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Study Title and Description

Caffeine effects on resting-state arousal.



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 Caffeine effects on resting-state arousal.
Author RJ Barry,JA Rushby,MJ Wallace,AR Clarke,SJ Johnstone,I Zlojutro,
Country
Year 2005
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 examined the use of caffeine to manipulate arousal level without the confounds associated with task-related activation.
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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) Participants Participants were 18 university undergraduates (13 females) recruited from the undergraduate psychology pool at the University of Wollongong. Their mean age was 21 years (range 17–36), and 17 subjects were right handed. Subjects were screened for neurological disease, head injury, learning disability and psychiatric conditions. Participation was restricted to non-smokers. Participants were moderate caffeine consumers (i.e. they regularly consumed 2–4 cups of coffee or cola equivalents daily) and were required to abstain from caffeine and other psychoactive substances for at least 12 h prior to each testing session. Autonomic Measures HR was recorded via an electrocardiogram using a pair of pre-jelled disposable Ag/AgCl electrodes, with electrodes at mid-sternum and over the third rib on the left mid-axillary line. BP was recorded continuously using a Finapres Ohmeda 2300, with a finger cuff over the medial phalange of digit IV on the non-dominant hand. Procedure When participants arrived in the laboratory they were fitted with the physiological measurement equipment, seated in an air-conditioned sound attenuated recording booth and administered one of two identical gelatine capsules, containing either 250 mg caffeine or placebo, in a pre-determined randomised order. Both subjects and experimenters were blind to the contents of the capsule. The capsule was administered with the participant’s choice of apple juice, milk and biscuits. They then began a testing session of approximately 1 h consisting of (a) 2 min eyes closed followed by 2 min eyes open, with each change signalled by a brief (20 ms duration with 15 ms rise- and fall-times) 1000 Hz 80 dB tone, for a total of 32 min; (b) an active auditory oddball task lasting approximately 12 min; (c) alternating 2 min eyes open followed by 2 min eyes closed, as in part (a), for a total of 16 min. Subjects returned for a second test at the same time 1 week later, when the same procedure was followed and the alternate capsule was administered. Data Extraction The last 2 min of the eyes-closed resting condition in part (a) was chosen for analysis. This epoch began approximately 30 min (mean 32.0 min, range 29–35 min) after capsule ingestion, Statistical Analysis Autonomic measures were examined in separate repeated-measures ANOVAs testing for differences due to condition (caffeine vs. placebo).
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How many outcome-specific endpoints are evaluated? 2
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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
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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 HR was recorded via an electrocardiogram. BP was recorded continuously using a Finapres Ohmeda 2300.
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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.) Subjects served as their own 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 16221568
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What were the sources of funding? No information provided
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Results & Comparisons

No Results found.