BackgroundThe impact factor (IF), as the most important criterion for journal’s quality measurement, is affected by the self-citation and number of publications in each journal.ObjectivesTo find out the relationship between the number of publications and self-citations in a journal, and their correlations with IF.Materials and MethodsSelf-citations and impact factors of nine top gastroenterology and hepatology journals were assessed during the seven recent years (2005-2011) through Journal Citation Reports (JCR, ISI Thomson Reuters).ResultsAlthough impact factors of all journals increased during the study, five out of nine journals increased the number of publications from 2005 to 2011. There was an increase in self-citation only in the journal of HEPATOLOGY (499 in 2005 vs. 707 in 2011). Impact factors of journals (6.5 ± 3.5) were positively correlated with total number of publications (248.6 ± 91.7) (R: 0.688, P < 0.001). Besides, the self-citation rate (238.73 ± 195.317) was highly correlated with total number of publications in each journal (248.6 ± 91.7) (R: 0.861, P < 0.001). On the other hand, impact factor without self-citation (6.08 ± 3.3) had a correlation (R: 0.672, P < 0.001) with the number of published items (248.6 ± 91.7).ConclusionsThe number of articles and self-citation have definite effects on IF of a journal and because IF is the most prominent criterion for journal’s quality measurement, it would be a good idea to consider factors affecting on IF such as self-citation.
Studies revealed an association between vitamin D deficiency and the frequency of cardiovascular diseases and their risk factors. This review is aimed at summarizing evidence for the association of vitamin D deficiency and vitamin D supplementation with the risk of cardiovascular diseases. The data was collected by surfing the Pubmed, Cochrane Central Registry and EMBASE databases for appropriate and related studies. Search terms included: "Vitamin D", "cardiovascular diseases", "CVD", "calcitriol" and "1,25-dihydroxy vitamin D". The abstracts of the discovered articles were reviewed, and the full texts of the articles that met the criteria were then evaluated to be used for the study. The large number of clinical trials, cross-sectional, prospective and systematic review studies are evidence that vitamin D deficiency is associated with most cardiovascular disease (CVD) risk factors and with the pathogenesis of CVD. However, with regard to the clinical trial studies evaluated in this work, vitamin D supplementation did not decrease the occurrence of cardiovascular events.
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