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[IP] Caffeine and hypertension: Melvyl Medline search

To all interested,

Here's a bit of what I found in the current set of Melvyl Medline
(1993-present) combining the two MeSH (Medical Subject Headings) Caffeine
and Hypertension.

email @ redacted

 1. (MEDLINE result)
    Lovallo WR; Al'Absi M; Blick K; Whitsett TL; Wilson MF.
      Stress-like adrenocorticotropin responses to caffeine in young healthy
    Pharmacology, Biochemistry and Behavior, 1996 Nov, 55(3):365-9.
      Pub type:  Clinical Trial; Journal Article; Randomized Controlled Trial.
        (UI:  97109697)

Abstract: The effects of oral caffeine (3.3 mg/kg, equivalent to 2-3 cups of
    coffee) on plasma adrenocorticotropin (ACTH) and cortisol (CORT) were
    tested in 47 healthy young men at rest in a double-blind,
    placebo-controlled, crossover study. Following caffeine, ACTH was
    significantly elevated at all times from 30 min to 180 min, and CORT was
    elevated from 60 min to 120 min (Fs > or = 8.4, ps < 0.01). Peak increases
    relative to placebo were: ACTH, 33% (+5.2 pg/ml) and CORT, 30% (+2.7
    micrograms/dl) at 60 min postcaffeine. The results suggest that caffeine
    can activate important components of the pituitary-adrenocortical response
    in humans during the resting state. Caffeine's known ability to increase
    CORT production appears at least partly due to an increase in ACTH release
    at the pituitary.

 2. (MEDLINE result)
    Palatini P; Canali C; Graniero GR; Rossi G; de Toni R; Santonastaso M; dal
        Follo M; Zanata G; Ferrarese E; Mormino P; et al.
      Relationship of plasma renin activity with caffeine intake and physical
      training in mild hypertensive men. HARVEST Study Group.
    European Journal of Epidemiology, 1996 Oct, 12(5):485-91.
        (UI:  97061280)

Abstract: To study the relationship between plasma renin activity (PRA) and
    coffee consumption, cigarette smoking, alcohol intake and physical activity
    habits. Setting: The multicentre HARVEST trial, involving 17 Hospital
    Centres in Northeast Italy. Subjects: 351 borderline to mild hypertensive
    men (mean age +/- SEM 22.7 +/- 0.47 years), never treated for hypertension.
    Interventions: Office and 24-hour blood pressure measurement, supine and
    standing PRA levels, and urinary catecholamines output. Main outcome
    measures: PRA levels according to coffee intake and physical activity
    status. Results: Coffee intake showed a major effect on PRA. Supine PRA
    levels were 40% higher in the subjects abstaining from coffee (n = 94) than
    in the coffee drinkers and was similar in the moderate (n = 223) and heavy
    (n = 34) drinkers. A weaker negative association was found between coffee
    use and PRA on standing. Office and whole-day blood pressure and heart
    rate, and urinary catecholamines did not differ according to coffee intake.
    Supine PRA was lower in the subjects performing regular physical activity
    than in the inactive subjects. Office and whole-day diastolic blood
    pressure and heart rate, and urinary norepinephrine were lower in the
    active than in the sedentary men. No relationship was found between PRA
    measured either in the supine or the upright posture and tobacco or alcohol
    use. In a multiple linear regression model supine PRA was negatively
    correlated with age, coffee consumption and physical activity habits.
    Conclusions: Chronic coffee intake and physical training showed an inverse
    relationship with PRA in mild hypertensive men, while tobacco and alcohol
    use were unrelated to PRA.

 3. (MEDLINE result)
    Pincomb GA; Lovallo WR; McKey BS; Sung BH; Passey RB; Everson SA; Wilson
      Acute blood pressure elevations with caffeine in men with borderline
      systemic hypertension.
    American Journal of Cardiology, 1996 Feb 1, 77(4):270-4.
        (UI:  96190269)

Abstract: Whether the vasoconstrictive actions of caffeine are enhanced in
    hypertensive persons has not been demonstrated. Thus, caffeine (3.3 mg/kg)
    versus placebo was tested in 48 healthy men (aged 20 to 35 years) selected
    after screening on 2 separate occasions. Borderline hypertensive men (n =
    24) were selected with screening systolic blood pressure (BP) of 140 to 160
    mm Hg and/or diastolic BP 90 to 99 mm Hg. Low-risk controls (n = 24)
    reported no parental history of hypertension and had screening BP < 130/85
    mm Hg. Participants were then tested on 2 occasions after 12-hour
    abstinence from caffeine in each of 2 protocols; this required a total of 4
    laboratory visits. Caffeine-induced changes in diastolic BP were 2 to 3
    times larger in borderline subjects than in controls (+8.4 vs +3.8 mm Hg, p
    < 0.0001), and were attributable to larger changes in impedance-derived
    measures of systemic vascular resistance (+135 vs +45 dynes.s.cm-5, p <
    0.004). These findings were consistent and reached significance in both
    protocols. The percentage of borderline subjects in whom diastolic BP
    changes exceeded the median control response was 96%. Consequently, whereas
    all participants exhibited normotensive levels during the resting predrug
    baseline, 33% of borderline subjects achieved hypertensive BP levels after
    caffeine ingestion. Thus, in borderline hypertensive men, exaggerated
    responses to caffeine were: selective for diastolic BP, consistent with
    greater vasoconstriction, replicated in 2 protocols, and representative of
    nearly all borderline hypertensives. We suspect that the potential for
    caffeine to stabilize high resistance states in susceptible persons
    suggests that its use may facilitate their disease progression, as well as
    hinder accurate diagnosis and treatment.

 4. (MEDLINE result)
    Lovallo WR; al'Absi M; Pincomb GA; Everson SA; Sung BH; Passey RB; Wilson
      Caffeine and behavioral stress effects on blood pressure in borderline
      hypertensive Caucasian men.
    Health Psychology, 1996 Jan, 15(1):11-17.
        (UI:  96380523)

Abstract: Caffeine in dietary amounts raises blood pressure (BP), and its use
    increases during work stress; however, caffeine combined with behavioral
    stress has not been tested in borderline hypertensive (BH) men.
    Accordingly, this study tested a psychomotor stressor plus caffeine (3.3
    mg/kg, equivalent to 2-3 cups of coffee) using a double-blind, crossover
    design in 24 BH men (140/90 mmHg < or = BP < or = 160/95 mmHg) and 24
    controls (BP < or = 135/85 mmHg). BH men had modestly larger BP increases
    to the task and showed a greater combined effect of caffeine plus the task
    (+15/+11 mmHg) than controls (+10/+6 mmHg). BH men maintained response to
    the stressor in the face of an exaggerated BP response to caffeine,
    suggesting that use of caffeine during behavioral stress may elevate BP in
    BH individuals to a clinically meaningful degree.

 5. (MEDLINE result)
    Palmer JR; Rosenberg L; Rao RS; Shapiro S.
      Coffee consumption and myocardial infarction in women.
    American Journal of Epidemiology, 1995 Apr 15, 141(8):724-31.
        (UI:  95225271)

Abstract: Whether coffee consumption increases the risk of coronary heart
    disease has not yet been established. In a case-control study of nonfatal
    myocardial infarction among Massachusetts women aged 45-69 years in
    1986-1990, 858 cases with first infarctions were compared with 858
    community controls matched on age and town precinct. Detailed information
    on coffee drinking, cigarette smoking, and other factors was obtained by
    telephone interview. Relative risks (as estimated by odds ratios) and their
    95% confidence intervals were computed from multiple logistic regression
    analyses that controlled for smoking and other risk factors. The risk of
    myocardial infarction increased with increasing number of cups per day
    among both drinkers of any type of coffee and drinkers of
    caffeine-containing coffee only: tests for trend, p = 0.002 and p = 0.0004,
    respectively. For consumption of caffeine-containing coffee alone, the
    relative risk estimates for 5-6 cups, 7-9 cups, and 10 or more cups per day
    relative to less than 1 cup per day were 1.4 (95% confidence interval (CI)
    0.8-2.5), 2.1 (95% CI 0.9-4.9), and 2.5 (95% CI 1.0-6.5), respectively. No
    increase was observed for fewer than 5 cups per day. The positive
    association with heavy coffee drinking was present among nonsmokers as well
    as smokers. These findings and other recent studies suggest that heavy
    coffee consumption increases the risk of myocardial infarction.