316

Orthostatic Blood Pressure Responses as a Function of Ethnicity and Socioeconomic Status: The ARIC Study

RODNEY CLARK,

a,b

HERMAN A. TYROLER,

c

AND GERARDO HEISS

c

b

Department of Psychology, Wayne State University, 71 West Warren, Detroit, Michigan 48202, USA

c

Department of Epidemiology, University of North Carolina at Chapel Hill, School of Public Health, Chapel Hill, North Carolina 27514, USA

According to a recent definition devised by the Joint National Committee on HighBlood Pressure, approximately 51 million Americans, 17 years of age and older,meet diagnostic criteria for hypertension.

1

One controversial line of research aimedat delineating the putative causes of hypertension has examined the relationshipbetween cardiovascular responses to standardized stressors (e.g., orthostasis) andcardiovascular outcomes.

2–5

Research also suggests that cardiovascular responses tothese stressors vary as a function of ethnicity

6

and socioeconomic status.

7

This study examined the effects of ethnicity and education on orthostatic bloodpressure responses in a normotensive sample of participants free of clinical cardio-vascular disease and diabetes (

n

=

6,412). Average supine–standing blood pressuremeasurements were calculated and were used for stratified and logistic analyses.Prevalence odds ratios (POR) and 95% confidence intervals (CI) were calculated asthe measures of effect in the multivariate logistic analyses. Sitting systolic and dias-tolic blood pressure levels were associated with the magnitude of orthostatic bloodpressure responses. African-Americans were more likely to exhibit exaggerated sys-tolic (POR

=

1.22, CI

=

1.08, 1.38) and diastolic (POR

=

1.32, CI

=

1.15, 1.50) bloodpressure responses to orthostasis. Relative to participants with 12 years of education,participants with less than 12 years of education were more likely to have exagger-ated increases or exaggerated decreases in systolic blood pressure on standing (12%and 20%, respectively). A significant interaction between ethnicity and educationwas not observed in these data. There was no evidence of modification of ethnicityand education effects by any of the covariates.

The observed orthostatic blood pressure differences may be attributable to differ-ential exposures to chronic psychosocial stressors in African-Americans and thoseof low educational achievement.

8,9

Future studies might extend the finding here by(1) obtaining individual information on environmental factors like perceived racism,chronic stress, and job strain to quantify psychosocial stress exposure; (2) examiningthe possible mediating effects of psychosocial factors like John Henryism, life style

a

Address for correspondence: Rodney Clark, Department of Psychology, Wayne State Uni-versity, 71 West Warren, Detroit, MI 48202, USA. 313-577-7640 (voice); 313-577-7636 (fax).

e-mail: rclark@sun.science.wayne.edu

317CLARK

et al.

: THE ARIC STUDY

incongruity, and anger-coping styles, and (3) investigating the efficacy of psychoso-cial stress exposure as a predictor of subsequent hypertension development.

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