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Study Title and Description

Caffeine antagonism of alcohol-induced driving impairment.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on behavior*?
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Primary Publication Information
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TitleData
Title Caffeine antagonism of alcohol-induced driving impairment.
Author A Liguori,JH Robinson,
Country
Year 2001
Numbers

Secondary Publication Information
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Extraction Form: Behavior - Design Details - INCLUDED Studies
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Design Details
Question... Follow Up Answer Follow-up Answer
Refid 11376916
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What outcome is being evaluated in this paper? Behavior
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What is the objective of the study (as reported by the authors)? The extent to which caffeine antagonizes the effects of alcohol on automobile driving may depend in part on the amount of alcohol consumed. In a prior study of simulated driving, caffeine counteracted impairments at breath alcohol concentrations of 0.05–0.06%, but not 0.11% (Moskowitz and Burns, 1981). The authors concluded that caffeine cannot antagonize impairments from alcohol above the legal limit for driving, which then was 0.10%. The legal limit has since been reduced in sixteen states to 0.08%. Whether caffeine counteracts impairment of equilibrium and driving at this level of alcohol intake is less certain and was the focus of this study.
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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) Subjects Fifteen healthy nonsmoking adults (nine females, six males; 14 Caucasian, one African–American) with no self-reported history of either substance dependence or psychiatric disorder were recruited via newspaper advertisements. Persons who reported current use of (a) less than three or more than 14 alcohol drinks weekly, (b) less than 200 mg caffeine daily, or (c) any prescription or illicit psychoactive drugs were excluded from participation. The mean age of the subjects was 32 years (range 21–45) and their mean weight was 74 kg (range 53–115). The alcohol use disorders identification test (AUDIT; Saunders et al., 1993) was administered to each subject. All the subjects had scores of seven or less, indicating no current harmful or hazardous drinking. Most of this caffeine content came from coffee (ten subjects), soda (four subjects), or tea (one subject). Age, alcohol use, and caffeine use did not significantly differ between men and women. The mean (_x0001_SEM) body mass index of the male subjects (28_x0001_2) was significantly greater than that of the female subjects (23_x0001_1; t=2.4, P_x0002_<0.05). General study design All the subjects attended a practice session followed by six drug sessions. All the drug sessions were separated by at least 5 days. During the practice session, subjects learned the equipment, forms, and tasks. During each of the drug sessions, subjects swallowed a capsule (0, 200, or 400 mg caffeine) and a beverage (0.0 or 0.6 g/kg alcohol) in a 3×2 within-subjects design. Predrug procedures Subjects were instructed to abstain from food for 12 h and from caffeine and alcohol for 24 h before each session and from psychoactive drugs for the duration of the study. Abstinence from caffeine was verified by saliva sampling (EMIT® assay, Behring Diagnostics, San Jose, CA). Subjects then completed several baseline paper-and-pencil subjective effects questionnaires (see below). 2.2.3. Drug administration and testing At approximately 09:15 h, subjects received a capsule that they swallowed with 8 ounces of water. After 2 min, subjects received a beverage that they drank within 15 min. Forty-five minutes after finishing the beverage, subjects completed a 1-h test battery in a fixed order (dynamic posturography, critical flicker fusion, choice reaction time, Stroop Color Test, subjective effects scales, driving simulator). Physiological measures were collected during this 1-h period as described below. Subjects remained in the laboratory for 2 more h or until BrAC _x0002_0.05%, whichever came later. Subjectiv_x0001_e effects scales The Profile of Mood States (POMS; McNair et al., 1971) and ten 100-mm visual analog scales (VAS) were administered immediately before drinking began and 75 min after drinking ended. The visual analog scale items asked if subjects felt alert, confident, dizzy, drowsy, impatient, jittery, relaxed, tired, and if they liked the way they felt or had a headache. To control for predrug changes in mood across sessions, difference scores (postdrug minus predrug) from POMS subscales and VAS were analyzed. Two additional postdrug VAS asked whether subjects felt a drug effect or high. Drug preparation Each capsule contained caffeine (200 or 400 mg) or methylcellulose (placebo). Beverages with 0.6 g/kg alcohol included vodka (50% ethanol w/v) plus orange juice for a total volume of 16 ounces in a plastic cup. Placebo beverages contained only orange juice. To provide olfactory and taste cues of alcohol in all beverages, 5 ml of vodka (50% ethanol w/v) were spread around the top and sides of the cup via syringe. The order of dose presentation was randomized and doubleblind. Three subjects received placebo capsule and placebo beverage during the first session, two during the second, three during the third, two during the fourth, four during the fifth, and one during the sixth. 2.5. Data analysis POMS, VAS, CRT, CFF, Stroop, EquiTest, and brake latency scores were analyzed with one-way repeated measures ANOVAs with dose condition factor. Unless noted, all reported significant results are F(5, 70)_x0003_3.3, P_x0002_0.05. When significant results were found, Dunnett’s post hoc tests were used to compare the five drug conditions with placebo. When a drug condition significantly differed from placebo, Newman– Keuls pairwise comparisons were then used to compare (a) the two alcohol–caffeine combinations to alcohol alone and (b) the two caffeine doses to each other in the presence and absence of alcohol. To verify that there was no significant effect of practice or fatigue across sessions, one-way repeated measures ANOVAs with session order (first, second, etc. through sixth) factor were used to compare mean performance across sessions on the CRT, CFF, Stroop, EquiTest, and driving measures. Newman–Keuls pairwise comparisons were then used if ANOVA results were significant at P_x0002_0.05.
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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) Confusion
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List additional health endpoints (separately). Tired
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List additional health endpoints (separately)
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Notes VAS and POMS scales also looked at drug effects, alertness and confidence
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Clinical Clinical
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Physiological
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Other
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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? Subjective
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Optional: Name of Method or short description Subjecti_x0001_e effects scales The Profile of Mood States (POMS; McNair et al., 1971) and ten 100-mm visual analog scales (VAS) were administered immediately before drinking began and 75 min after drinking ended. The visual analog scale items asked if subjects felt alert, confident, dizzy, drowsy, impatient, jittery, relaxed, tired, and if they liked the way they felt or had a headache. To control for predrug changes in mood across sessions, difference scores (postdrug minus predrug) from POMS subscales and VAS were analyzed. Two additional postdrug VAS asked whether subjects felt a drug effect or high.
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Caffeine (general) Caffeine (general)
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Coffee
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Chocolate
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Energy drinks
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Gum
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Medicine/Supplement
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Soda
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Tea
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Measured Measured
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Self-report
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Children
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Adolescents
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Adults Adults
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Pregnant Women
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Control group (0 mg caffeine) vs (200 or 400 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) N/A
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Provide a general description of results (as reported by the authors). 3.2.1. POMS Caffeine alone did not significantly affect confusion–bewilderment ratings, and caffeine in the presence of alcohol did not significantly differ from alcohol alone. None of the drug conditions significantly differed from placebo on the other POMS scales. 3.2.2. VAS The 400 mg but not the 200 mg dose of caffeine alone significantly increased ratings of ‘jittery’. Post hoc analyses of significant results on ‘confident’ and ‘headache’ scales (F(5, 70)=2.5 and 2.6, respectively, P_x0002_0.05) revealed neither significant differences of alcohol or caffeine alone from placebo nor changes of the effects of alcohol by caffeine. There were also no drug effects on ratings of ‘do you like the way you feel now,’ ‘impatient’, ‘relaxed’, or ‘tired’.
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Did the authors perform a dose-response analysis (or trend/related analysis)? No
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What were the authors's observations re: trend analysis?
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What were the author's conclusions? Alcohol and caffeine separately produced significant changes in subjective measures, although not on the same items. Alcohol was associated with greater ratings of dizziness, confusion, drug effect, and high, while caffeine was associated with increases in jitteriness and alertness.
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What were the sources of funding? This study was supported by a gift from the R.J. Reynolds Tobacco Company.
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What conflicts of interest were reported? N/A
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Does the exposure (dose) need to be standardized to the SR? No
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Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest).
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List all the endpoint(s) followed by the dose (mg) which will be used in comparison to Nawrot.  Characterize value as LOAEL/NOAEL, etc. if possible.  Confusion - NOAEL = 400 mg Jittery - NOAEL = 200mg ; LOAEL = 400 mg Dizzy - NOAEL = 400 mg Headache - NOAEL = 400 mg Tired - NOAEL = 400 mg
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Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot. single dose some effects seen at levels equivalent to Nawrot.
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What is the importance of the study with respect to the adverseness of the outcome? Important
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