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Study Title and Description

Caffeine administration does not alter salivary α-amylase activity in young male daily caffeine consumers.



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 administration does not alter salivary α-amylase activity in young male daily caffeine consumers.
Author LC Klein,CA Whetzel,JM Bennett,FE Ritter,UM Nater,M Schoelles,
Country
Year 2014
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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)? Recent data suggest that caffeine alone may not alter sAA (salivary alpha-amlylase) activity [1]. We reported that basal caffeine levels in habitual caffeine users do not appear to be associated with basal sAA activity [1]. Further, daily caffeine intake does not appear to affect diurnal sAA patterns [13]. However, the direct effects of caffeine on sAA activity remain unknown. Therefore, we conducted a controlled laboratory experiment to examine the effects of caffeine administration on sAA activity in healthy young men who regularly consumed caffeine (i.e., at least 50 mg of caffeine per day).
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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) Respondents were excluded for significant health problems and the use of medications or drugs that could affect interpretation of neuroendocrine or cardiovascular data, could alter caffeine metabolism, or potentially could harm the participant if caffeine were administered, including history of: smoking or nicotine use, chronic medical conditions, medication use for any chronic physical and/or mental health conditions, and medications that could alter salivary biomarker data (e.g., oral or parenteral corticosteroids within prior 3 months, over-the-counter stimulants, flu/cold medications, caffeine- or ephedrine-containing supplements, cimetidine, quinolones, verapamil). Further, individuals with obesity (greater than 140% of ideal body weight) were excluded as determined by body mass index (BMI; weight/height2 ) > 30 [17] confirmed during the lab visit. A standard blood pressure cuff (Dinamap Compact Blood Pressure Monitor, Critikon, Tampa, FL) was placed on the non-dominant arm to collect systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR). Blood pressure values from this automated oscillometric blood pressure monitor are highly, positively correlated with intra-arterial and ambulatory blood pressure measurements [19,20]. After cuff placement, a sample blood pressure reading was taken to ensure that blood pressure levels fell within an acceptable range (i.e., SBP <140 mmHg, DBP <90 mmHg, HR <100 beats per minute). All participants met these criteria. Participants then were asked to complete three computerized tasks that measured working memory, reaction time, and visual attention (results not reported here), during which time blood pressure and HR were recorded every 2 minutes. Together, these 3 computerized tasks took 3– 5 minutes to complete. Following the computer tasks, participants were asked to swallow two gelatin capsules with a glass of water. Details about the capsules are reported in Klein et al. [1]. Each capsule contained either methylcellulose (placebo; Spectrum Chemicals, Gardena, CA) or a 200 mg Vivarin® (GlaxoSmithKline, Philadelphia, PA) pill. Using a randomized double-blind procedure, participants in the placebo group (N = 15) received two methylcellulose capsules, participants in the 200 mg caffeine group (N= 15) received 1 methylcellulose and 1 caffeine capsule, and participants in the 400 mg caffeine group (N= 15) received 2 caffeine capsules. This caffeine administration paradigm was selected based on previously published studies (e.g., [1,21,22]) and to parallel caffeine consumption outside the lab where individuals consume caffeine in the form of beverages (e.g., sodas, coffee) and food (e.g., chocolate). Based on our prior research [1], participants waited 20 minutes following capsule administration to allow for adequate caffeine absorption. This rest period ensured that participants completed the computerized task when plasma caffeine levels were on the ascending limb of the absorption curve [23,24]. Blood pressure and HR readings were taken every 2 minutes. This caffeine administration method and the timing of saliva collection results in a dose-dependent increase in caffeine and caffeine metabolite levels [1]. Systolic blood pressure, DBP, and HR readings were averaged across each experimental time period to derive mean baseline (5 readings), challenge (16 readings), and recovery (6 readings) measures for each participant [1].
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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) Heart rate
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List additional health endpoints (separately). 2 Blood pressure
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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? Subjective
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Optional: Name of Method or short description A standard blood pressure cuff (Dinamap Compact Blood Pressure Monitor, Critikon, Tampa, FL) was placed on the non-dominant arm to collect systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR).
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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 vs. 200 or 400 mg caffeine.
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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) Square root transformations were applied to the sAA data because they were not normally distributed [1,8]; this transformation resulted in a normal distribution of the data. Similarly, log-transformation of the cortisol data resulted in a normal distribution [1,28]. Thus, all sAA and cortisol statistical analyses are based on transformed values; raw sAA and cortisol values are reported unless otherwise noted. Separate repeated-measures analysis of variance (RMANOVA), with Caffeine Treatment (3 levels) as the independent measure and Time as the within-subject variable, were conducted to examine group differences in sAA and cortisol levels during the baseline and recovery phases of the experiment. A multivariate RM-ANOVA that included SBP, DBP, and HR as the dependent measures was used to examine group differences across baseline, task performance, and recovery. When appropriate, statistical interactions were examined using separate one-way ANOVAs, Tukey’ s honestly significant difference (HSD), and Bonferroni post-hoc analyses. All significance tests were two-tailed and evaluated at α = 0.05.
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What conflicts of interest were reported? "None of the authors have competing financial or personal interests to disclose."
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Refid 24410993
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What were the sources of funding? "This work was supported by the Office of Naval Research (ONR), Grant #N00014-03-1-0248 and the Penn State University General Clinical Research Center (NIH Grant M01 RR 10732). We appreciate the dedicated assistance of undergraduate students in the Biobehavioral Health Studies Lab and the GCRC nursing staff. Dr. Jeanette M. Bennett now is in the Department of Psychology at the University of North Carolina at Charlotte."
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