Diabetes and Heart Disease Risk in Blacks

Launched by NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES (NIDDK) · Nov 3, 1999

Keywords

ClinConnect Summary

This clinical trial is studying how obesity may affect the risk of heart disease in African American men and women. Researchers want to understand if there are differences between the sexes and how body size relates to heart disease risk factors like body fat, cholesterol levels, and how well insulin works in the body. While obesity is known to increase heart disease risk in Caucasian women, similar findings for African American women are not clear, prompting this important research.

To participate, individuals must be healthy, self-identify as African American, and be between 18 and 70 years old. The study will include 2,000 participants who fall into three weight categories: non-obese, overweight, and obese. Those with diabetes, which can complicate the results, will not be included. Participants will go through several tests at two outpatient visits, including body fat measurements and blood tests. This study aims to provide valuable insights into how obesity and heart disease are connected in the African American community, which could lead to better prevention and treatment strategies in the future.

Gender

ALL

Eligibility criteria

• • 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.