Genomics, Environmental Factors and Social Determinants of Cardiovascular Disease in African Americans Study (GENE-FORECAST): Sodium Intervention Trial (SIT)

Genomics, Environmental Factors and Social Determinants of Cardiovascular Disease in African-Americans Study(GENE-FORECAST): Sodium Intervention Trial (SIT)/GENE-FORECAST SIT

Background:

Hypertension is a risk factor for heart disease. Low-sodium diets rich in fruits, vegetables, and other healthy foods are a good way to reduce blood pressure in people with hypertension. Researchers want to learn more about why African Americans seem to have the greatest benefit from certain dietary interventions.

Objective:

To better understand the body's response to adding more salt to the diet.

Eligibility:

U.S.-born African American adults ages 21 to 65 who are in good general health and took part in the GENE-FORECAST.

Design:

Participants will be screened with a medical history and physical exam. If needed, they will take a pregnancy test. These tests will be repeated during the study.

Each day for 2 weeks, participants will take 3 capsules that contain either placebo or salt. Then they will take no pills for 3 weeks. Then they will take placebo or salt capsules for 2 more weeks.

Participants will talk about the foods and drinks they have consumed over the past 24 hours. They will take a survey about their physical activity and sleep.

Participants will complete taste tasks to obtain their responses to sweetness or saltiness. Sucrose and salt detection thresholds and preferences will be assessed.

Participants will give blood and urine samples. Saliva samples will be collected from their mouth by passive drool or by spitting into a sterile tube. Skin samples will be collected from behind their ears and the inner part of their elbow, using sterile swabs. Participants will get kits to collect stool samples at home.

Participants will have 4 study visits over 7 weeks.

Study Overview

• Status: Completed
• Conditions: Cardiovascular Disease
• Intervention / Treatment: Other: Placebo; Other: Sodium Chloride

Detailed Description

The objective of this study is to implement a sodium intervention investigation to assess the effect of increased dietary sodium intake on changes in blood pressure, vascular function, microbiome, whole blood epigenome, whole blood and urine transcriptome as outcome measures. The study design will include a double-blind, cross-over treatment/placebo trial among African Americans GENE-FORECAST participants with normal blood pressure and will last 7 weeks. It is hypothesized that exposure to increased dietary sodium will affect blood pressure, whole blood epigenome, whole blood and urine transcriptome, vascular function, microbiome and blood pressure.

• Study Type: Interventional
• Enrollment (Actual): 36
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Bethesda, Maryland, United States, 20892
      • National Institutes of Health Clinical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

• INCLUSION CRITERIA:

African American men and women who are former GENE-FORECAST participants between 21 and 65 years of age. This criterion is inclusive of self-identified AA of both Hispanic, Latino and non-Hispanic, Latino ethnicities. Normotensive participants with systolic blood pressure (SBP) <140 mm Hg and diastolic blood pressure (DBP) <90 mm Hg and the absence of a history of prior diagnosis of hypertension.

-Willingness and ability to participate in study procedures.

EXCLUSION CRITERIA:

• Individuals who are pregnant or breast-feeding.
• Individuals with high blood pressure or a history of hypertension.
• Individuals with a history of myocardial infarction, stroke, heart failure, diabetes, chronic liver or kidney diseases.
• Individuals who are taking antihypertensive, antidepressants, antidiabetic and antibiotic medications.
• Individuals currently participating in another NIH protocol.
• Individuals unable to provide informed consent.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cohort 1: Sodium Chloride then Placebo; Participant will take Sodium Chloride at 3 pills per day for a total of 3 grams for two weeks, followed by a wash-out period for three-weeks, then ending with a cross-over to the Placebo at 3 pills per day for a total of 3 grams for two weeks.	Other: Placebo; placebo capsules; Other: Sodium Chloride; It is well established that increased dietary sodium can predispose to an increase in blood pressure; particularly in salt-sensitive individuals. Seeking to test the hypothesis that changes in dietary sodium intake are sufficient to influence the composition of the gut microbiome in association with sodium-induced changes in vascular function, epigenome, transcriptome and blood pressure in African Americans.; Other Names: salt treatment
Experimental: Cohort 2: Placebo then Sodium Chloride; Participant will take Placebo at 3 pills per day for a total of 3 grams for two weeks, followed by a wash-out period for three-weeks, then ending with a cross-over to the Sodium Chloride at 3 pills per day for a total of 3 grams for two weeks.	Other: Placebo; placebo capsules; Other: Sodium Chloride; It is well established that increased dietary sodium can predispose to an increase in blood pressure; particularly in salt-sensitive individuals. Seeking to test the hypothesis that changes in dietary sodium intake are sufficient to influence the composition of the gut microbiome in association with sodium-induced changes in vascular function, epigenome, transcriptome and blood pressure in African Americans.; Other Names: salt treatment

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mean Change in Vascular Function Measured by Pulse Wave Velocity	Mean change in vascular function was measured by Pulse Wave Velocity (PWV) using the SphygmoCor XCEL. PWV was determined by recording the pulse waves of the carotid and femoral arteries and calculating the ratio of the distance between the pulse measuring sites to the time delay between the carotid and femoral pulse waves. The distance was measured with a non-stretchable tape from the suprasternal notch to the carotid site and from the suprasternal notch to the femoral site. The former distance was subtracted from the latter and used in the calculation of PWV. High PWV is directly associated with increased arterial stiffness, reflecting reduced elasticity of the arterial walls.	Baseline, Week 2, Week 5 and Week 7

Collaborators and Investigators

• Sponsor: National Heart, Lung, and Blood Institute (NHLBI)
• Collaborators: National Human Genome Research Institute (NHGRI)
• Investigators: Principal Investigator: Amadou Gaye, PhD, National Human Genome Research Institute (NHGRI)

Publications and helpful links

Helpful Links

• NIH Clinical Center Detailed Web Page

Study record dates

Study Major Dates

• Study Start (Actual): January 22, 2021
• Primary Completion (Actual): June 30, 2022
• Study Completion (Actual): July 8, 2022

Study Registration Dates

• First Submitted: January 20, 2021
• First Submitted That Met QC Criteria: January 21, 2021
• First Posted (Actual): January 22, 2021

Study Record Updates

• Last Update Posted (Actual): April 27, 2025
• Last Update Submitted That Met QC Criteria: April 9, 2025
• Last Verified: July 23, 2024

More Information

Terms related to this study

• Keywords: Cardiovascular Disease; African American
• Additional Relevant MeSH Terms: Cardiovascular Diseases
• Other Study ID Numbers: 10000070; 000070-H

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Pending

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No