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Study Title and Description

Cardiovascular responses to caffeine by gender and pubertal stage.



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 Cardiovascular responses to caffeine by gender and pubertal stage.
Author JL Temple,AM Ziegler,A Graczyk,A Bendlin,T Sion,K Vattana,
Country
Year 2014
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)? Caffeine use is on the rise among children and adolescents. Previous studies from our laboratory reported gender differences in the effects of caffeine in adolescents. The purpose of this study was to test the hypotheses that gender differences in cardiovascular responses to caffeine emerge after puberty and that cardiovascular responses to caffeine differ across the phases of the menstrual cycle.
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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) Experimental procedures: Participants visited the laboratory on 6 occasions: 3 visits during 1 week with the remaining 3 visits occurring 2 weeks later. For the 15- to 17-year-old girls, 3 of the sessions occurred during the midfollicular phase of the menstrual cycle and 3 occurred during the midluteal phase. Prepubertal participants and postpubertal boys received each caffeine dose on 2 separate visits in order to equalize the number of visits. Participants were randomly assigned to order of caffeine administration by using a random number table. Participants were asked to abstain from all soda and caffeine-containing products for 24 hours before their appointment times, as well as from all food and drink other than water for 2 hours before their appointments. At each visit, participants provided saliva samples, completed 24-hour food and physical activity recalls, and completed the Behavioral Checklist at baseline and after 60 minutes. Participants then consumed a 300-mL portion of lemon-lime–flavored soda, orange juice, or lemonade containing either placebo or caffeine (1.0 or 2.0 mg/kg; order counterbalanced) and had cardiovascular measurements taken. The participants and parents were not told directly that caffeine was being manipulated, although it was listed as a possibility. Caffeine preparation: Caffeine solutions were created by adding caffeine to a flattened, lemon-lime– flavored soda at 2 doses, 1 mg/kg (10 mg/ mL caffeine/soda) and 2 mg/kg (20 mg/ mL caffeine/soda), and then freezing aliquots.
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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 (systolic and diastolic).
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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 An automated heart rate and blood pressure monitor (NIBP 2400; Welch Allyn, Skaneateles, NY) was used to measure cardiovascular variables.
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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? Children, Adolescents
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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. 1 or 2 mg/kg 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) Eligible participants were nonsmokers, had previous experience with caffeine and had no adverse reactions, were not using hormone-based contraceptives and/or were not pregnant, were not taking any medications affecting caffeine metabolism, and were willing to abstain from regular caffeine use. Gender and pubertal group differences in participant characteristics were analyzed by using either an analysis of variance (BMI, age, caffeine consumption, and Tanner stage) or x2 analyses for categorical variables (race, household income, and parental education). After confirming that the data did not differ as a function of visit for prepubertal boys and girls and postpubertal boys, the data from the same-dose sessions were averaged. The pattern of diastolic and systolic blood pressure and heart rate were analyzed by using mixed-effects regression models with gender and pubertal group as the time-invariant predictors time (from 10 to 60 minutes after caffeine administration) and caffeine dose (0, 1, or 2 mg/kg) as time-variant predictors, and average daily caffeine use (mg/day) and baseline blood pressure and heart rate as covariates. We used unstructured models with the intercept, identifier (ID), and time treated as random variables. The Akaike information criteria (AIC) for these models were as follows: 25 373 (heart rate), 25 026 (systolic blood pressure), and 22 108 (diastolic blood pressure). Answers on the behavioral checklist were analyzed by using a mixed repeated-measures analysis of covariance with gender and pubertal group as between-subject variables, caffeine dose (0, 1, or 2 mg/kg) and pre/post as within-subject variables, and average daily caffeine use (mg/ day) as a covariate. To confirm menstrual cycle phase, we analyzed salivary steroid hormone concentrations during the self-reported follicular and luteal phases in postpubertal girls only. For analysis of differences across the menstrual cycle, postpubertal girls were selected and a mixed-effects regression model was applied with caffeine dose (0, 1, or 2 mg/kg) and menstrual cycle phase (luteal versus follicular) as time-variant predictors and baseline blood pressure and heart rate and average daily caffeine use (mg/day) as covariates. The regression analyses were conducted by using SAS 9.3 (SAS Institute, Cary, NC), and the other analyses were conducted by using SYSTAT 11.0 (Systat Software, San Jose, CA).
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What conflicts of interest were reported? "The authors have indicated they have no financial relationships relevant to this article to disclose."
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Refid 24935999
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What were the sources of funding? "This study was funded by a grant from the National Institute on Drug Abuse (RO1 DA030386) to Dr Temple. Funded by the National Institutes of Health (NIH)."
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Results & Comparisons

No Results found.