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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
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.
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.
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
American Journal of Cardiology, 1996 Feb 1, 77(4):270-4.
Pub type: CLINICAL TRIAL; CONTROLLED CLINICAL TRIAL; JOURNAL ARTICLE.
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.
Pub type: CLINICAL TRIAL; JOURNAL ARTICLE; RANDOMIZED CONTROLLED TRIAL.
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.
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.