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Trial record 23 of 123 for:    hypertension "vitamin d"

Effectiveness of Vitamin D Supplementation

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: NCT02513823
Recruitment Status : Completed
First Posted : August 3, 2015
Last Update Posted : May 9, 2017
The Methodist Hospital System
Information provided by (Responsible Party):
Carolyn Moore, Texas Woman's University

Brief Summary:
This pilot study will examine the effectiveness of vitamin D supplementation on reducing blood pressure and improving endothelial function. Premenopausal African American women will be recruited. Potential subjects will have systolic and diastolic blood pressure measured following the American Heart Association Blood Pressure Guidelines. Any individual with an average blood pressure > 140/90 mmHg will be referred to their personal physician for follow up. Participants with blood pressure readings <140/90 mmHg will be consented and then instructed to record food intake for three days to estimate usual dietary intake at baseline and at the 10th week timepoint. At the baseline clinic visit a 10 week supply of vitamin D3 supplements (2,000 IU/day; Nature Made ®) will be given to participants and log sheets provided to record supplement intake. For the baseline and the 10 week visits, participants will fast overnight and refrain from consuming any caffeinated products, vitamins, or medications that may affect vascular tone, and will refrain from smoking. Three successive systolic and diastolic blood pressure measurements and the average of the last two measurements will be calculated. Anthropometric and body fat distribution assessments will be performed. Height and weight will be measured. Percent body fat will be determined by bioelectric impedance (Tanita BF-350) by C Moore. Body mass index (BMI) will be calculated as weight in kilograms (kg) divided by height squared (m2). Pulse amplitude tonometry (PAT) will be measured with the EndoPAT 2000 (Itamar Medical Ltd) which records digital pulse wave amplitude (PWA) using fingertip plethysmography. A reactive hyperemia index (RHI) measures nitric-oxide dependent changes in vascular tone. Endothelial dysfunction is classified as a RHI < 1.67 with average normal endothelial RHI values ranging between 1.7 and 2.0. Blood will be drawn for measurement of serum 25(OH)D concentrations by chemiluminescence immunoassay( Abbott Architect). Vitamin D deficiency will be defined as serum 25(OH)D levels less than 20 ng/mL (50 nmol/L) and vitamin D insufficiency as 21 to 29 ng/mL (50 to 80 nmol/L). Descriptive statistics, including means and standard deviations for continuous variables and frequencies and percentages for categorical variables, will be calculated for study variables. To answer the primary research questions, within subjects repeated measures analysis of variance (ANOVA) tests will be conducted to test if any differences in blood pressure, serum 25(OH)D concentrations, and RHI are statistically different after 10 weeks of supplementation with 2,000 IU/d of vitamin D. Furthermore, exploratory multivariate linear regression models will be constructed to determine relationships between vitamin D status and vascular function parameters (blood pressure, RHI) before and after adjustment for age and BMI.

Condition or disease Intervention/treatment Phase
Elevated Blood Pressure Endothelial Dysfunction Dietary Supplement: 2,000 International Units (IU)of vitamin D3 Not Applicable

  Show Detailed Description

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 27 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Prevention
Official Title: Effectiveness of Vitamin D Supplementation on Reducing Blood Pressure and Improving Endothelial Function of Pre-menopausal African American Women
Study Start Date : July 2015
Actual Primary Completion Date : May 2017
Actual Study Completion Date : May 2017

Resource links provided by the National Library of Medicine

Drug Information available for: Vitamin D

Arm Intervention/treatment
Experimental: Intervention
2,000 IU of vitamin D given to African American women for 10 weeks
Dietary Supplement: 2,000 International Units (IU)of vitamin D3
2,000 IU vitamin D taken daily for 10 weeks

Primary Outcome Measures :
  1. Effectiveness of vitamin D supplementation on reducing blood pressure [ Time Frame: 10 weeks ]
    Changes in blood pressure will be measured following vitamin D supplementation for 10 weeks in African American healthy pre-menopausal women

Secondary Outcome Measures :
  1. Effectvieness of vitamin d supplementation on improving endothelial function [ Time Frame: 10 weeks ]
    Changes of endothelial function will be measured by pulse amplitude tonometry fingertip plethysmography

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy pre-menomausal African American women

Exclusion Criteria:

  • History of elevated blood pressure >140/90 mm Hg
  • Pregnant or planning to become pregnant in the next three months
  • Lactating
  • Known Crohn's
  • Inflammatory bowel disease
  • Previous bowel resections
  • Bariatric surgeries, or psoriasis
  • Artificial or long fingernails they do not want to cut for testing
  • Regularly taking medications that might affect endothelial function such as anti-inflammatory medications, statins, anti-hypertensive medication, daily aspirin, non-SSRI psychotropic medication, and dietary supplements including vitamin D supplements

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): NCT02513823

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United States, Texas
Methodist Hospital
Houston, Texas, United States, 77030
Sponsors and Collaborators
Texas Woman's University
The Methodist Hospital System
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Principal Investigator: Carolyn Moore, PHD, RD, LD Methodist Hosptial

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Responsible Party: Carolyn Moore, Associate Professor, Texas Woman's University Identifier: NCT02513823     History of Changes
Other Study ID Numbers: 11089
First Posted: August 3, 2015    Key Record Dates
Last Update Posted: May 9, 2017
Last Verified: May 2017
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

Keywords provided by Carolyn Moore, Texas Woman's University:
blood pressure
vitamin D

Additional relevant MeSH terms:
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Vitamin D
Vascular Diseases
Cardiovascular Diseases
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents
Calcium-Regulating Hormones and Agents