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Study Title and Description

Caffeine and blood pressure response: sex, age, and hormonal status.



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 and blood pressure response: sex, age, and hormonal status.
Author NH Farag,TL Whitsett,BS McKey,MF Wilson,AS Vincent,SA Everson-Rose,WR Lovallo,
Country
Year 2010
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)? We compared the effect of caffeine on BP in age-matched men and pre- and postmenopausal women, including those taking and not taking hormone replacements (HR). We hypothesized that men and postmenopausal women not taking HR would show the largest BP response to 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) Materials and methods: A total of 165 healthy men and women ages 35 to 64 yrs were recruited from the general populations of Buffalo, NY and Oklahoma City, OK. Subjects were stratified into 6 groups; men and premenopausal women (35–49 yrs) vs men and postmenopausal women (50–64 yrs), with postmenopausal women divided into those taking no hormone replacements (NHRT), estrogen alone (ERT), or estrogen and progesterone (HRT) (Table 1). All were nonsmokers, nonobese (BMI <30), and in good health by self-report and routine physical examination. Subjects were excluded if they had a history or displayed current evidence of heart disease, liver or renal disease, diabetes, severe asthma, or cerebrovascular disease. They had BP in the normotensive range (BP <135/85) at screening, regularly consumed 50 to 700mg/day of caffeine by structured report, and used no prescription medications other than HRT in postmenopausal women. Study design caffeine dosing, and compliance: In a randomized, 2-week crossover design, subjects consumed a placebo (3 inactive capsules) during home maintenance for 6 days and also consumed a placebo (1 inactive capsule) on day 7 in the lab. The other week involved ingestion of caffeine during home maintenance for 6 days (80 mg, 3x=day) and a 7th day of caffeine lab challenge (250 mg). The crossover conditions were counterbalanced. Home maintenance doses were supplied in bottles of identical gelatin capsules (College of Pharmacy, University of Oklahoma, Oklahoma City) containing either lactose or lactose mixed with 80mg of U.S. Pharmacopeia (USP) caffeine (Professional Compounding Centers of America, Houston, TX). Subjects were instructed to eliminate all caffeine from their diet during the 2 weeks of the study. During home maintenance, subjects were instructed to take one capsule at 8:00 am, 1:00 pm, and 6:00 pm each day. Subjects were instructed to eliminate all caffeine from their diet during the 2 weeks of the study. Test day challenge doses were supplied in capsules containing either lactose or lactose mixed with 250mg of USP caffeine (Gallipot, St. Paul, MN). Lab protocol: The lab protocol included the following activities: breakfast that was designed to be consistent in nutritional value and quantity across test days, instrumentation for BP and heart rate (HR) measurement, a rest period (20 min), and predrug BP baseline (10 min), capsule, and postdrug response (60 min). BP was measured every 3 minutes during screenings and test sessions using a Dinamap 845 oscillometric vital signs monitor (Critikon, Tallahassee, FL). Compliance with home dosing was assessed by capsule counts, by caffeine assay of saliva specimens collected at home each day at 7:00 pm (Salivette, Starstedt, Germany), and from a saliva specimen collected each morning upon entering the lab. Salivary caffeine concentrations are equivalent to those found in serum across a wide range of caffeine doses. Subjects found to be noncompliant by any of these criteria were dropped and replaced (n=5).
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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? Objective
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Optional: Name of Method or short description Compliance with home dosing was assessed by capsule counts, by caffeine assay of saliva specimens collected at home each day at 7:00 pm (Salivette, Starstedt, Germany), and from a saliva specimen collected each morning upon entering the lab. Salivary caffeine concentrations are equivalent to those found in serum across a wide range of caffeine doses. Subjects found to be noncompliant by any of these criteria were dropped and replaced (n=5).
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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 treatment. Cross-over design.
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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 excluded if they had a history or displayed current evidence of heart disease, liver or renal disease, diabetes, severe asthma, or cerebrovascular disease. Baseline differences among groups were tested using the univariate analysis of variance (ANOVA), with posthoc comparisons using Holm’s sequentially selective Bonferroni method. Age was adjusted for by using it as a covariate in the ANOVA models. Group differences in response to caffeine vs placebo were tested using ANOVA on each dependent variable in a 2 Drug_2 Week_ 6 Group design. Models were adjusted for age by using it as a covariate in the analyses. Significant main effects or interactions were followed by pairwise comparisons of response to caffeine vs response to placebo. Differences were deemed statistically significant if p<0.05.
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What conflicts of interest were reported? Authors noted no competing financial interests.
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Refid 20500126
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What were the sources of funding? This work was supported by NHLBI grant no. HL32050 and NIRR grant no. M01-RR14467 from the National Institutes of Health, Bethesda, Maryland.
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Results & Comparisons

No Results found.