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Reporting quality and risk of bias of systematic reviews of ultra-processed foods: a methodological study

European Journal of Clinical Nutrition volume 78, pages 171–179 (2024)Cite this article

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Abstract

A dramatic shift in the global food system is occurring with the rapid growth of ultra-processed foods (UPFs) consumption, which poses potentially serious health risks. Systematic review (SR) method has been used to summarise the association between UPF consumption and multiple health outcomes; however, a suboptimal-quality SR may mislead the decision-making in clinical practices and health policies. Therefore, a methodological review was conducted to identify the areas that can be improved regarding the risk of bias and reporting quality of relevant SRs. Systematic searches to collect SRs with meta-analyses of UPFs were performed using four databases from their inception to April 14, 2023. The risk of bias and reporting quality were evaluated using ROBIS and PRISMA 2020, respectively. The key characteristics of the included SRs were summarised descriptively. Excel 2019 and R 4.2.3 were used to analyse the data and draw graphs. Finally, 16 relevant SRs written in English and published between 2020 and 2023 in 12 academic journals were included. Only one SR was rated as low risk of bias, and the others were rated as higher risk of bias mainly because the risk of bias in the original studies was not explicitly addressed when synthesising the evidence. The reporting was required to be advanced significantly, involving amendments of registration and protocol, data and analytic code statement, and lists of excluded studies with justifications. The reviews’ results could improve the quality, strengthen future relevant SRs’ robustness, and further underpin the evidence base for supporting clinical decisions and health policies.

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Fig. 1: PRISMA flow diagram.
Fig. 2: Geographic distribution of the included systematic reviews.
Fig. 3: Radar plot of reporting quality.

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Data availability

The datasets used and analysed in the current methodological systematic review are presented in the text and appendix.

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Funding

This work was supported by the Major Program of the National Science Found of China “Research on the Theoretical System, International Experience and Chinese Path of Evidence-based Social Science” [Grant number: 19ZDA142] and A clinical comprehensive evaluation of traditional Chinese medicine in the treatment of hypertension [Grant number: 22JR5RA510]. The funder did not play any role in each process of this review.

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Author notes

  1. These authors contributed equally: Ziyi Wang, Yan Wang, Wenru Shang.

Authors and Affiliations

  1. Health Technology Assessment Center, Evidence-Based Social Science Research Center, School of Public Health, Lanzhou University, Lanzhou, 730000, China

    Ziyi Wang, Wenru Shang, Wendi Liu, Cui Lu, Jiayi Huang, Kehu Yang & Xiuxia Li

  2. Evidence Based Medicine Center, School of Basic Medical Sciences, Lanzhou University, Lanzhou, 730000, China

    Ziyi Wang, Wenru Shang, Wendi Liu, Cui Lu, Jiayi Huang, Kehu Yang & Xiuxia Li

  3. Key Laboratory of Evidence Based Medicine and Knowledge Translation of Gansu Province, Lanzhou, 730000, China

    Ziyi Wang, Wenru Shang, Wendi Liu, Cui Lu, Jiayi Huang, Kehu Yang & Xiuxia Li

  4. Shangluo Central Hospital of Shaanxi Provincial, Shangluo, 726000, China

    Yan Wang

  5. Institute of Basic Research in Clinical Medicine, China Academy of Chinese Medical Sciences, 100700, Beijing, China

    Chao Lei, Zijia Chen, Zhifei Wang & Cuncun Lu

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Contributions

CL designed this study. ZW and YW performed the search. ZW and WS selected the literature. ZW and YW collected data. WS and WL rechecked data. ZW and CL assessed the quality. CL, ZW, YW, and WS performed analysis. ZW, CL, YW, and WS drafted the manuscript. XL, KY, WL, LC, JH, CL, ZC, and ZW revised the manuscript. All authors approved the final version of this manuscript.

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Correspondence to Xiuxia Li or Cuncun Lu.

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Wang, Z., Wang, Y., Shang, W. et al. Reporting quality and risk of bias of systematic reviews of ultra-processed foods: a methodological study. Eur J Clin Nutr 78, 171–179 (2024). https://doi.org/10.1038/s41430-023-01383-8

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