Research Unit for Dietary Studies, The Parker Institute, Bispebjerg and Frederiksberg Hospital, 2000 Frederiksberg, Denmark.
Research Group for Social and Clinical Pharmacy, Department of Pharmacy, University of Copenhagen, 2100 Copenhagen, Denmark.
Nutrients. 2021 Oct 14;13(10):3601. doi: 10.3390/nu13103601.
Based on a large volume of observational scientific studies and many summary papers, a high consumption of meat and processed meat products has been suggested to have a harmful effect on human health. These results have led guideline panels worldwide to recommend to the general population a reduced consumption of processed meat and meat products, with the overarching aim of lowering disease risk, especially of cancer. We revisited and updated the evidence base, evaluating the methodological quality and the certainty of estimates in the published systematic reviews and meta-analyses that examined the association between processed meat consumption and the risk of cancer at different sites across the body, as well as the overall risk of cancer mortality. We further explored if discrepancies in study designs and risks of bias could explain the heterogeneity observed in meta-analyses. In summary, there are severe methodological limitations to the majority of the previously published systematic reviews and meta-analyses that examined the consumption of processed meat and the risk of cancer. Many lacked the proper assessment of the methodological quality of the primary studies they included, or the literature searches did not fulfill the methodological standards needed in order to be systematic and transparent. The primary studies included in the reviews had a potential risk for the misclassification of exposure, a serious risk of bias due to confounding, a moderate to serious risk of bias due to missing data, and/or a moderate to serious risk of selection of the reported results. All these factors may have potentially led to the overestimation of the risk related to processed meat intake across all cancer outcomes. Thus, with the aim of lowering the risk of cancer, the recommendation to reduce the consumption of processed meat and meat products in the general population seems to be based on evidence that is not methodologically strong.
基于大量观察性科学研究和许多综述论文，高肉类和加工肉类产品的消费被认为对人类健康有害。这些结果导致全球指南制定小组建议一般人群减少加工肉类和肉类产品的消费，主要目的是降低疾病风险，尤其是癌症风险。我们重新审查和更新了证据基础，评估了已发表的系统评价和荟萃分析中评估加工肉类消费与不同身体部位癌症风险之间关联以及总体癌症死亡率的方法学质量和估计的确定性。我们还进一步探讨了研究设计和偏倚风险的差异是否可以解释荟萃分析中观察到的异质性。总的来说，之前发表的大多数系统评价和荟萃分析在检查加工肉类消费与癌症风险之间的关系时存在严重的方法学局限性。许多研究缺乏对所纳入的原始研究方法学质量的适当评估，或者文献检索不符合系统和透明所需的方法学标准。这些综述中纳入的原始研究存在暴露分类错误的潜在风险、由于混杂导致的严重偏倚风险、由于数据缺失导致的中度至严重偏倚风险以及/或报告结果选择的中度至严重偏倚风险。所有这些因素都可能导致与所有癌症结局相关的加工肉类摄入风险被高估。因此，为了降低癌症风险，建议一般人群减少加工肉类和肉类产品的消费，这似乎是基于方法学上不强的证据。
