Estimation of population attributable fraction (PAF) requires unbiased relative risk (RR) by using either Levin’s or Miettinen’s formula, on which decision depends on the available exposure information in reference group, not the types of studies. For ecological studies and studies with aggregated outcomes, once having unbiased RRs, Levin’s and Miettinen’s formulae would provide identical PAF estimates. PAF could also be applied to compare relative burdens of disease between countries across time, which is an additional information in consideration of country-level policies.

中文翻译：

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人口归因分数在生态学研究中的估计与应用

估计人口可归因分数（PAF）需要使用Levin或Miettinen公式进行无偏的相对风险（RR），该公式的决定取决于参考组中可用的暴露信息，而不是研究类型。对于生态研究和具有总计结果的研究，一旦具有无偏的RR，Levin和Miettinen的公式将提供相同的PAF估计值。PAF还可以用于比较国家之间一段时间内疾病的相对负担，这是考虑到国家级政策的补充信息。