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Study Title and Description

Challenging sleep in aging: the effects of 200 mg of caffeine during the evening in young and middle-aged moderate caffeine consumers.



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 Challenging sleep in aging: the effects of 200 mg of caffeine during the evening in young and middle-aged moderate caffeine consumers.
Author C Drapeau,I Hamel-Hébert,R Robillard,B Selmaoui,D Filipini,J Carrier,
Country
Year 2006
Numbers

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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 16704567
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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 aim of this study was to evaluate the effects of a 200-mg administration of caffeine on polysomnographic sleep variables and quantitative sleep electroencephalography (EEG) in 12 young (20–30 years) and 12 middle-aged (40–60 years) moderate caffeine consumers (one to three cups of coffee per day).
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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 Twenty-four healthy subjects were separated into two groups according to age: young (six men and six women; 20–30 years; mean age: 23.8, SEM: 0.66) and middle-aged (five men and seven women; 40–60 years; mean age: 50.3, SEM: 1.62). All subjects were in good health according to their medical history. They were all non-smokers and free of any drug or medication that affect the sleep–wake cycle. During the screening, subjects reported to be moderate caffeine consumers (equivalent to one to three cups of coffee per day; mean consumption: equivalent to 1.8 cups, SEM: 0.17). Finally, none of the subjects reported any sleep problems. Subjects were instructed to abstain from alcohol and medication during the laboratory component of the experiment. While the study included both pre- and postmenopausal women, peri-menopausal women as well as women using hormonal contraceptives or receiving hormonal replacement therapy were excluded. Procedure Subjects came to the chronobiology laboratory for three nonconsecutive nights, each of which was separated by 6–9 days. The first night was considered to be both an adaptation and screening night, whereas the other two nights were considered to be experimental nights. Starting 1 week prior to the first night and until the end of the study, subjects were instructed to keep a regular sleep–wake pattern within 30 min of their habitual sleep–wake schedule, and to maintain their habitual caffeine intake. During this time, they were asked to complete the French version of the _x0002_Pittsburgh Sleep Diary_x0001_ on a daily basis (Monk et al., 1994). Bedtime and waketime in the laboratory were based on the subject’s habitual sleep–wake cycle, averaged from their sleep diary. On a daily basis, subjects reported the amount of caffeine products they had consumed (i.e. coffee, tea, chocolate, etc.). The mean number of milligrams of caffeine consumed per day was approximated for each subject according to the following criteria: 250 mL of coffee = 100 mg of caffeine; 250 mL of tea = 50 mg of caffeine; 250 mL of cola = 35 mg of caffeine; 10 g of chocolate = 5 mg of caffeine. On experimental days, subjects were required to abstain from alcohol, and were permitted to maintain their habitual caffeine consumption in the morning, so as to prevent potential effects of caffeine withdrawal. Starting at noon, subjects stopped consuming caffeine-containing beverages and foods. Subjects were submitted to both a caffeine (200 mg; equivalent of 1–2 cups of coffee) and a placebo (lactose) condition, in a double-blind cross-over design. This dose of caffeine is considered to be moderate, and produces significant effects on the sleep of young subjects (Landolt et al., 1995a). Subjects received one capsule containing either caffeine (100 mg) or placebo (lactose) 3 h prior to their habitual bedtime, and the remaining dose of caffeine or placebo (100 mg) was administered 1 h before bedtime. The dose was separated in two, so as to evaluate the effects of caffeine on vigilance (these data will be presented elsewhere). Each subject provided a saliva sample upon their arrival at the laboratory, 5 min before bedtime and the following morning, so as to evaluate salivary caffeine concentration. Polysomnographic and quantified sleep recording and analyses. Statistical analyses To evaluate group differences in salivary caffeine concentration, a three-way anova with one independent factor (age group: young and middle-aged) and two repeated measures (condition: placebo and caffeine; and moment: baseline, bedtime and waketime) was performed. As the morning measure was missing for two subjects (one young man and one young woman), this analysis was performed with the 22 remaining subjects. Two-way anovas with one independent factor (age group: young and middle-aged) and one repeated measure (condition: placebo and caffeine) were performed to evaluate group differences on habitual caffeine consumption and sleep variables as a function of experimental conditions. As no interaction involving gender and condition was found on sleep variables, data from men and women were pooled together. Because of an abnormal distribution, sleep latency and SWS (min) variables were log transformed. To evaluate the possible impact of habitual caffeine consumption on sleep during baseline and the effects of caffeine, Pearson correlations were performed, after controlling for the effects of age, between habitual caffeine consumption and PSG sleep variables in the placebo condition, and between habitual caffeine consumption and the percentage of change of sleep parameters between the placebo and caffeine conditions (placebo)caffeine/placebo ·100). To evaluate topographic differences in sleep EEG spectral power, spectral power of homologous derivations of the two hemispheres were averaged, and analyses were performed on five different topographic regions: prefrontal (PF), frontal, central, parietal and occipital. The effects of caffeine on sleep EEG spectral power were evaluated using a three-way anova with one independent factor (age group: young and middleaged) and two repeated factors (condition: placebo and caffeine; and sleep cycle: cycle 1, cycle 2 and cycle 3) for each topographic region independently. Because of artefacts in the data, five subjects (two young and three middle-aged) were excluded from PF derivation analyses, one middle-aged subject was excluded from the frontal derivation analyses, and four subjects (three young and one middle-aged) were excluded from occipital derivation analyses. Huynd–Feld-adjusted univariate tests were used for the repeated measures. Tukey HSD post hoc tests were used to decompose cycle effects between derivations, while deviation contrasts were used when a significant interaction with the factor cycle was found. Simple main effect analyses were used to decompose any other interaction effect and statistical significance was set at a probability level of 0.05. Analyses were performed on log transformed spectral power.
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How many outcome-specific endpoints are evaluated? 1
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) sleep
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List additional health endpoints (separately).
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List additional health endpoints (separately)
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Notes sleep variables included sleep latency, efficiency, and duration
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Clinical
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Physiological 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? NCT
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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 polysomnograph
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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.) lactose placebo (no caffeine) vs 200 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). Table 2 presents sleep variables (mean and SEM) for young and middle-aged subjects. F- and P-values are also presented. Compared with the placebo condition, caffeine lengthened sleep latency, reduced sleep efficiency, and decreased sleep duration in both age groups. In addition, caffeine decreased the amount of stage 2 sleep. Compared with young subjects, middle-aged subjects showed earlier waketime, lower sleep efficiency, shorter sleep duration and less SWS (i.e. stages 3 and 4). No interactions between age group and condition were found for any of the PSG sleep variables. After controlling for the effects of age, no significant relationships were found between habitual caffeine consumption and the sleep variables in the placebo condition. No significant correlations were found between habitual caffeine consumption and the modification of the sleep parameters in the caffeine condition.
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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? Caffeine ingested before bedtime had disruptive effects on sleep variables. More specifically, caffeine increased sleep latency and decreased sleep efficiency, total sleep time and the number of minutes spent in stage 2 sleep. Importantly, these effects were observed in moderate caffeine consumers while they maintained their habitual caffeine consumption, showing that sleep remains sensitive to the effects of caffeine despite moderate caffeine consumption habits. This result supports the notion that tolerance is incomplete in this population (Fredholm et al., 1999)
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What were the sources of funding? This research was supported by scholarships and grants (to Carrier) from the Canadian Institutes of Health Research (CIHR), the Fonds de recherche en Sante´ du Que´bec (FRSQ) and the Natural Sciences and Engineering Research Council of Canada (NSERC) as well as students fellowships from FRSQ (to Drapeau), NSERC (to Hamel-He´bert) and CIHR (to Robillard).
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What conflicts of interest were reported? none reported
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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.  sleep - LOAEL = 200 mg/day (negatively effected sleep efficiency and duration and increased latency to fall asleep)
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Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot. single dose adverse effects seen when a split dose, 100 mg caffeine 3 hours before bed and 100 mg 1 hour before bed were administered
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What is the importance of the study with respect to the adverseness of the outcome? Important
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