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Protocol Details

Diabetes and Heart Disease Risk in Blacks

This study is currently recruiting participants.

Summary | Eligibility | Citations | Contacts

Summary

Number

99-DK-0002

Sponsoring Institute

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

Recruitment Detail

Type: Participants currently recruited/enrolled
Gender: Male & Female
Min Age: 18 Years
Max Age: 70 Years

Referral Letter Required

No

Population Exclusion(s)

American Indian or Alaskan Native;
Asian;
White;
Hispanic or Latino;
Native Hawaiian/Pacific Islander;
Children

Special Instructions

Currently Not Provided

Keywords

Healthy Volunteers;
Health Disparities;
Diabetes;
Cardiovascular Disease

Recruitment Keyword(s)

None

Condition(s)

Cardiovascular Diseases;
Diabetes;
Obesity;
Hypertension

Investigational Drug(s)

None

Investigational Device(s)

None

Intervention(s)

None

Supporting Site

National Institute of Diabetes and Digestive and Kidney Diseases

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.

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Eligibility

INCLUSION CRITERIA:

Ethnicity: Black

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).

Age: The age range of the participants will be between 18 and 70 years.

Medical History: To participate in the study subjects should identify themselves as healthy.

EXCLUSION CRITERIA:

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 African American groups 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: 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.


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Citations:

Utumatwishima JN, Chung ST, Bentley AR, Udahogora M, Sumner AE. Reversing the tide - diagnosis and prevention of T2DM in populations of African descent. Nat Rev Endocrinol. 2018 Jan;14(1):45-56. doi: 10.1038/nrendo.2017.127. Epub 2017 Oct 23.

Kabakambira JD, Baker RL Jr, Briker SM, Courville AB, Mabundo LS, DuBose CW, Chung ST, Eckel RH, Sumner AE. Do current guidelines for waist circumference apply to black Africans? Prediction of insulin resistance by waist circumference among Africans living in America. BMJ Glob Health. 2018 Oct 15;3(5):e001057. doi: 10.1136/bmjgh-2018-001057. eCollection 2018.

Briker SM, Aduwo JY, Mugeni R, Horlyck-Romanovsky MF, DuBose CW, Mabundo LS, Hormenu T, Chung ST, Ha J, Sherman A, Sumner AE. A1C Underperforms as a Diagnostic Test in Africans Even in the Absence of Nutritional Deficiencies, Anemia and Hemoglobinopathies: Insight From the Africans in America Study. Front Endocrinol (Lausanne). 2019 Aug 7;10:533. doi: 10.3389/fendo.2019.00533. eCollection 2019.

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Contacts:

Principal Investigator

Referral Contact

For more information:

Anne E. Sumner, M.D.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
BG 10-CRC RM 6-5950
10 CENTER DR
BETHESDA MD 20814
(301) 402-7119
anne.sumner@nih.gov

Anne E. Sumner, M.D.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
BG 10-CRC RM 6-5950
10 CENTER DR
BETHESDA MD 20814
(301) 402-7119
anne.sumner@nih.gov

Office of Patient Recruitment
National Institutes of Health Clinical Center (CC)
Building 61, 10 Cloister Court
Bethesda, Maryland 20892
Toll Free: 1-800-411-1222
Local Phone: 301-451-4383
TTY: 1-866-411-1010
PRPL@cc.nih.gov

Clinical Trials Number:

NCT00001853

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