cellulose
  Contacts and Locations
No Contacts or Locations Provided
  More Information

No publications provided

Responsible Party: Keith Norris, Professor of Medicine; Executive VP for Research and Health Affairs, Charles Drew University of Medicine and Science
ClinicalTrials.gov Identifier: NCT00948298     History of Changes
Other Study ID Numbers: IRB#08-05-2170-01, NIH U54RR022762
Study First Received: July 28, 2009
Last Updated: January 22, 2012
Health Authority: United States: Institutional Review Board

Keywords provided by Charles Drew University of Medicine and Science:
cardiovascular disease
vitamin D
african american
low vitamin D levels

Additional relevant MeSH terms:
Vitamin D Deficiency
Avitaminosis
Deficiency Diseases
Malnutrition
Nutrition Disorders
Cholecalciferol
Vitamin D
Ergocalciferols
Vitamins
Micronutrients
Growth Substances
Physiological Effects of Drugs
Pharmacologic Actions
Bone Density Conservation Agents

ClinicalTrials.gov processed this record on April 17, 2014