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Study Title and Description

The effects of dietary caffeine use and abstention on blood oxygen level-dependent activation and cerebral blood flow



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 The effects of dietary caffeine use and abstention on blood oxygen level-dependent activation and cerebral blood flow
Author M. A. Addicott, A. M. Peiffer and P. J. Laurienti
Country
Year 2012
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)? The objective of this study was to evaluate the effect of recent use or abstinence from dietary caffeine on blood oxygen level-dependent (BOLD) signal associated with functional magnetic resonance imaging (fMRI).
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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) Subjects Healthy adults (ages 18–50 years) were recruited from the Winston-Salem, North Carolina area with flyers, newspaper advertisements, and by word of mouth. Potential volunteers were assessed with a physical medical screening before inclusion in the study. Participants were identified as low ( < 200mg/day), moderate (200–600mg/day), and high ( > 600mg/day) caffeine users based on a 7-day caffeine consumption diary21 completed the week after the screening session. This diary is a modified version of the Caffeine Consumption Questionnaire,22 and estimates are based on caffeine content information of common beverages (Center for Science in the Public Interest www.cspinet.org). Forty-five participants were included (20 men) in Study 1. There were 18 low consumers (mean– SD: 45– 38 mg/day), 9 moderate consumers (405– 103mg/day), and 18 high consumers (950– 237mg/day); the average age was 32– 9 years. Seventeen moderate (200–600mg/day) consumers were included (eight men) in Study 2; the average age was 30–8 years. The average caffeine intake was 375– 101mg/day. The results for Study 2 were reported in this paper. Procedure Each subject underwent a fMRI on four occasions, separated by at least 1 week. On two occasions, the subjects were instructed to maintain normal caffeine use until 90 minutes before the scan (satiated state); on the other two occasions, the subjects were instructed to abstain from caffeine for 30 hours before the scan (abstained state). In each state, participants were administered caffeine (250mg anhydrous) on 1 day and a matching placebo capsule on the other day in a double-blind manner. The four State by Drug conditions are abbreviated as follows: abstained placebo (AP), abstained caffeine (AC), satiated placebo (SP), and satiated caffeine (SC). State and Drug conditions were counter-balanced and pseudo-randomized to eliminate time as a variable. To verify compliance, saliva samples were obtained on arrival to the study visit and 45 minutes after capsule ingestion. Image acquisition For resting-state cerebral blood flow (CBF) measurements, participants were instructed to keep their eyes open and gaze at a fixation cross. One hundred and twenty images were collected (60 pairs) for analysis during a 6 minutes 30 second scan. Perfusion scans were cleaned of paired images that were poorly aligned (e.g., > 2.5 standard deviations from the mean) due to motion artifact. Data analysis In Study 2, the average whole-brain gray matter CBF values were analyzed using a 2 (State) x 2 (Drug) repeated-measures ANOVA. Due to artifacts, CBF data were excluded from two conditions between two subjects. Missing data were replaced with the group mean for the ANOVA. Time course and CBF data were analyzed using SPSS 16.0; results were considered significant if p <0.05.
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How many outcome-specific endpoints are evaluated? 1
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) cerebral blood flow
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List additional health endpoints (separately). 2
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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? NCT
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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
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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.) Each subject served as his/her own control
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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? The authors Addicott, Peiffer, and Laurienti have no conflicts of interest to disclose.
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Refid 10018
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What were the sources of funding? These studies were supported by grants from the National Institutes of Health (EB03880, EB004673, DA024950, and RR07122).
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Results & Comparisons

No Results found.