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Study Title and Description

Effects of acute administration of caffeine on vascular function.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
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Primary Publication Information
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TitleData
Title Effects of acute administration of caffeine on vascular function.
Author T Umemura,K Ueda,K Nishioka,T Hidaka,H Takemoto,S Nakamura,D Jitsuiki,J Soga,C Goto,K Chayama,M Yoshizumi,Y Higashi,
Country
Year 2006
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
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What is the objective of the study (as reported by the authors)? This study was designed to examine the effects of the acute administration of caffeine on systemic hemodynamics and endothelial function in humans by measuring forearm blood flow (FBF) responses to acetylcholine (ACh), an endothelium-dependent vasodilator, and to sodium nitroprusside (SNP), an endothelium-independent vasodilator.
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) The subjects were 20 young healthy men recruited from healthy volunteers. All were nonhabitual caffeine consumers who did not consume caffeine every day. This study was a double-blind, randomized placebo and active drug study. The 20 subjects were randomly assigned to receive caffeine (caffeine group; n = 10, mean age 26.8 +/- 5.2 years) or placebo (control group; n = 10, mean age 26.1 +/- 3.8 years). FBF was measured with the use of a mercury-filled Silastic strain-gauge plethysmograph (EC-5R, D.E. Hokanson, Inc., Bellevue, Washington). Three plethysmographic measurements were averaged to determine FBF at baseline and during the administration of each drug. FBF was calculated by 2 independent observers blinded to the study protocol from the linear portions of plethysmographic recordings. All measurements were performed for subjects in the supine position in a temperature-controlled (22°C to 25°C), quiet, dark laboratory. All subjects abstained from caffeine, ethanol, and nicotine for >/= 24 hours before the start of the study. After 30 minutes in the supine position, baseline FBF, heart rate, and arterial blood pressure were measured. Then the intra-arterial infusions of the endothelium-dependent vasodilator ACh (3.75, 7.5, and 15 ug/min) or the endothelium-independent vasodilator SNP (0.75, 1.5, and 3.0 ug/min) were performed randomly every 5 minutes, and FBF during the final 2 minutes of each infusion was measured. After a 30-minute rest period, caffeine 300 mg or placebo was administered orally to each subject. Baseline FBF, heart rate, and arterial blood pressure were measured 1 hour after the oral administration of caffeine or placebo. The effects of ACh and SNP were determined again by the same method as that used before caffeine and placebo administration. After a 30-minute rest period, NG -monomethyl-L –arginine (L -NMMA; Clinalfa Company, Läufelfiger, Switzerland), a nitric oxide synthase inhibitor, was infused intraarterially at a dose of 8 ug/min for 5 minutes while baseline FBF and arterial blood pressure were recorded, and Ach (3.75, 7.5, and 15 ug/min) was administered. The results are expressed as mean +/- SD. Values of p< 0.05 were considered to indicate statistical significance. Baseline characteristics between 2 groups were compared using the Mann-Whitney U-statistic test. The effects of interventions on blood pressure, heart rate, and FBF were analyzed with the paired Student’s t test. Comparisons of dose-response curves of parameters during the infusion of the drugs were analyzed with repeated-measures analysis of variance. The data were processed using the software package StatView V (SAS Institute Inc., Cary, North Carolina).
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How many outcome-specific endpoints are evaluated? 3
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Blood pressure (SBP and DBP)
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List additional health endpoints (separately). 2 Heart rate
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List additional health endpoints (separately).3 Endothelial function (forearm blood flow [FBF] response to acetylcholinesterase (ACh) or sodium nitroprusside (SNP)
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List additional health endpoints (separately).4
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List additional health endpoints (separately).5
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List additional health endpoints (separately).6
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Clinical, physiological, other Physiological
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What is the study design? Controlled Trial
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Randomized or Non-Randomized? RCT
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description FBF was measured with the use of a mercury-filled Silastic strain-gauge plethysmograph (EC-5R, D.E. Hokanson, Inc., Bellevue, Washington).
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Caffeine (general) Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other?
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Measured or self reported? Measured
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Children, adolescents, adults, or pregnant included? Adults
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Placebo controls
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) None
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What conflicts of interest were reported? No information provided
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Refid 17126666
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What were the sources of funding? No information provided
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Results & Comparisons

No Results found.