Advanced Search

Study Preview



Study Title and Description

Caffeine and stress alter salivary alpha-amylase activity in young 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?
  • Comments Comments (
    0
    ) |

Primary Publication Information
  • Comments Comments (
    0
    ) |
TitleData
Title Caffeine and stress alter salivary alpha-amylase activity in young men.
Author LC Klein,JM Bennett,CA Whetzel,DA Granger,FE Ritter,
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
  • Comments Comments (
    0
    ) |
What is the objective of the study (as reported by the authors)? We examined the effects of caffeine and a psychological stressor on salivary a-amylase (sAA) in healthy young males (age 18– 30 years) who consumed caffeine on a daily basis.
  • Comments Comments (
    0
    ) |
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) Participants: Forty-five healthy men, 18–30 years of age (mean age 21.16+/-0.35 years), were recruited to participate in a study examining caffeine and task performance. To minimize the impact of caffeine metabolism and absorption on findings, men only were included in this initial study because of known sex differences in caffeine pharmacokinetics. Potential participants were recruited through flyers posted in the local community and on the Penn State campus. Eligibility was determined by a trained research assistant who reviewed the health history of potential participants in a telephone interview. All eligible participants were daily caffeine users who consumed at least 50 mg of caffeine per day. In addition to daily caffeine use, respondents were asked questions to document significant health problems and the use of medications or drugs that could affect interpretation of neuroendocrine or cardiovascular data, could alter caffeine metabolism, or could harm the participant if caffeine were administered, including: a history of smoking or nicotine use, angina, arrhythmia, medications for blood pressure, diagnosed insulin-dependent diabetes, betablocker medication use, inhaled beta agonist use, learning disability, attentional disorder, recent head trauma, history of depression or other psychiatric illness (e.g., anxiety), stroke, seizures, or other focal brain lesion, or a history of other neurological disorders. Likewise, anyone taking the following medications was excluded from participating: oral or parenteral (injected) corticosteroids within 3 months, psychostimulants, over-the-counter stimulants, cold or flu medications, ephedrine or caffeine-containing supplements, cimetidine, quinolones, verapamil, or benzodiazepines. Further, potential participants using psychotropic medications within the previous 8 weeks or with psychiatric hospitalization within the past year were excluded, as were individuals with severe obesity (greater than 140% of ideal body weight). Individuals also were screened and excluded for symptoms of depression using the Center for Epidemiological Studies Depression Scale (CES-D; Radloff, 1977). Experimental protocol: Baseline - Following completion of the questionnaires, a standard blood pressure cuff (Dinamap Compact Blood Pressure Monitor, Critikon, Tampa, FL) was placed on the nondominant arm to collect systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR. This automated oscillometric monitor has been shown to yield blood pressure values that are highly correlated with intra-arterial and ambulatory blood pressure measurements (Borow and Newburger, 1982; Mueller et al., 1997). 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). Participants whose cardiovascular readings did not meet these criteria were excluded from the study (N.3); their data are not reported here. Participants were asked to sit quietly for 10 min while five baseline blood pressure readings were taken automatically at 2-min intervals. Participants were asked to complete a computerized working memory task, reaction time, and signal detection task (results not reported here), during which time blood pressure and HR were recorded every 2 min. These tasks took no more than 15 min to complete. Caffeine administration - Following the computer tasks, participants were asked to swallow two gelatin capsules with a glass of water. The capsules were green in color, made of vegetable oil, and easily digestible (Size 1 KCaps Vegetarian Capsules, Capsuline1, Pompano Beach, FL). Each capsule contained either methylcellulose (placebo; Spectrum Chemicals, Gardena, CA) or a 200mg Vivarin1 (GlaxoSmithKline, Philadelphia, PA) pill. Using a randomized double-blind procedure, participants in the placebo group (N.15) received two methylcellulose capsules, participants in the 200mg caffeine group (N.15) received one methylcellulose and one caffeine capsule, and participants in the 400mg caffeine group (N.15) received two caffeine capsules. This caffeine administration paradigm was selected based on previously published studies (e.g., Lane et al., 2002; Lieberman et al., 2002) and to more closely parallel caffeine consumption outside the laboratory where individuals consume caffeine in the form of beverages (e.g., sodas, coffee) and food (e.g., chocolate). After capsule administration, participants were asked to rest for 20min to allow for adequate caffeine absorption and to ensure that participants were completing the mental arithmetic task when plasma caffeine levels were on the ascending limb of the absorption curve (Bonati et al., 1982; Liguori et al., 1997); blood pressure and HR readings were taken every 2 min. Math challenge: Next, a trained investigator (LCK) entered the room to administer the stressor which was a serial subtraction task drawn from the Trier Social Stress Task (Kirschbaum et al., 1993). Specifically, participants were asked to count backwards by 70 and 130s two different times; each counting segment lasted for 4 min. Task performance was voice recorded on a digital camera and laptop computer for later assessment of accuracy and speed (for task performance results see Bennett et al., 2006). This challenge session took 25 min to complete; blood pressure and HR were recorded every minute during this time period. Recovery: Following completion of the math challenge, participants again were asked to complete the computer cognitive tasks and then the second saliva sample was collected. Next, participants were asked to rest for a 15-min recovery period. Blood pressure and HR were recorded every 2 min throughout the computer and recovery periods. Blood pressure and heart rate: Blood pressure and heart rate. Aggregation across two measures of basal resting SBP and DBP in a laboratory setting has been shown to provide within subject reliability of +0.90 or better (Llabre et al., 1988). Therefore, SBP and DBP readings, along with HR, were averaged across each experimental time period to derive mean baseline (5 readings), challenge (16 readings), and recovery (6 readings) measures for each participant.
  • Comments Comments (
    0
    ) |
How many outcome-specific endpoints are evaluated? 2
  • Comments Comments (
    0
    ) |
What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Blood pressure
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately). 2 Heart rate
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).3
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).4
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).5
  • Comments Comments (
    0
    ) |
List additional health endpoints (separately).6
  • Comments Comments (
    0
    ) |
Clinical, physiological, other Physiological
  • Comments Comments (
    0
    ) |
What is the study design? Controlled Trial
  • Comments Comments (
    0
    ) |
Randomized or Non-Randomized? RCT
  • Comments Comments (
    0
    ) |
What were the diagnostics or methods used to measure the outcome? Objective
  • Comments Comments (
    0
    ) |
Optional: Name of Method or short description A standard blood pressure cuff (Dinamap Compact Blood Pressure Monitor, Critikon, Tampa, FL) was placed on the nondominant arm to collect systolic blood pressure (SBP), diastolic blood pressure (DBP), and HR.
  • Comments Comments (
    0
    ) |
Caffeine (general) Caffeine (general)
  • Comments Comments (
    0
    ) |
Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other?
  • Comments Comments (
    0
    ) |
Measured or self reported? Measured
  • Comments Comments (
    0
    ) |
Children, adolescents, adults, or pregnant included? Adults
  • Comments Comments (
    0
    ) |
What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Placebo
  • Comments Comments (
    0
    ) |
What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) anyone taking the following medications was excluded from participating: oral or parenteral (injected) corticosteroids within 3 months, psychostimulants, over-the-counter stimulants, cold or flu medications, ephedrine or caffeine-containing supplements, cimetidine, quinolones, verapamil, or benzodiazepines. Further, potential participants using psychotropic medications within the previous 8 weeks or with psychiatric hospitalization within the past year were excluded, as were individuals with severe obesity (greater than 140% of ideal body weight). Separate repeated-measures analysis of variance (ANOVA), with Caffeine Treatment (three levels) as the independent measure and Time as the within subject variable, were conducted to examine group differences in SBP, DBP, HR, sAA, and caffeine levels during the baseline, challenge (SBP, DBP, HR only), and recovery phases of the experiment.
  • Comments Comments (
    0
    ) |
What conflicts of interest were reported? Were not discussed.
  • Comments Comments (
    0
    ) |
Refid 20589924
  • Comments Comments (
    0
    ) |
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).
  • Comments Comments (
    0
    ) |




Results & Comparisons

No Results found.