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Study Title and Description

Safety profile of caffeine and 1,3-dimethylamylamine supplementation in healthy men.



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 Safety profile of caffeine and 1,3-dimethylamylamine supplementation in healthy men.
Author RJ Bloomer,TM Farney,IC Harvey,RJ Alleman,
Country
Year 2013
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)? Within the weight loss and sport performance market, many individuals use caffeine and DMAA chronically at a much lower and recommended dosage (i.e. 150–250 mg caffeine and 25–50 mg DMAA). At such dosages and in conjunction with other ingredients contained within finished dietary supplements, we have noted no significant adverse outcomes in terms of elevations in resting heart rate, blood pressure, or blood borne markers of health (e.g. complete blood count, metabolic panel, lipid panel and liver function) in young, otherwise healthy subjects following eight and ten weeks of intake. In the present study, we extended our prior work by including (1) caffeine and DMAA alone and in combination (rather than as components of finished dietary supplements containing additional ingredients), (2) dosages of caffeine and DMAA that are routinely used by consumers of these ingredients, (3) an extended time frame of supplementation—12 weeks, and (4) additional measures of clinical safety—body mass and body composition, resting respiratory rate, 12-lead electrocardiography (ECG), urinalysis with microscopic examination, and oxidative stress, inflammatory, and cardiac biomarkers.
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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) (1) Subjects were prepped for a resting 12-lead ECG and rested quietly for 10 min. An ECG was then analyzed using automated procedures (Mac 1200; GE Medical System); (2) Blood pressure was measured using a stethoscope and cuff, while subjects were in a seated position.
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How many outcome-specific endpoints are evaluated? 5
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Blood pressure (SBP, DBP, rate pressure product)
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List additional health endpoints (separately). 2 Heart rate
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List additional health endpoints (separately).3 Heart rhythm (PR interval, P wave duration, QRS duration, WT interval, PP interval, RR interval)
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List additional health endpoints (separately).4 Cardiac biomarker data (C-reactive protein, troponin).
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List additional health endpoints (separately).5 Lipids (cholesterol, triglycerides, HDL-C, VLDL-C, LDL-C, Total/HDL-C).
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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 (1) Subjects were prepped for a resting 12-lead ECG and rested quietly for 10 min. An ECG was then analyzed using automated procedures (Mac 1200; GE Medical System); (2) Blood pressure was measured using a stethoscope and cuff, while subjects were in a seated position. Venous blood samples (*20 mL) were taken from subjects via needle and Vacutainer1. Blood samples were collected before starting supplementation (Pre) and after 6 and 12 weeks of supplementation. Following collection, samples were processed accordingly and fresh samples were analyzed for complete blood count (Coulter LH750, Beckman Coulter, Inc.), comprehensive metabolic panel (Roche/Hitachi Modular), and lipid panel (Roche/Hitachi Modular).
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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. 250 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) Subjects were not current smokers and were considered to be in good overall health. They did not have a history of cardiovascular, neurological, or metabolic disorders (e.g. hypertension, seizures, and diabetes). Subjects were regular consumers of stimulants (e.g. caffeine) such as beverages or nutritional supplements, who did not report a history of adverse reactions to caffeine or other stimulants. Data were analyzed using a 4 (condition) by 3 (time) analysis of variance. Tukey’s post hoc testing was used as needed. The data are presented as mean+SEM. All analyses were performed using JMP statistical software. Statistical significance was set at p </= 0.05.
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What conflicts of interest were reported? RJB has been a Consultant for and/or Principal Investigator on research studies funded by various dietary supplement companies.
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Refid 23424215
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What were the sources of funding? Funding for this work was provided in part by USPlabs, LLC, and the University of Memphis.
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