Psychophysiology of Cardiovascular Reactivity
Condition: Cardiovascular Diseases; Heart Diseases; Hypertension
MeSH terms: Cardiovascular Diseases; Heart Diseases
Study type: Observational

Summary: 
      To determine why Black Americans have a higher prevalence of hypertension than whites by
      examining the interactions of psychosocial stressors and suppressed hostility with genetic or
      constitutional factors.
    

Detailed description: 
      BACKGROUND:

      Blacks in the United States have a much greater prevalence of essential hypertension than
      whites. The prevalence of hypertension for adults aged 18-74 has been estimated at 15.7
      percent for white women, 18.5 percent for white men, 27.8 percent for Black men and 28.6
      percent for Black women. Among adults who underwent screening for the Hypertension Detection
      and Follow-up Program, 36.2 percent of Black males and 38.2 percent of Black females either
      had diastolic blood pressures at least as high as 95 mmHg or were taking antihypertensive
      medications. The Black-white ratio for the prevalence of hypertension in this survey was
      approximately 2. Reportedly, the prevalence of hypertension among inner city Blacks may be as
      high as 50 percent. The exact causes of the disparity in hypertension prevalence between
      Blacks and whites are unknown, but genetic predisposition, psychosocial stress, and
      life-style factors such as high sodium ingestion and obesity have been implicated. None of
      these factors alone appears sufficient to account for the difference in the prevalence of
      hypertension between Blacks and whites, suggesting that multiple factors and/or interactions
      between factors may be involved.

      DESIGN NARRATIVE:

      The study is supported by a program project grant and thus includes many subprojects.
      Projects 1A through 1C were supported beginning in 1986. Project 1A examined the effects of
      cardiovascular and hormonal responses to standardized laboratory challenges as a function of
      race, sex, age, and normal blood pressure versus borderline hypertension. The subjects were
      classified according to four categories: Black or white race; male or female sex; normal or
      raised blood pressure; and ages 25-39 or 40-54, giving a total of 16 cells with 15 subjects
      in each. The subjects were given a physical examination, electrocardiogram, blood screening
      test as well as a battery of special tests including a Structured Interview for Type A
      behavior pattern, playing a video game, a test designed to elicit anger, and exercise on a
      bicycle ergometer. During these tasks subjects were monitored for heart rate and blood
      pressure, and blood was sampled for plasma catecholamines, renin, cortisol, aldosterone, and
      vasopressin. Various psychological tests were administered including the Cook-Medley
      hostility scale, the Life Orientation test, a job stress scale, the John Henryism Active
      Coping Scale and others. Urine samples were collected for electrolyte and catecholamine
      excretion and ambulatory blood pressure was monitored on a work day and on a non-work day.

      Project IB examined the effects of acute sodium loading and depletion on cardiovascular and
      hormonal reactivity as a function of race and sex. Normotensive subjects were classified
      according to two categories: Black or white race; male or female sex, with four cells of 15
      subjects each. After the initial medical examination, subjects were seen three times at
      intervals of two weeks. Before each visit three overnight urine collections were made for
      electrolyte excretion evaluation. On these three visits subjects were randomized to either a
      control day, a sodium loading day, or sodium depletion day. On each of these days subjects
      were given three reactivity tests including the video game, exercise test, and
      speech-stressor task. The same psychological tests as in Project 1A were given on the
      mornings of the three testing days.

      Project 1C was a five-year follow-up of 80 subjects in the Study of Biobehavioral Factors
      Affecting Hypertension in Blacks. Subjects had a routine history and physical exam and were
      then given the Type A Interview, a video game, and an exercise task. Subjects also provided
      three overnight urine samples.

      Two substudies were also conducted. The goal of substudy 1 was to determine what psychosocial
      factors predicted cardiovascular responding at work in Black and white women. Black and white
      normotensive nurses between the ages of 20-45 years served as subjects. Substudy 2 examined
      the affective and physiological responses of Black and white college students during
      challenge. Normotensive Black and white men and women were monitored for blood pressure and
      heart rate during rest and during three tasks including mirror star tracing, hand immersion
      cold pressor, and speech stressor.

      The program project was renewed in 1996. Subproject 7 addresses the the problem of modifying
      risk in youth with high blood pressure. The subproject compares adolescents with high versus
      normal blood pressure in terms of fasting insulin, oral glucose tolerance, adiposity, aerobic
      fitness, diet, cardiac mass, autonomic reactivity, psychosocial characteristics and family
      medical history. Subproject 7 renewed as Subproject 1 in FY 2001 examines the long-term
      effects of three intervention conditions: a three month self-management intervention; a six
      month augmented self-management skill acquisition intervention program; and usual care.
      Subproject 8 renewed as Subproject 2 in FY 2001 involves behavioral intervention in
      post-myocardial infarction patients receiving standard pharmacological treatment or standard
      pharmacological treatment plus behavioral treatment including stress management, dietary
      supervision, and self-directed exercise.
    

Sampling method: Non-Probability Sample