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Completed

NCT Number: NCT04717336

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

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Key information

Conditions

Cardiovascular Disease Cardiovascular Diseases

Age range

21 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

National Institutes of Health Clinical Center

Bethesda, Maryland, 20892, United States

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

  • 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.

Treatment and study plan

Sodium Chloride

Other

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

Placebo

Other

placebo capsules

Primary outcomes

  1. Mean Change in Vascular Function Measured by Pulse Wave Velocity

    Time frame: Baseline, Week 2, Week 5 and Week 7

    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.

Sponsors and collaborators

Lead sponsor

National Heart, Lung, and Blood Institute (NHLBI)

Nih

Collaborators

  • National Human Genome Research Institute (NHGRI)

Registry information

Official study title

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

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
Jan 22, 2021
Registry last updated
Apr 27, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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