Diabetes and Heart Disease Risk in Blacks

April 18, 2024 updated by: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

It is unknown if obesity contributes to the development of heart disease in African American men and women.

This study was created to determine whether there is a relationship between sex and body size and the incidence of heart disease in African American men and women. Researchers will attempt to associate obesity with the presence of heart disease risk factors. Risk factors that will be studied include; total body fat, body fat distribution, fat content of the blood (triglyceride concentration, low density lipoproteins [LDL], and high density lipoproteins [HDL]), how fast fat is removed from the blood, and how well insulin works in the body.

Scientific studies have shown that obesity and increased levels of fat content in the blood are important risk factors for heart disease in Caucasian women. However, similar studies in African American women have failed to show the same correlation. In fact, it appears that African American women in all three body weight groupings, nonobese, overweight, and obese experience high death rates due to heart disease. In addition, prior research has shown that obese African American men tend to have elevated levels of fat in the blood while African American women have normal blood fat levels. Therefore, if high levels of triglycerides (fat found in the blood) are not seen in non-diabetic obese African American women, it cannot be considered a risk factor in this population. This suggests that studies conducted on Caucasian women may not provide insight into heart disease risk factors in African American women.

The study will take 2000 healthy non-diabetic African American men and women (ages 18-70) and body mass index 3 subgroups; nonobese, overweight and obese. Diabetes undeniably increases the risk of heart disease. Therefore patients suffering from diabetes will not be included in the study. Candidates for the study will undergo a series of tests and examinations over 2 outpatient visits. Subjects will have body fat analyses, resting energy expenditure measurements, an EKG (electrocardiogram), and specific blood tests.

Researchers believe this study will provide significant insight into the causes of obesity and heart disease in African Americans....

Study Overview

Status

Recruiting

Conditions

Detailed Description

This study is designed to investigate in blacks the relationship of risk for diabetes and heart disease from obesity plasma glucose and triglyceride concentrations and the triglyceride related risk factors of small dense low density lipoprotein (LDL), high density lipoprotein (HDL) and central obesity.

The Framingham Study demonstrated that obesity and elevated glucose and triglyceride levels are important risk factors for coronary artery disease in white women. However, studies that have had significant participation of black women such as the Charleston Heart Study, failed to show a relationship of obesity or triglyceride to coronary artery disease mortality in black women. In fact, black women independent of body weight or triglyceride levels experience high mortality from coronary artery disease. Our earlier research has demonstrated that obese black men have elevated triglyceride levels but obese black women have normal triglyceride levels. Consequently if elevated triglyceride levels do not occur in obese nondiabetic black women, then elevated triglyceride levels may not represent a major cardiovascular risk for black women.

The study, Diabetes and Heart Disease Risk in Blacks, is designed to determine the role of obesity, glucose and triglyceride on risk for heart disease in blacks. For this study of blacks, we will study 2 groups, African Americans and Black Africans living in the United States. African Americans must self-identify as African American, be born in the United States and have parents who self-identify as African American and were born in the United States. The second group will be blacks living in the United States but were born in Africa and whose parents were born in Africa.

We will recruit 2000 healthy, non-diabetic individuals (), age range 18- 70, and body mass index (3 subgroups: nonobese, overweight and obese). In 2 outpatient visits to the Clinical Center, participants will have body fat analyses, an electrocardiogram, an oral glucose tolerance test, questionnaires about sleep, stress, discrimination, resilience, etc. and an intravenous glucose tolerance test or a beverage tolerance test. This study has the potential to provide significant insight and lead to the development of programs that help

decrease diabetes and cardiovascular risk in blacks.

Study Type

Observational

Enrollment (Estimated)

2000

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • United States
    • Maryland
      • Bethesda, Maryland, United States, 20892
        • Recruiting
        • National Institutes of Health Clinical Center
        • Contact:
          • For more information at the NIH Clinical Center contact Office of Patient Recruitment (OPR)
          • Phone Number: TTY dial 711 800-411-1222
          • Email: ccopr@nih.gov

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

Healthy volunteers of African descent,specifically African-born blacks and African Americans, recruited from the local area by flyer, newspaper advertisements, word of mouth and study personnel describing the study at community events.

Description

  • IINCLUSION AND EXCLUSION CRITERIA

CRITERIA FOR INCLUSION:

Ethnicity: Black

This is a study of adult African Americans and Blacks that were born in Africa but are now living in the United States. As African American people are multi-ethnic, we will in this initial investigation, study two different groups of African American. To enroll participants must self-identify as African Americans and be born in the United States, with American born parents or be born in Africa with African born parents. In both groups we will study sex differences in the role of obesity and TG levels on cardiovascular disease. In the future, we plan to expand the study to include other groups which self-identify as African Americans (i.e.AfroCarribeans and Hispanic blacks).

Only blacks are included in this study because the focus of this study is on gender differences in blacks in risk factors for CAD, specifically obesity, TG levels and TG related CAD risk factors. Unlike Caucasian women, premenopausal black women do not appear to be as protected from heart disease as a result of their gender. One model to study this apparent decrease in gender

related cardioprotection in black women is to compare black men to black women. An alternative model would be to compare black women to Caucasian women. However, since the primary focus of this work is on gender differences rather than racial differences comparing black women to men is a superior model. Other racial groups do not share the loss of gender-related cardioprotection found in blacks, and have been excluded. Further the advantage of comparing black men and women is that this comparison provides a better control of dietary, cultural and genetic factors.

Age: The age range of the participants will be between 18 and 70 years. As stated in the original protocol on page 14: Future investigations are planned which will involve similar comparisons between premenopausal and postmenopausal black women and between whites and blacks. To investigate risk for glucose intolerance, diabetes and cardiovascular risk factors, it is no longer sufficient to maintain the age range between 18 and 50 years. We need to expand to an age range with an increased prevalence of these risk factors.

Medical History: To participate in the study subjects should identify themselves as healthy. This is important so the broadest possible sample of people will enroll. The fact that people are healthy will be confirmed by the history, physical and laboratory tests done as part of the screening visit. People with established coronary artery as evidenced by history of myocardial infarction, coronary artery bypass surgery or PTCA will be allowed to participate if they are not currently having angina.

CRITERIA FOR EXCLUSION:

Black Ethnicity other than American or African.

As stated in the inclusion criteria black people are a multi-ethnic group. In this initial investigation we are focusing on African Americans who are American born and Africans living in the United States who are African born. In the future, we will expand the study to include other groups of blacks such as individuals of Afro-Caribbean and Hispanic blacks.

Medications: People who take medications that are known to alter the parameters which are under investigation in this study will be excluded. People taking medications to treat hyperlipidemia will be included but analyses will be adjusted to take this into account. Subjects on thyroid hormone replacement will be included if their TSH is normal.

Diabetes: Because diabetes affects insulin sensitivity and TG levels all people with diabetes even if the diabetes is controlled with diet alone will not be enrolled in the study.

Pregnant or Breastfeeding: Women who are pregnant, breastfeeding, or have an infant that is less than four months of age will be excluded. This is because the physiologic changes associated with pregnancy, breastfeeding or recent childbirth affect the parameters under study.

Menstrual History: Now that postmenopausal women are included, menstrual history will be taken but women with irregular menses and hysterectomy will not be excluded. Women between the ages of 40 and 55 years will have FSH checked for proper characterization. Women 56 years of age and older will be assumed to be postmenopausal. However, women on any type of injectable hormonal contraception will be excluded because hormonal contraception affects both TG levels and glucose metabolism.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Cross-Sectional

Cohorts and Interventions

Group / Cohort
Healthy volunteers
Healthy adult African Americans born in the United States, with American born parents or born in Africa with African born parents.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Diabetes and Heart Disease Risk
Time Frame: By Subject
Glucose Tolerance Status Lipid Profile Sickle Cell Trait Status Glucose 6 Phosphate Dehydrogenase Activity
By Subject

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

  • Principal Investigator: Anne E Sumner, M.D., National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 21, 1998

Study Registration Dates

First Submitted

November 3, 1999

First Submitted That Met QC Criteria

November 3, 1999

First Posted (Estimated)

November 4, 1999

Study Record Updates

Last Update Posted (Actual)

April 19, 2024

Last Update Submitted That Met QC Criteria

April 18, 2024

Last Verified

February 15, 2024

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 990002
  • 99-DK-0002

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

.Undetermined at this time

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Clinical Trials on Cardiovascular Diseases

Search Similar Trials

Sponsors and Collaborators

Medical Conditions

Drug Interventions

CROs by country

CROs in Uganda

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

3
Subscribe