1,721,002 research outputs found
Does drinking pattern modify the effect of alcohol on the risk of coronary heart disease? Evidence from a meta-analysis
No full textObjective: To evaluate the strength of the evidence provided by epidemiological literature investigating drinking pattern as effect modifier of alcohol intake on the risk of coronary heart disease (CHD). Design: Meta-analysis of observational studies. Data sources: Medline, citation tracking, from 1966 to 2006. Review methods: Original studies investigating the amount of alcohol intake, combined with the frequency of alcohol consumption and/or pattern of alcohol drinking affecting the risk of CHD were extracted. Among them, cohort and case-control studies reporting sufficient data to perform statistical analyses and using people who abstained from alcohol as the reference were included. Results: Six (4 cohort and 2 case-control) out of 118 studies reviewed met the inclusion criteria. Compared with those who abstained from alcohol, regular heavy drinkers and heavy irregular or binge drinkers showed significantly different pooled relative risks of 0.75 (95% confidence interval 0.64 to 0.89) and 1.10 (1.03 to 1.17) respectively. The dose-response relation between the amount of alcohol intake and CHD risk was significantly different in regular and irregular drinkers. A J-shaped curve, with nadir around 28 grams of alcohol per week, and last protective dose of 131 grams per week, was obtained including drinkers who consumed alcohol for 2 days a week or less. Conversely, in people who consumed alcohol for more than 2 days a week a significant protective effect was seen even when drinking high amounts of alcohol. Conclusion: This meta-analysis suggests that binge and heavy irregular drinking modify the favourable effect of alcohol intake on the CHD risk. However, this conclusion should be taken with caution because of the small number of studies considered
National cardiovascular prevention should be based on absolute disease risks, not levels of risk factors
No full textBackground: It has been shown that the prevention of multicausal diseases such as heart attack (at an individual level) should be guided by absolute risks rather than by the level of risk factors. Here, we show that an analogous argument should form the basis of population-level prevention. Methods: Estimates of age- and sex-specific means and standard deviations for systolic blood pressures and blood cholesterol concentrations and for deaths assigned to all vascular causes in 2002 were obtained from the World Health Organization for 25 current member states of the European Union, for the ages 30-69 years. Predicted effects of 5 mmHg reductions in mean systolic blood pressures and 0.5 mmol l-1 reductions in mean total blood cholesterol concentrations on deaths and years of life lost (YLL) per 100 000 person-years from vascular diseases were modelled using proportional risk coefficients from meta-analyses of cohort studies and randomized controlled trials. Results: Potential absolute benefits were strongly positively associated with current levels of absolute mortality risk: in the case of systolic blood pressure, predicted vascular deaths averted in the highest risk populations (Romania, Bulgaria) were over five times higher than in the lowest risk populations (Spain, France). Potential benefits were only weakly related to existing levels of the risk factor of interest. Conclusions: High-risk populations should give the highest priority to achieving favourable shifts in all modifiable risk factors. Irrespective of the level of any particular risk factor, the rewards will be greatest in these populations
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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