Genetics of Cardiovascular Reactivity in Black Youth

Hypertension Clinical Trial

Official title:

Genetics of Cardiovascular Reactivity in Black Youth

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00064675
• Other study ID #: 1229
• Secondary ID: R01HL072375R01HL
• Status: Completed
• Phase: N/A
• First received: July 10, 2003
• Last updated: April 4, 2013
• Start date: July 2003
• Est. completion date: June 2008

Study information

• Verified date: April 2013
• Source: University of Tennessee
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Federal Government
• Study type: Observational

Clinical Trial Summary

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

Description:

BACKGROUND:

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.

DESIGN NARRATIVE:

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 500
• Est. completion date: June 2008
• Est. primary completion date: June 2008
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 15 Years to 21 Years
• Eligibility: African American non-hypertensive, no chronic disease which would affect blood pressure

Study Design

Observational Model: Cohort, Time Perspective: Cross-Sectional

Related Conditions & MeSH terms

• Cardiovascular Diseases
• Heart Diseases
• Hypertension

Locations

Country	Name	City	State
n/a

Sponsors (2)

Lead Sponsor	Collaborator
University of Tennessee	National Heart, Lung, and Blood Institute (NHLBI)

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	genes associated with hyperreactivity	several genes associated with reactivity	done	No