Divergence of Blood Pressure By Race in Adolescent Girls

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: NCT00005470
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 continue examinations of 670 girls enrolled in the National Growth and Health Study (NGHS) for four more years, adding measurements of total peripheral resistance, cardiac output, DEXA scans for fat-free mass and fat mass, left ventricular mass and geometry, circulating blood volume, whole blood viscosity, and left ventricular contractility.

Condition or disease
Cardiovascular Diseases Heart Diseases Hypertension Obesity

Detailed Description:


African-American women have a substantially higher prevalence of hypertension and suffer greater morbidity and mortality due to blood pressure elevation than white-American women. Much of this ethnic difference in blood pressure is due to increased obesity in African-American women. In contrast, young African-American and white-American girls have similar levels of obesity and blood pressure. The hemodynamic changes that occur with developing obesity and result in this ethnic difference in blood pressure have not been well characterized. Cross-sectional studies of adolescents have shown that despite similar blood pressure levels, African-Americans have higher total peripheral resistance while whites have higher cardiac output. Cross-sectional studies of adults show that obesity is associated with elevation of cardiac output. If such an obesity-related increase in cardiac output is superimposed on the underlying elevation of total peripheral resistance in African-American girls, these hemodynamic factors could be responsible for the developing ethnic divergence in blood pressure seen in late adolescence as African-American girls develop an increasing prevalence and severity of obesity.

This investigation will provide important new knowledge regarding the longitudinal changes and interrelationships among the potential hemodynamic factors which define the association between developing obesity and blood pressure elevation. In the clinical setting where obesity is very difficult to prevent or treat, it is important to understand the mechanisms by which obesity results in elevated blood pressure. The results of this cohort study will provide the basis for rational and specific clinical strategies to interrupt the pathophysiologic process by which obesity leads to hypertension and places African-American women at particularly increased risk for cardiovascular disease morbidity and mortality.

The NGHS was initiated by the NHLBI in 1985 as a contract-supported program to determine if the Black-white differences in the development of obesity in 2,379 pubescent females were due to differences in psychosocial, socioeconomic and other environmental factors. The study also sought to determine whether differences in the development of obesity led to Black-white differences in other coronary heart disease risk factors, such as blood pressure and serum lipids. The study has been renewed twice, the last time as an investigator-initiated study. See the National Growth and Health Study for the complete write-up.


The ancillary study is a prospective cohort study of 355 African-American and 315 white-American females from the NHLBl Growth and Health Study as these women progress from age 18-19 years to age 21-22 years. The study includes yearly measurement of anthropometrics, blood pressure, and echocardiographic determination of cardiac output and total peripheral resistance. In addition, factors which may relate to changes in cardiac output and total peripheral resistance, such as circulating blood volume (left ventricular end-diastolic volume), heart rate, left ventricular contractility, whole blood viscosity, and left ventricular mass and geometry are measured.

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 : September 1996
Actual Study Completion Date : August 2002

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

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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): NCT00005470

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
OverallOfficial: Stephen Daniels Children's Hospital & Medical Center