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Genetics of Cardiovascular Reactivity in Black Youth

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: NCT00064675
Recruitment Status : Completed
First Posted : July 14, 2003
Last Update Posted : April 8, 2013
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
University of Tennessee

Brief Summary:
To evaluate individual differences in cardiovascular responses to acute stress in Black adolescents.

Condition or disease
Cardiovascular Diseases Heart Diseases Hypertension

Detailed Description:


The prevalence and severity of essential hypertension (EH) are greater among Black Americans than other ethnic groups in the U.S. Blacks are at increased risk for target organ damage from elevated blood pressure, including heart disease, stroke, and endstage renal failure. There are significant ethnic differences in cardiovascular reactivity (CVR) to stress, which is a risk factor for elevated blood pressure. Studies have shown that CVR to stress is stable over time, heritable, and predictive of future elevations in blood pressure and the development of essential hypertension. These properties make measures of CVR a valuable intermediate for genetic studies of hypertensive risk.


The genetic epidemiology study will test the hypothesis that individual differences in CVR to acute stress in Black youth are associated with well defined polymorphisms in candidate genes related to blood pressure including: 1) alpha- and beta-adrenergic receptor genes; 2) genes involved in catecholamine metabolism; 3) genes involved in endocrine function; 4) genes involved in the renin angiotensin system. By focusing on normotensive youth at risk for developing essential hypertension, the investigators hope to identify genes associated with the onset, rather than the sequelae, of hypertension. Moreover, given that CVR to acute stress is defined as a change in cardiovascular function evoked by an environmental manipulation of stress, the research is inherently a study of gene-environment interactions.

A total of 500 unrelated Black adolescents and young adults (equal numbers of males and females), 15-21 years of age will be studied. Buccal cell samples will be collected for DNA extraction from all subjects for genetic association analyses. Impedance cardiography and blood pressure monitoring will be used to assess components of CVR to stress during video game, mental arithmetic, cold pressor, and whole body cold exposure tasks, all of which have been utilized or developed in the laboratory. Various methods will be used to evaluate genetic associations with CVR to acute stress, including analyses of single nucleotide polymorphisms and haplotypes. Supplementary analyses will evaluate potential gene-gene interactions and additional gene-environment interactions involving chronic environmental stress.

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Study Type : Observational
Actual Enrollment : 500 participants
Observational Model: Cohort
Time Perspective: Cross-Sectional
Official Title: Genetics of Cardiovascular Reactivity in Black Youth
Study Start Date : July 2003
Actual Primary Completion Date : June 2008
Actual Study Completion Date : June 2008

Resource links provided by the National Library of Medicine

Primary Outcome Measures :
  1. genes associated with hyperreactivity [ Time Frame: done ]
    several genes associated with reactivity

Biospecimen Retention:   Samples With DNA
buccal specimens stored at Med Coll Wisconsin

Information from the National Library of Medicine

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Ages Eligible for Study:   15 Years to 21 Years   (Child, Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
500 African American youth
African American non-hypertensive, no chronic disease which would affect blood pressure

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): NCT00064675

Sponsors and Collaborators
University of Tennessee
National Heart, Lung, and Blood Institute (NHLBI)
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Principal Investigator: Bruce Alpert University of Tennessee Health Science Center

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Responsible Party: University of Tennessee Identifier: NCT00064675     History of Changes
Other Study ID Numbers: 1229
R01HL072375 ( U.S. NIH Grant/Contract )
R01HL068971-04 ( U.S. NIH Grant/Contract )
First Posted: July 14, 2003    Key Record Dates
Last Update Posted: April 8, 2013
Last Verified: April 2013

Additional relevant MeSH terms:
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Heart Diseases
Cardiovascular Diseases