标题： 空气质量与心肌梗死的荟萃分析评价，案例研究 显示英文标题

标题： Evaluation of a meta-analysis of air quality and heart attacks, a case study

摘要： 人们普遍认为，观察性研究中的结论往往无法被复制。 进行了一项探索性研究，以评估用于短期空气质量-心肌梗死风险荟萃分析的基础研究的可靠性，并判断使用观察性研究数据的荟萃分析中的统计证据的可靠性。 一项高度引用的荟萃分析论文被用作案例研究，该论文探讨短期空气质量暴露是否引发心肌梗死。 该论文考虑了六种空气质量成分——一氧化碳、二氧化氮、二氧化硫、直径为10微米和2.5微米的颗粒物（PM10和PM2.5）以及臭氧。 估计了34篇基础论文中涉及的可能问题和统计模型的数量，并为每种空气成分构建了p值图，以评估从基础论文中使用的p值的效果异质性。 基础论文中的分析搜索空间（可能的统计检验数量）很大，中位数为12,288，四分位距：2,496至58,368，与实际呈现的统计检验结果相比。 从基础论文中获取的统计检验结果可能无法为荟萃分析提供无偏的效果度量。 六种空气成分的p值图形状与在几篇基础论文中通过分析操作获得小p值的可能性一致。 结果表明，荟萃分析中使用的是异质的、研究人员生成的p值，而不是空气质量真实效应的无偏证据。 我们得出结论，这项荟萃分析并未提供空气质量成分与心肌风险相关性的可靠证据。 显示英文摘要

摘要： It is generally acknowledged that claims from observational studies often fail to replicate. An exploratory study was undertaken to assess the reliability of base studies used in meta-analysis of short-term air quality-myocardial infarction risk and to judge the reliability of statistical evidence from meta-analysis that uses data from observational studies. A highly cited meta-analysis paper examining whether short-term air quality exposure triggers myocardial infarction was evaluated as a case study. The paper considered six air quality components - carbon monoxide, nitrogen dioxide, sulfur dioxide, particulate matter 10 and 2.5 micrometers in diameter (PM10 and PM2.5), and ozone. The number of possible questions and statistical models at issue in each of 34 base papers used were estimated and p-value plots for each of the air components were constructed to evaluate the effect heterogeneity of p-values used from the base papers. Analysis search spaces (number of statistical tests possible) in the base papers were large, median of 12,288, interquartile range: 2,496 to 58,368, in comparison to actual statistical test results presented. Statistical test results taken from the base papers may not provide unbiased measures of effect for meta-analysis. Shapes of p-value plots for the six air components were consistent with the possibility of analysis manipulation to obtain small p-values in several base papers. Results suggest the appearance of heterogeneous, researcher-generated p-values used in the meta-analysis rather than unbiased evidence of real effects for air quality. We conclude that this meta-analysis does not provide reliable evidence for an association of air quality components with myocardial risk.