Maternal pre-pregnancy body mass index and related factors: A cross-sectional analysis from the Japan Environment and Children’s Study

Yasuaki Saijo; Eiji Yoshioka; Yukihiro Sato; Yuki Kunori; Tomoko Kanaya; Kentaro Nakanishi; Yasuhito Kato; Ken Nagaya; Satoru Takahashi; Yoshiya Ito; Hiroyoshi Iwata; Takeshi Yamaguchi; Chihiro Miyashita; Sachiko Itoh; Reiko Kishi; the Japan Environment and Children’s Study (JECS) Group

doi:10.1371/journal.pone.0304844

Peer Review History

Original SubmissionJanuary 17, 2024
10 Apr 2024 Decision Letter - Malshani Lakshika Pathirathna, Editor PONE-D-24-01959Maternal pre-pregnancy body mass index and related factors: a cross-sectional analysis from the Japan Environment and Children’s StudyPLOS ONE Dear Dr. Saijo Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by May 25 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols. We look forward to receiving your revised manuscript. Kind regards, Malshani Lakshika Pathirathna, PhD Academic Editor PLOS ONE Journal Requirements: When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for stating the following financial disclosure: "This study was funded by the Ministry of Environment, Japan. The findings and conclusions of this article are solely the responsibility of the authors and do not represent the government's official views." Please state what role the funders took in the study. If the funders had no role, please state: "The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript." If this statement is not correct you must amend it as needed. Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf. 3. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please move it to the Methods section and delete it from any other section. Please ensure that your ethics statement is included in your manuscript, as the ethics statement entered into the online submission form will not be published alongside your manuscript. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Partly ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: No Reviewer #2: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: There are some spelling and grammatical errors in the document, please review: e.g. Serioeconomic status page 5, line 73 I am also uncomfortable with the term 'inappropriate' for anyone who does not have a normal BMI. Perhaps a better way to state this would be those without a normal BMI. This is in line with Equality, Diversity and Inclusivity terms of peer-reviewed research in current times. It is very interesting to see such a dichotomy in results from the Japanese population with such a high number of 'normal BMI' participants. I think this is worth highlighting in the discussion with some references on global values. While it cannot be generalized, it is a result that is uncommon. I felt that the population of still smoking and quitting at early pregnancy should be divided as the biochemical differences in these women are so different. It would add value to the paper. It is also important to talk about the J shaped RRs for some exposures such as smoking and BMI. Otherwise a well written paper with minor errors. Reviewer #2: Dear Editor, Thanks for inviting me to review this study. The study was interesting to read and had some relevant information that will add to the existing literature. However, it is not suitable for publication in its current form. Please find my comments below. Introduction There was no clear justification for the need for the study. Method The study lacked clear step by step procedure used for data collection. It is not clear how the hospitals included in the study were selected. It is not clear if consent was obtained, or the type of consent obtained prior to data collection. There was no clear information about inclusion and exclusion criteria. How were the pregnant women recruited? It is not clear if the study was done retrospectively. There was no clear information about the questionnaire used in the study, how was developed? was it validated and how it was validated. What confounding factors were detected and how were they managed? It is not clear how pre pregnancy BMI of the pregnant women were obtained since they were already pregnant and only pregnant women were included in the study? Was it a self-reported BMI or were participants’ BMI taken before they got pregnant? The authors failed to provide information on how the parameter including BMI, Height and weight were obtained from the participants. Including duration of smoking could have benefitted the study. Result The tables are two long could have been better presented with graphs. Recommendation Overall, the study has large sample size and some novel information that could add to literature, but it is not suitable for publication in its current form. There is a need to review the methodology. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: Yes: Nasloon Ali Reviewer #2: Yes: Ngozika Ezinne ******** [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0304844.r001
Revision 1
30 Apr 2024 Author Response #Answer to Journal Requirements: When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf [Response] We revised the manuscript to comply with PLOS ONE's file naming and style requirements. 2. Thank you for stating the following financial disclosure: "This study was funded by the Ministry of Environment, Japan. The findings and conclusions of this article are solely the responsibility of the authors and do not represent the government's official views." Please state what role the funders took in the study. If the funders had no role, please state: "The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript." If this statement is not correct you must amend it as needed. Please include this amended Role of Funder statement in your cover letter; we will change the online submission form on your behalf. [Response] The statement was changed as follow, and it was included in the cover letter. “This study was funded by the Ministry of Environment, Japan. The findings and conclusions of this article are solely the responsibility of the authors and do not represent the government's official views. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.” 3. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please move it to the Methods section and delete it from any other section. Please ensure that your ethics statement is included in your manuscript, as the ethics statement entered into the online submission form will not be published alongside your manuscript. [Response] The ethics statement was mentioned only in the Method section, and not in any other part of the document. #Answer to Reviewers' comments: Reviewer #1: There are some spelling and grammatical errors in the document, please review: e.g. Serioeconomic status page 5, line 73 I am also uncomfortable with the term 'inappropriate' for anyone who does not have a normal BMI. Perhaps a better way to state this would be those without a normal BMI. This is in line with Equality, Diversity and Inclusivity terms of peer-reviewed research in current times. [Response] I have made sure to check all the spellings thoroughly. Additionally, I have replaced every instance of the word 'inappropriate' with 'not having normal', and made other necessary changes wherever applicable. It is very interesting to see such a dichotomy in results from the Japanese population with such a high number of 'normal BMI' participants. I think this is worth highlighting in the discussion with some references on global values. While it cannot be generalized, it is a result that is uncommon. [Response] P21L286: “However, it should be noted that the findings from Japan, which has a relatively high number of underweight women and is the only high-income country with a high prevalence of underweight individuals, may not be applicable to low-income countries or countries with a low prevalence of underweight women [50].” was added. A new reference was added as the 50th reference: NCD Risk Factor Collaboration (NCD-RisC). Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults. Lancet. 2024 Mar 16;403(10431):1027-1050. doi: 10.1016/S0140-6736(23)02750-2. Epub 2024 Feb 29. I felt that the population of still smoking and quitting at early pregnancy should be divided as the biochemical differences in these women are so different. It would add value to the paper. It is also important to talk about the J shaped RRs for some exposures such as smoking and BMI. [Response] Since smoking cessation after pregnancy occurred after the outcome measure for pre-pregnancy BMI, we considered factors that occurred after the outcome measure should not be treated as causal factors. Otherwise a well written paper with minor errors. [Response] Thank you for your valuable and constructive comments. Reviewer #2: Dear Editor, Thanks for inviting me to review this study. The study was interesting to read and had some relevant information that will add to the existing literature. However, it is not suitable for publication in its current form. Please find my comments below. Introduction There was no clear justification for the need for the study. [Response] P4L85: “Obesity and being underweight during pregnancy increase the risk of adverse obstetric outcomes. Identifying related factors can help prevent these outcomes.” was added. Method The study lacked clear step by step procedure used for data collection. [Response] Details of the data collection procedure were added. Please see the following responses. It is not clear how the hospitals included in the study were selected. [Response] P6L115: “Recruitment activities were conducted at healthcare providers and local government facilities to identify eligible women in the study areas. However, the recruitment was not entirely random. Our team made every effort to reach out to as many eligible women in the study areas as possible. The child coverage was estimated to be approximately 45% of the studied areas [28, 29].” was added. It is not clear if consent was obtained, or the type of consent obtained prior to data collection. [Response] P5L104: “and written informed consent was obtained from all participants prior to data collection.” was added. There was no clear information about inclusion and exclusion criteria. [Response] P4L104: “Written informed consent was obtained from all participants prior to data collection. The inclusion criteria were as follows: 1) Pregnant women whose expected delivery dates were between August 2011 and March 2014, 2) pregnant women who resided in one of the study areas selected by the Regional Centres at the time of recruitment, and who were expected to reside continually in Japan for the foreseeable future, and 3) pregnant women who visited a cooperating health care provider selected by the Regional Centre or local government offices to obtain a Mother-Child Health Handbook in a study area during the recruiting period. The exclusion criteria were as follows: 1) Pregnant women who did not consent to participate in the study, 2) pregnant women who showed difficulty in comprehending the study procedures or filling out the questionnaires without support, and 3) pregnant women who were reportedly not accessible at the time of delivery (e.g., women who planned to give birth outside the study area).” was added. How were the pregnant women recruited? [Response] Please see the above responses. It is not clear if the study was done retrospectively. [Response] P5L101: “The protocol for analyzing the data in this study was prepared after the relevant data was collected.” was added. There was no clear information about the questionnaire used in the study, how was developed? was it validated and how it was validated. [Response] P20L297 “Finally, the variables data were obtained from self-administered questionnaires. The validities of the used questions were directly evaluated, but questions about smoking habits and alcohol consumption were based on the question used in the Japan Public Health Centre-based prospective Study for the Next Generation [JPHC-NEXT] [53], and occupation in early pregnancy was based on the 2009 Japan Standard Occupational Classification [28].” was added. A new reference was added: Yokoyama Y, Takachi R, Ishihara J, Ishii Y, Sasazuki S, Sawada N, Shinozawa Y, Tanaka J, Kato E, Kitamura K, Nakamura K, Tsugane S. Validity of Short and Long Self-Administered Food Frequency Questionnaires in Ranking Dietary Intake in Middle-Aged and Elderly Japanese in the Japan Public Health Center-Based Prospective Study for the Next Generation (JPHC-NEXT) Protocol Area. J Epidemiol. 2016 Aug 5;26(8):420-32. doi: 10.2188/jea.JE20150064. What confounding factors were detected and how were they managed? [Response] P7L157: “Maternal age and parity were selected as covariates, and data were transcribed from the medical records. Maternal age was categorized as <19, 20–24, 25–29, 30–34, 35–39, or >40 years, and parity was ranked as zero, one, two, or more.” was changed to “Maternal age and parity were selected as covariates (confounders) based on previous research on pregnant women [17, 32], and data were transcribed from the medical records. Maternal age was categorized as <19, 20–24, 25–29, 30–34, 35–39, or >40 years, and parity was ranked as zero, one, two, or more.” P8L169: “The models included educational attainment, household income, marital status, occupational status, smoking status, age, and parity.” was changed to “The models included educational attainment, household income, marital status, occupational status, smoking status, and covariates (age and parity).” It is not clear how pre pregnancy BMI of the pregnant women were obtained since they were already pregnant and only pregnant women were included in the study? Was it a self-reported BMI or were participants’ BMI taken before they got pregnant? The authors failed to provide information on how the parameter including BMI, Height and weight were obtained from the participants. [Response] P6L133: “Maternal height and pre-pregnancy weight were obtained from medical records. If missing, these data were obtained from self-reports.” was added. Including duration of smoking could have benefitted the study. [Response] Because this paper dealt with many variables, we considered that further categories of smoking would lead to an incomprehensible table, and the number of each category would be rather small. So, we did not conduct a further analysis of the smoking duration. Result The tables are two long could have been better presented with graphs. [Response] We would like to present precise 95% confidence intervals. Further, to compare with two previous studies about pregnant women and BMI which had a table of main results, we considered that the current table was more appropriate for this paper. Recommendation Overall, the study has large sample size and some novel information that could add to literature, but it is not suitable for publication in its current form. There is a need to review the methodology. [Response] Thank you for your valuable and constructive comments. We amended the method section according to the reviewers’ comments as above. Attachments Attachment Submitted filename: PLOSOne_answer_to_reviewers_20240430.docx https://doi.org/10.1371/journal.pone.0304844.r002
21 May 2024 Decision Letter - Malshani Lakshika Pathirathna, Editor Maternal pre-pregnancy body mass index and related factors: a cross-sectional analysis from the Japan Environment and Children’s Study PONE-D-24-01959R1 Dear Prof. Yasuaki Saijo, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager® and clicking the ‘Update My Information' link at the top of the page. If you have any questions relating to publication charges, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Malshani Lakshika Pathirathna, PhD Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #1: All comments have been addressed Reviewer #2: All comments have been addressed ******** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: Yes Reviewer #2: Yes ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes ****** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: Thank you for your responses. I believe you have answered my questions appropriately. I find the article sound for publication. Reviewer #2: (No Response) ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: No Reviewer #2: Yes: Dr Ngozika Esther Ezinne ******** https://doi.org/10.1371/journal.pone.0304844.r003
Formally Accepted
24 May 2024 Acceptance Letter - Malshani Lakshika Pathirathna, Editor PONE-D-24-01959R1 PLOS ONE Dear Dr. Saijo, I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team. At this stage, our production department will prepare your paper for publication. This includes ensuring the following: * All references, tables, and figures are properly cited * All relevant supporting information is included in the manuscript submission, * There are no issues that prevent the paper from being properly typeset If revisions are needed, the production department will contact you directly to resolve them. If no revisions are needed, you will receive an email when the publication date has been set. At this time, we do not offer pre-publication proofs to authors during production of the accepted work. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few weeks to review your paper and let you know the next and final steps. Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. If we can help with anything else, please email us at customercare@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Malshani Lakshika Pathirathna Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0304844.r004

Open letter on the publication of peer review reports

PLOS recognizes the benefits of transparency in the peer review process. Therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. Reviewers remain anonymous, unless they choose to reveal their names.

We encourage other journals to join us in this initiative. We hope that our action inspires the community, including researchers, research funders, and research institutions, to recognize the benefits of published peer review reports for all parts of the research system.

Learn more at ASAPbio .