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<front>
<journal-meta>
<journal-id journal-id-type="publisher-id">Front. Endocrinol.</journal-id>
<journal-title>Frontiers in Endocrinology</journal-title>
<abbrev-journal-title abbrev-type="pubmed">Front. Endocrinol.</abbrev-journal-title>
<issn pub-type="epub">1664-2392</issn>
<publisher>
<publisher-name>Frontiers Media S.A.</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.3389/fendo.2024.1346562</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Endocrinology</subject>
<subj-group>
<subject>General Commentary</subject>
</subj-group>
</subj-group>
</article-categories>
<title-group>
<article-title>Commentary: Causal effects of specific gut microbiota on bone mineral density: a two-sample Mendelian randomization study</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author" equal-contrib="yes">
<name>
<surname>Chen</surname>
<given-names>Jiahao</given-names>
</name>
<xref ref-type="author-notes" rid="fn003">
<sup>&#x2020;</sup>
</xref>
<uri xlink:href="https://loop.frontiersin.org/people/2590234"/>
<role content-type="https://credit.niso.org/contributor-roles/writing-original-draft/"/>
<role content-type="https://credit.niso.org/contributor-roles/investigation/"/>
</contrib>
<contrib contrib-type="author" equal-contrib="yes">
<name>
<surname>Guo</surname>
<given-names>Xiang</given-names>
</name>
<xref ref-type="author-notes" rid="fn003">
<sup>&#x2020;</sup>
</xref>
<role content-type="https://credit.niso.org/contributor-roles/investigation/"/>
<role content-type="https://credit.niso.org/contributor-roles/writing-original-draft/"/>
</contrib>
<contrib contrib-type="author" corresp="yes">
<name>
<surname>Song</surname>
<given-names>Hong</given-names>
</name>
<xref ref-type="author-notes" rid="fn001">
<sup>*</sup>
</xref>
<role content-type="https://credit.niso.org/contributor-roles/writing-review-editing/"/>
</contrib>
</contrib-group>
<aff id="aff1">
<institution>School of Basic Medicine, Zhejiang Chinese Medical University</institution>, <addr-line>Hangzhou, Zhejiang</addr-line>, <country>China</country>
</aff>
<author-notes>
<fn fn-type="edited-by">
<p>Edited by: Sadiq Umar, University of Illinois Chicago, United States</p>
</fn>
<fn fn-type="edited-by">
<p>Reviewed by: Zhiwei Li, Nanjing University of Chinese Medicine, China</p>
</fn>
<fn fn-type="corresp" id="fn001">
<p>*Correspondence: Hong Song, <email xlink:href="mailto:20021017@zcmu.edu.cn">20021017@zcmu.edu.cn</email>
</p>
</fn>
<fn fn-type="equal" id="fn003">
<p>&#x2020;These authors have contributed equally to this work and share first authorship</p>
</fn>
</author-notes>
<pub-date pub-type="epub">
<day>28</day>
<month>02</month>
<year>2024</year>
</pub-date>
<pub-date pub-type="collection">
<year>2024</year>
</pub-date>
<volume>15</volume>
<elocation-id>1346562</elocation-id>
<history>
<date date-type="received">
<day>29</day>
<month>11</month>
<year>2023</year>
</date>
<date date-type="accepted">
<day>31</day>
<month>01</month>
<year>2024</year>
</date>
</history>
<permissions>
<copyright-statement>Copyright &#xa9; 2024 Chen, Guo and Song</copyright-statement>
<copyright-year>2024</copyright-year>
<copyright-holder>Chen, Guo and Song</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/">
<p>This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.</p>
</license>
</permissions>
<related-article id="RA1" related-article-type="commentary-article" xlink:href="10.3389/fendo.2023.1178831" ext-link-type="doi">A Commentary on <article-title>Causal effects of specific gut microbiota on bone mineral density: a two-sample Mendelian randomization study</article-title> by Chen S, Zhou G, Han H, Jin J and Li Z (2023) <italic>Front. Endocrinol.</italic> 14:1178831. doi:&#xa0;<object-id>10.3389/fendo.2023.1178831</object-id>
</related-article>
<kwd-group>
<kwd>gut microbiota</kwd>
<kwd>bone mineral density</kwd>
<kwd>Mendelian randomization</kwd>
<kwd>Prevotella</kwd>
<kwd>allele</kwd>
</kwd-group>
<counts>
<fig-count count="0"/>
<table-count count="0"/>
<equation-count count="0"/>
<ref-count count="8"/>
<page-count count="2"/>
<word-count count="379"/>
</counts>
<custom-meta-wrap>
<custom-meta>
<meta-name>section-in-acceptance</meta-name>
<meta-value>Bone Research</meta-value>
</custom-meta>
</custom-meta-wrap>
</article-meta>
</front>
<body>
<sec id="s1" sec-type="intro">
<label>1</label>
<title>Introduction</title>
<p>Shuai Chen and his colleagues published a study titled &#x201c;Causal effects of specific gut microbiota on bone mineral density: a two-sample Mendelian randomization study&#x201d; in <italic>Frontiers in Endocrinology</italic> (<xref ref-type="bibr" rid="B1">1</xref>). The authors concluded, &#x201c;Our MR analysis also found that the abundance of Prevotella9 and Prevotellaceae was associated with high BMD at different sites. Consistent directional effects for all analyses were observed in both MR-Egger and weighted median methods, which suggests that Prevotella might be a promising target for osteoporosis prevention.&#x201d; We support and appreciate the authors&#x2019; work and agree with their conclusions. However, we have some concerns about their data and results. Here are some critical comments on these issues.</p>
<p>On the first line of Supplementary Table S1, the Effect allele and Other alleles were marked wrong. In the article of Qi Wang et&#xa0;al. (<xref ref-type="bibr" rid="B2">2</xref>&#x2013;<xref ref-type="bibr" rid="B4">4</xref>), the Effect_allele of rs182549 was C, and Other_allele was T, while in the author&#x2019;s article, the Effect_allele of rs182549 was T, and Other_allele was C. In short, &#x201c;Effect_allele&#x201d; and &#x201c;Other_allele&#x201d; should switch places in the Supplementary Table S1.</p>
<p>Under the subheading of Causal effect of the gut microbiota on forearm bone mineral density, this article first describes &#x201c;Genus Prevotella9 (&#x3b2; = 0.129, 95% CI: 0.007&#x2013;0.251, P = 0.039) were negatively associated with FA-BMD (Figure&#xa0;2)&#x201d;. Then, in <italic>Discussion</italic>, this article describes &#x201c;which suggests that Prevotella might be a promising target for osteoporosis prevention.&#x201d; There is an apparent inconsistency between the two accounts. &#x3b2; is the beta value, and exposure factors and outcomes are positively correlated when &#x3b2; is &gt;0 (<xref ref-type="bibr" rid="B5">5</xref>&#x2013;<xref ref-type="bibr" rid="B7">7</xref>). Hence, Prevotella9 was positively correlated with FA-BMD, which is consistent with the study of Liang Zhuang et&#xa0;al., &#x201c;Some short-chain fatty acids (SCFAs) producers, including Lactobacillus, Akkermansia, Prevotella, Alistipes, and Butyricicoccus, were reduced in patients with lower bone mass (LBM) and PMO.&#x201d; (<xref ref-type="bibr" rid="B8">8</xref>).</p>
<p>The study by Chen and his colleagues has helped us better understand the relationship between specific gut microbiota and bone mineral density. Still, it needs to be written more accurately to demonstrate the causal relationship between the gut microbiota and the risk of osteoporosis.</p>
</sec>
<sec id="s2" sec-type="author-contributions">
<title>Author contributions</title>
<p>JC: Writing &#x2013; original draft, Investigation. XG: Investigation, Writing &#x2013; original draft. HS: Writing &#x2013; review &amp; editing.</p>
</sec>
</body>
<back>
<sec id="s3" sec-type="funding-information">
<title>Funding</title>
<p>The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The study is funded by the Zhejiang Provincial Natural Science Foundation of China under Grant No. LGF20H270013; Postgraduate Research Fund Project of Zhejiang Chinese Medical University No. 2023YKJ20.</p>
</sec>
<sec id="s4" sec-type="COI-statement">
<title>Conflict of interest</title>
<p>The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.</p>
</sec>
<sec id="s5" sec-type="disclaimer">
<title>Publisher&#x2019;s note</title>
<p>All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.</p>
</sec>
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