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Study Title and Description

Coffee blunts mental stress-induced blood pressure increase in habitual but not in nonhabitual coffee drinkers.



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 Coffee blunts mental stress-induced blood pressure increase in habitual but not in nonhabitual coffee drinkers.
Author I Sudano,L Spieker,C Binggeli,F Ruschitzka,TF Lüscher,G Noll,R Corti,
Country
Year 2005
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)? It was the aim of the present study to assess the effects of coffee on the cardiovascular response to mental stress (MS) and cold pressor test (CPT) in humans.
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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) Study Population MSA was investigated by microneurography within the peroneal nerve in 15 healthy volunteers (6 habitual and 9 nonhabitual coffee drinkers; 10 male and 5 female) as described previously. [NOTE: Corti et al., 2002]. Smokers and offspring of hypertensive parents were excluded. Experimental Protocol Arterial BP, HR, and MSA were recorded continuously during 10-minute baseline, 3-minute MS, and 2-minute CPT before and after ingestion of a triple espresso. [NOTE: Two additional groups received intravenous caffeine or placebo, which are not relevant.] Subjects experienced the interventions on different days, and the order of interventions was randomized. Habitual coffee drinkers and nonhabitual coffee drinkers (defined as drinking no coffee or any other beverages containing caffeine) were studied after coffee drinking (triple espresso; n=10; 5 habitual and 5 nonhabitual coffee drinkers). All subjects were studied in supine position after coffee abstinence for >/- 16 hours under standardized conditions (ie, in the afternoon [2:00 PM]) after a light meal and after micturition) to avoid any increase in sympathetic activity through bladder distension. Caffeine levels were determined at baseline and after 30, 60, and 90 minutes after oral ingestion of coffee. Coffee Preparation Coffee was prepared with an espresso machine (triple espresso; 30 mL). Microneurography Multifiber recordings of MSA were obtained from the peroneal nerve posterior to the fibular head with tungsten microelectrodes (200-um shaft diameter, 1- to 5-um uninsulated tip; Medical Instruments; University of Iowa). A reference electrode was inserted subcutaneously 1 to 2 cm from the recording electrode. Electrodes were connected to a preamplifier (gain 1.000) and amplifier (variable gain 10 to 50). Neural activity was fed through a band-pass filter (bandwidth 700 to 2000 Hz) and a resistance-capacitance integrating network (time constant 0.1 seconds) to obtain a mean voltage neurogram with the typical pulse wave–triggered bursts. ECG and BP An ECG was recorded simultaneously throughout the experiment. BP was assessed noninvasively through oscillometric occlusion at the left upper arm (Dinamap; Critikon Inc) every 2 minutes, and it was also measured continuously with a Finapress device15 (Finapress 2300; Ohmeda) during 10-minute baseline, 3-minute MS, and 2-minute CPT. The analysis of BP, HR, and MSA was done by an investigator blinded to the experiment and to the subject’s data. Signal Recording and Signal Processing MSA and 1-lead surface ECG were recorded continuously with a LabView application, an MIO 16L (National Instruments) analog-to-digital conversion board, and a Macintosh computer. The signals were sampled at 500 Hz and stored with 12-bit accuracy. MSA was quantified in a computer-assisted evaluation of the frequency and the amplitude of the sympathetic bursts. The results are expressed as cumulative sum of the amplitude in volts per minute (V/min) and percent increase in respect to baseline. As already described for BP and HR, MSA was also analyzed by an investigator not aware of the interventions. Data and Statistical Analysis Data were entered and analyzed with SYSTAT version 10.0 (SPSS, Inc). For each subject, a 5-minute average of continuously acquired data at baseline or 90 minutes after oral coffee was used. For analyzing MS and CPT, continuously acquired data were averaged for every minute of the tests. Results are reported as mean +/- SD. Data were analyzed with repeated-measures ANOVA. The effect of interventions was evaluated by comparing the values before and after MS and CPT with a t test. A value of P<0.05 was considered statistically significant.
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How many outcome-specific endpoints are evaluated? 3
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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 Muscle sympathetic activity (MSA)
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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 BP was assessed noninvasively through oscillometric occlusion at the left upper arm (Dinamap; Critikon Inc) , and it was also measured continuously with a Finapress device15 (Finapress 2300; Ohmeda). MSA and 1-lead surface ECG were recorded continuously with a LabView application, an MIO 16L (National Instruments) analog-to-digital conversion board, and a Macintosh computer.
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Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other? Coffee
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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 (baseline)
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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 provided
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Refid 16103273
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What were the sources of funding? This study was partially funded by the Swiss National Research Foundation (NF-3200B0-100318/1 and NF-32-065447.01).
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Results & Comparisons

No Results found.