Hypertension in Families of African Origin

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00005444
Recruitment Status : Completed
First Posted : May 26, 2000
Last Update Posted : February 18, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To investigate familial patterns of hypertension and related cardiovascular (CV) risk factors in the United States and Nigeria.

Condition or disease
Cardiovascular Diseases Heart Diseases Hypertension

Detailed Description:


It has been known for many years that African Americans experience twofold higher rates of hypertension than do whites. The underlying biological mechanisms which lead to this differential are still not understood, however. Despite widespread speculation that persons of African descent are genetically susceptible to hypertension, few direct studies have been carried out. Rates of hypertension remain low in West Africa, and this study will provide a contrast between populations of similar genetic background in a low versus high risk environmental setting


A total of 240 families were identified from completed community surveys in Maywood, Illinois and Ibadan, Nigeria. Probands were ages 45-55 and equally divided between males and females. A minimum of five first-degree relatives were examined in each family to obtain information on the following variables: blood pressure (BP), obesity, urinary sodium and potassium, socioeconomic status and physical activity. In addition, plasma and DNA were collected and stored for future studies of relevant physiologic intermediate phenotypes and candidate genes for hypertension in the two contrasting populations. These data provided the basis for examining familial aggregation of blood pressure/hypertension and related CV risk factors. Three primary goals were addressed: 1) to determine whether the familial aggregation of blood pressure in Black populations was influenced by the overall distribution of environmental factors at the population level, by contrasting the distribution of familial correlations of blood pressure and the familial aggregation of hypertension, in Nigeria and the United States; to determine the significance of measured environmental correlates of blood pressure by comparing the magnitude of variance components for probands and relatives in each setting; and 3) to use path analysis to obtain estimates of genetic and cultural heritability of blood pressure, controlling for clustering environmental factors at the household level. Plasma and DNA samples collected in this study provided additional valuable resources for future molecular research.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

Study Type : Observational
Study Start Date : August 1995
Actual Study Completion Date : July 2001

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

Ages Eligible for Study:   up to 100 Years   (Child, Adult, Senior)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
No eligibility criteria

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00005444

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
OverallOfficial: Charles Rotimi Howard University

Publications: Identifier: NCT00005444     History of Changes
Other Study ID Numbers: 4373
R29HL052075 ( U.S. NIH Grant/Contract )
First Posted: May 26, 2000    Key Record Dates
Last Update Posted: February 18, 2016
Last Verified: July 2004

Additional relevant MeSH terms:
Cardiovascular Diseases
Heart Diseases
Vascular Diseases