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. 2021 Jul 22;4:114. doi: 10.1038/s41746-021-00486-5

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© The Author(s) 2021

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

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Fig. 1 — This flowchart shows the number of records identified from the search (7855 non-duplicative records), the number of records excluded based on title and abstract (7448), and the number of studies excluded based on full article review (378), and the reasons for exclusions. Twenty-nine research articles (about 25 studies) were included in the analysis.