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Study Title and Description

The association between coffee consumption and plasma total homocysteine levels: the "ATTICA" study.



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 The association between coffee consumption and plasma total homocysteine levels: the "ATTICA" study.
Author DB Panagiotakos,C Pitsavos,A Zampelas,A Zeimbekis,C Chrysohoou,L Papademetriou,C Stefanadis,
Country
Year 2004
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)? In this work we aimed to test the hypothesis of a dose – response relationship between plasma total homocysteine levels and coffee consumption in a population-based sample of cardiovascular disease-free adults.
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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) Population of the Study The "ATTICA" study7,8 is a health and nutrition survey, which is being carried out in the province of Attica (including 78% urban and 22% rural areas), of which Athens is the metropolis. The sampling was random, multistage, and based on the age and sex distribution of the province of Attica provided by the National Statistical Service (census of 2001). From May 2001 to December 2002, 4056 inhabitants from the this area were randomly selected to enter into the study. Among them, 1518 men (46 +/- 13 years old) and 1524 (45 +/- 13 years old) women agreed to participate (75% participation rate). Participants were interviewed by trained personnel (cardiologists, general practitioners, dietitians, and nurses) who used a standard questionnaire. Dietary Assessment Consumption of various foods were measured as average per week during the year previous to the study through a validated food – frequency questionnaire from the Unit of Nutritional Epidemiology of our Institute. All participants were asked to state their usual frequency of consumption of coffee over the previous year. Based on the distribution of coffee consumption, we categorized usual coffee consumption as: none, up to 100ml per day (rare consumption), 200–400ml per day (moderate consumption), or more than 500ml per day (heavy consumption). All reported types of coffee (instant coffee, "Greek" type, filtered, or "cappuccino") were adjusted for one cup (150ml) of coffee. We also took into account the consumption of filtered coffee, tea, and caffeine-containing drinks (such as Coca-Cola) or chocolate consumption. Cessation of coffee consumption during the previous year (in months of abstinence) was recorded and taken into account as a covariate for the analysis which followed. Biochemical Analyses During the enrollment, blood samples from the antecubital vein of all participants were collected between 08:00 and 10:00 h and after a 12-h overnight fast. Blood was collected into a glass tube without preservative (Vacutainer tube, Becton Dickinson, Franklin Lakes, NJ, USA) for serum lipids. The biochemical evaluation was carried out in the same laboratory than followed the criteria of the World Health Organization Lipid Reference Laboratories. The concentration of total homocysteine in plasma was estimated based on the technology of fluorescence polarization immunoassay (using an automatic analyzer from Abott Axsym, Munich Germany), which is a modified version of the fully automated column-switching high-performance liquid chromatography (HPLC) method. Demographic, clinical, and lifestyle characteristics The study questionnaire also included demographic characteristics, such as age, gender, financial status, education level, smoking status, and physical activity. Body mass index (BMI) was calculated as weight (in kg) divided by standing height (in m2). Obesity was defined as BMI _ 29.9kg/m2. Arterial blood pressure was measured three times at the right arm (using an ELKA aneroid sphygmomanometer, Von Schlieben, Munich, Germany), at the end of the physical examination with the subject in a sitting position for at least 30 min. Patients whose average blood pressure levels were greater or equal to 149/90mmHg or who were under antihypertensive medication were classified as hypertensives. Hypercholesterolemia was defined as total serum cholesterol levels greater than 200 mg/dl, or the use of lipidlowering agents and diabetes mellitus as a blood sugar level >125mg/dl, or the use of antidiabetic medication. Statistical Analysis Continuous variables are presented as mean value +/- standard deviation, while qualitative variables are presented as absolute and relative frequencies. Associations between categorical variables were tested by the used of contingency tables and calculation of the chi-square test. Correlations between homocysteine levels and other cofactors were evaluated by the calculation of Pearson’s correlation coefficient for the normally distributed variables and by the Spearman correlation coefficient for the skewed variables. Comparisons between normally distributed continuous variables and groups of coffee consumption were performed by multi-way analysis of covariance (ANCOVA), after testing for equality of variances (homoscedacity), and taking into account the effect of age, sex, BMI, smoking habits, physical activity, education status, food items consumed, and use of medication. In the case of asymmetric continuous variables the tested hypotheses were based on the calculations of the nonparametric test suggested by Kruskal and Wallis. Differences in homocysteine levels between subgroups of the participants according to coffee consumption were tested using post hoc analysis (after adjusting for multiple comparisons using the Bonferroni correction). Any interaction of coffee with the previously mentioned factors was assessed by calculation of the -2LogLikelihood ratio statistic between the model containing the interaction term and the main effects model. All the analyses applied in this work were stratified by gender. Finally, we also stratified our analysis by type of coffee consumed (filtered vs. unfiltered. All reported P values are based on two-sided tests and compared to a significance level of 5%. Statistical Package for Social Sciences software, version 11.0 (SPSS, Chicago, IL, USA) was used for all the statistical calculations.
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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) Plasma total homocysteine levels
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List additional health endpoints (separately). 2
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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? Cohort
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Randomized or Non-Randomized?
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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 The concentration of total homocysteine in plasma was estimated based on the technology of fluorescence polarization immunoassay (using an automatic analyzer from Abott Axsym, Munich Germany).
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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? Self-report
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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.) Non-coffee drinkers
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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) Age, gender, smoking habits, BMI, physical activity status, presence of hypertension and hypercholesterolemia, fruit and vegetable consumption, quantity of alcohol drinking, menopausal status, intake of caffeine-containing drinks, and months of abstinence from coffee drinking during the previous year
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What conflicts of interest were reported? No information provided
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Refid 15799175
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What were the sources of funding? The ATTICA study is supported by research grants from the Hellenic Cardiological Society (HCS2002) and the Hellenic Atherosclerosis Society (HAS2003).
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Results & Comparisons

No Results found.