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Study Title and Description

Caffeine and intraocular pressure in a Nigerian population.



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 intraocular pressure in a Nigerian population.
Author OB Ajayi,MT Ukwade,
Country
Year 2001
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)? The goals of this study were to investigate the possible effect of consuming caffeinated coffee on IOP [intraocular pressure] of healthy young Nigerian university students (a subset of the Nigerian population that is involved in the consumption of coffee and thus caffeine) and to extend the finding to kola nuts and cocoa beans, which are widely consumed by a large portion of the general population in Nigeria and sub-Saharan Africa.
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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) Participants Potential participants for the study were recruited from the students of the University of Benin in Benin City, Nigeria. The students volunteered after they were informed about the scope of the study and given an explanation of the objective of the study. Hypertensive individuals were excluded from the study. Forty volunteers met the criteria for inclusion in the study. The participants, aged 20 to 27 years, were randomly assigned to an experimental (caffeine) and a control (decaffeinated) group. Each of these groups comprised 20 members reasonably balanced for age and gender. A total of 37 participants completed in the study and were included in the data analysis (18 in the experimental group and 17 in the control group). All participants abstained from caffeine-containing products, such as coffee, cola, and kola nuts, for at least 1 week before the acquisition of data. They also abstained from food and other beverages during the experimental interval. Procedure All data were collected between 9:00 AM and 3:30 PM, that is, midway between early morning and evening. A Perkins handheld applanation tonometer with a local anesthetic, 0.4% oxybuprocaine chlorohydrate, and sodium fluorescein strips were used each time during the study to measure IOP. The IOP readings were obtained before and 30, 60, and 90 minutes after the ingestion of coffee (caffeinated and decaffeinated).The experimental group received freshly prepared instant caffeinated coffee, whereas the control group was given instant decaffeinated coffee. The coffee was prepared with water as the solvent and was served in a teacup. In keeping with the local tradition, a cube of sugar was served with each cup of coffee. Typically, each member of the experimental group was made to sit down for the examination to be carried out. The blood pressure of each participant was taken twice using a sphygmomanometer and stethoscope, and the average of both readings was recorded. The participant then ingested 100 mL (approximately half a cup) of coffee prepared from 400 mg of caffeinated coffee measured with a Mettler’s weighing balance. The participants were not instructed on how fast they were to drink the coffee. Thus, the consumption time varied but did not exceed 2 minutes. Thereafter, IOP blood pressure were measured 30, 60, and 90 minutes after the ingestion of the coffee. The procedure was the same for the control group, but 400 mg of decaffeinated coffee was given to each participant. The participants and examiner were masked with regard to who drank caffeinated or decaffeinated coffee. An assistant, who also served the coffee, handled group assignment. There were several experimental sessions covering a period of approximately 3 months. Two or three subjects per group were examined during each session. We were unable to determine the caffeine content of the coffee served in this study, but mean values of caffeine in the literature range from 60 to 100 mg per 8 ounces (that is, per cup) for instant caffeinated coffee and 3 to 5 mg per 8 ounces for decaffeinated coffee. Thus, our half cup of saturated caffeinated coffee contained approximately 30 to 50 mg of caffeine and approximately 2 mg of caffeine in the decaffeinated coffee. Although decaffeinated coffee contains some caffeine, it was selected instead of water as a control because of its additional masking benefit. Also, because of the potential loss of participants to follow-up as a result of poor motivation, because the research did not receive financial support and had to rely on unpaid volunteers, we opted for the less ideal method of using separate experimental and control groups, rather than each participant serving as his or her own control.
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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) Blood pressure (SBP and DBP)
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List additional health endpoints (separately). 2 Intraocular pressure (IOP)
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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 A Perkins handheld applanation tonometer with a local anesthetic, 0.4% oxybuprocaine chlorohydrate, and sodium fluorescein strips were used to measure IOP. The blood pressure of each participant was taken twice using a sphygmomanometer and stethoscope, and the average of both readings was recorded.
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Caffeine (general) 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.) Decaffeinated coffee
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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 11219635
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What were the sources of funding? No information provided
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Results & Comparisons

No Results found.