关键词：临床医学;流行病学;图;健康状况;地图;营养;营养;随机对照试验(相关的),统计数据
摘 要：In nutrition, there are several examples of discordance between the results of observational studies and of randomized controlled trials (RCTs). To provide empirical data on how often the summary results of epidemiological studies and of RCTs are concordant, and to explore whether the probability of concordant findings is associated with quantifiable metrics of citation maps formed between studies belonging to the evidence base of the nutrient-outcome association at hand. Citation maps are an objective representation of the translational paths in each association, and may be a surrogate of the maturity of the relevant evidence base. We searched MEDLINE to identify meta-analyses of RCTs or of epidemiological studies on the association between nutrients and health outcomes. Summary findings from both research designs that were statistically significant and in the same direction were considered qualitatively concordant. We also calculated the statistical significance of the difference in the summary effects from epidemiological studies and from RCTs (a measure of quantitative concordance). For each nutrient-outcome association we defined an evidence base including all publications identifiable by MEDLINE searches on the nutrient and outcome of interest and constructed citation maps of all articles in the evidence base that were cited by the epidemiological studies or the RCTs in the meta-analyses, either directly, or through one or more intermediary papers. We then quantified the size of the graphs (number of vertices and citation relationships), and their connectivity (density of citation relationships, mean hub and authority scores, and mean number of citations made or received over the included papers). We tested for associations between these metrics and the probability that the summary results from epidemiological studies and from RCTs are concordant between them.