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Study Title and Description

Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users.



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 Subjective, behavioral, and physiological effects of acute caffeine in light, nondependent caffeine users.
Author E Childs,H de Wit,
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)? The present study was designed to investigate the effects of acute caffeine administration in individuals who do not regularly consume caffeine.
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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 Male (N=51) and female (N=51) participants aged 18–35 were recruited from the University and surrounding community via posters, newspaper advertisements, and word-of-mouth referrals. All subjects were light, nondependent caffeine users reporting consumption of less than 300 mg per week from caffeinated beverages and dietary sources. To quantify habitual use of caffeine, subjects were queried in detail by an interviewer about all dietary sources of caffeine, including tea and coffee, soft drinks, chocolate, and over the counter medications. Subjects also kept a detailed diary of beverage and chocolate consumption for 2 weeks before testing. Exclusion criteria included a current or prior diagnosis of Major Axis I DSM-IV disorder including drug abuse or dependence, high levels of anxiety or depression, any history of psychosis, less than a high school education, lack of fluency in English, a body mass index outside of 19–26 kg/m2, night shift work, use of the birth control pill in females, pregnant or lactating women, or women planning to become pregnant during the study, high blood pressure, abnormal electrocardiogram, or daily use of any medications. Daily cigarette use was also an exclusion criterion. For blinding purposes, volunteers were advised that they might receive one of several classes of drugs. Design The study utilized a four-session, double blind, placebo-controlled, within-subject design. Placebo, or 50, 150, or 450 mg caffeine were administered separately in random order during the four test sessions, conducted at least 72 h apart. Sessions were conducted between 9 a.m. and 1 p.m. Procedure Participants were tested individually in comfortably furnished rooms with a television/VCR, magazines, and a computer for administering questionnaires and tasks. Subjects were allowed to watch television, movies, or read when no measures were being obtained, but they were not allowed to work or study. Subjects refrained from eating from midnight on the night previous to sessions and were given a light snack (bagel) upon arrival in the laboratory. Thirty minutes later, they consumed capsules containing 0, 50, 150, or 450 mg caffeine. Heart rate and blood pressure were obtained 20 min before and at 30, 60, and 90 min after capsule administration using a digital blood pressure monitor (Dinamap 1846SX, Critikon, Tampa, FL). Data Analysis For subjective and physiological measures, data were expressed as peak change from baseline (20 min pre-capsule) for each session and were analyzed by one within-subject factor (dose) repeated measures analysis of variance (ANOVA). A significant main effect was further analyzed by performing post hoc pairwise comparisons with Bonferroni correction. Differences were considered to be significant if P<0.05. All analyses were performed using SPSS version 12.0 for Windows.
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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 Heart rate and blood pressure were obtained using a digital blood pressure monitor (Dinamap 1846SX, Critikon, Tampa, FL).
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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 was reported
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Refid 16541243
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What were the sources of funding? This research was supported by NIDA (DA02812) and the General Clinical Research Center (USPHS MO1RR00055).
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Results & Comparisons

No Results found.