Are early childhood stunting and catch-up growth associated with school age cognition?—Evidence from an Indian birth cohort

Beena Koshy; Manikandan Srinivasan; Sowmiya Gopalakrishnan; Venkata Raghava Mohan; Rebecca Scharf; Laura Murray-Kolb; Sushil John; Rachel Beulah; Jayaprakash Muliyil; Gagandeep Kang

doi:10.1371/journal.pone.0264010

Peer Review History

Original SubmissionJune 30, 2021
27 Sep 2021 Decision Letter - Seo Ah Hong, Editor Transfer Alert This paper was transferred from another journal. As a result, its full editorial history (including decision letters, peer reviews and author responses) may not be present. PONE-D-21-21418Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort PLOS ONE Dear Dr. Koshy, 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. ACADEMIC EDITOR: Thanks for sharing an interesting research with potentially a very useful addition to the literature. The reviewers request to address some critical points as follows and discuss these in depth by reviewing the literature. Additionally, regarding line 137-138, “These contradictory findings may be due to differing definitions and time periods studied [20],” although the authors discussed it in the discussion, you are requested to address in the introduction in terms of what your study add to the literature. Also the potential to recover from undernutrition to neurocognitive development need to be addressed. In Table 1, “Weight-for-age Z scores (HAZ)” needs to be changed to “Weight-for-age Z scores (WAZ)” Please submit your revised manuscript by Nov 11 2021 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. 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The Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequence for Child Health and Development Project (MAL-ED) is carried out as a collaborative project supported by the Bill and Melinda Gates Foundation, the Foundation for the NIH and the National Institutes of Health/Fogarty International Center (Grant number – GR-681) BK, LMK, RS, VRM, SJ, GK - GK lead Sponsor/Funder had no role in the study design, data collection and analysis, decision to publish or preparation of manuscript. b. The 9-year follow-up of the Mal-ed India cohort was supported by an Intermediate clinical and public health research fellowship awarded by the DBT/Wellcome Trust India Alliance to Dr. BK. (Fellowship grant number IA/CPHI/19/1/504611). Sponsor/Funder had no role in the study design, data collection and analysis, decision to publish or preparation of manuscript. 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Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: No 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: No ****** 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: This is an interesting paper and is potentially a very useful addition to the literature. The cohort, while small, has a high level of retention and a number of informative measures. It is great, for example, that there is data on maternal cognition. My concern with this paper is that the authors have not critically engaged with some of the key issues in the literature, despite mentioning a number, and these have significant implications for the interpretation of their results. -The authors note that the definition of catch up is a point of dispute in the literature, but do not explain why they selected the one that they used. The one used is a rather weak definition - children can be defined as having caught up even when falling behind in terms of CM deficits. Nonetheless, it is a commonly used definition and its use could be justified, but it does need to be justified and not used without question. -Stunting does not cause cognitive impairment, impairment and stunting are both indicators of malnutrition and possibly of lack of stimulation (and possible the combination of the two). As a result, any association between them needs to be carefully interpreted. The authors do not adequately cover this topic, which hinders the subsequent discussion of the results. -If the authors are going to make the case that their results imply that nutrition programmes are needed, then a fuller discussion of the adequacy of the controls in the regression is needed. As mentioned, the association with stunting may be a result of smaller children being protected by parents leading to under stimulation - this may not be resolved by a nutrition program. Similarly, smaller children may be held back from school entry as parents do not think they are ready. The association between stunting and cognitive performance may be a result of less exposure to schooling. -Do the authors think that catch up growth could indicate a recovery from earlier malnutrition leading to a similar catch up in cognition? Or that those who catch up avoid falling further behind, while those who remain stunted continue to fall behind? Their results could support either argument, but which argument is correct has important policy implications and this should be discussed. The authors from time to time slip into causal language, this should be avoided. The discussion on the importance of the first 1,000 days is a little unclear and could be improved. It is the pace and foundational nature of development in that period which is critical and this does not come through enough. Overall the paper is well written, but there are a few places which would benefit from a careful edit. Minor comments: Why report weight if you don't use it? Just for context? The top third based on WAMI can hardly be called high SES given the selection process. Would relatively high not be better? When was the WAMI measure taken? What the implications of only using one time point? Did those who exhibited catch up also see an improvement in their SES which might explain the better cognitive scores? Reviewer #2: Thank you for a very interesting study. Overall, the study is well conducted. There are a few comments and editorial as below. 1. Table 4: on the PIQ, it is shown that stunting at 2 y, though with a catch-up at 5 y had 5.77 PIQ less than normal children, but the children who stunted at 2 & 5 who only caught-up at 9 had much better PIQ than normal, than children who were already catch-up since 2y and those persisted till 9 y. What could explain such a pattern? Please add discussion. 2. Lines 365-366 & reference 17: Did children who received intervention were during older childhood (e.g., early school-age) and hence, the damage on cognition could have occurred since early age, aside from possible short duration of intervention? Please consider. 3. Editorial errors: a. Line 116, Introduction: ‘…. (HAZ) <2 on WHO…’, should this read ‘…. (HAZ) <-2 SD…’? b. Line 351 ‘A unit increase in HAZ <2 Y…’, suggest to read, ‘A unit increase in HAZ at <2 y of age..’ ****** 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: No Reviewer #2: Yes:** Pattanee Winichagoon [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/. 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Revision 1
12 Nov 2021 Author Response KINDLY SEE THE ATTACHED FILE To The reviewers PLOS One Re: PONE-D-21-21418 - Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort Dear reviewers, Thank you for reviewing our manuscript titled “Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort”. Author’s responses are provided below Comments Authors’ response Page number; line number Academic Editor 1. Additionally, regarding line 137-138, “These contradictory findings may be due to differing definitions and time periods studied [20],” although the authors discussed it in the discussion, you are requested to address in the introduction in terms of what your study add to the literature. Thank you. Suggested change has been made. 6; line 142-147 2. Also the potential to recover from undernutrition to neurocognitive development need to be addressed. Refer to the response to comment no. 1 6; line 142-147 3. In Table 1, “Weight-for-age Z scores (HAZ)” needs to be changed to “Weight-for-age Z scores (WAZ)” Thank you. Changed to WAZ Table 1 4. Financial statement Deleted from Title page section Cover letter 5. Competing interest No competing interest Deleted from Title page section Cover letter 6. Data Minimal anonymized data set is uploaded Supplementary file 7. Ethics statement – Mention only in manuscript Deleted from Title page section Reviewer 1 8. The authors note that the definition of catch up is a point of dispute in the literature, but do not explain why they selected the one that they used. The one used is a rather weak definition - children can be defined as having caught up even when falling behind in terms of CM deficits. Nonetheless, it is a commonly used definition and its use could be justified, but it does need to be justified and not used without question. Thank you. Suggested changes have been incorporated and corresponding references have been added. 7, Lines 175-178 9. -Stunting does not cause cognitive impairment, impairment and stunting are both indicators of malnutrition and possibly of lack of stimulation (and possible the combination of the two). As a result, any association between them needs to be carefully interpreted. The authors do not adequately cover this topic, which hinders the subsequent discussion of the results. Thank you. Suggested changes have been incorporated and corresponding references have been added. 19, Lines 365-372 10. If the authors are going to make the case that their results imply that nutrition programmes are needed, then a fuller discussion of the adequacy of the controls in the regression is needed. As mentioned, the association with stunting may be a result of smaller children being protected by parents leading to under stimulation - this may not be resolved by a nutrition program. Similarly, smaller children may be held back from school entry as parents do not think they are ready. The association between stunting and cognitive performance may be a result of less exposure to schooling. Thank you. Our analysis showed that apart from early childhood stunting, other factors such as poor socioeconomic status and lesser IQ of the mother, were predictors for poor cognitive performance at 9 years in children. Also, our study showed that recovery from stunting at later years in children, who were stunted at 2 years, also to be a factor for better cognitive performance at 9 years. Thus, we would summarize that cognition at 9 years is because of interplay of multiple factors during the childhood period, which is inclusive of nutrition, timing of catch up growth, socioeconomic status and caregiver’s IQ. Changes have been made in the conclusion. 20, lines – 404-406 11.Do the authors think that catch up growth could indicate a recovery from earlier malnutrition leading to a similar catch up in cognition? Or that those who catch up avoid falling further behind, while those who remain stunted continue to fall behind? Their results could support either argument, but which argument is correct has important policy implications and this should be discussed. Findings from our study support the evidence that children who catch up perform better in cognition tests at 9 years, when compared to children, who have been persistently stunted between 2 and 9 years. This has been discussed in the lines 350-371 - 11 The authors from time to time slip into causal language, this should be avoided. Thank you and this has been addressed - 12. The discussion on the importance of the first 1,000 days is a little unclear and could be improved. It is the pace and foundational nature of development in that period which is critical and this does not come through enough. Thank you and this has now been addressed. 19, lines 364-371, & 20, 391-393 13. Why report weight if you don't use it? Just for context? Yes, weight for age scores have been provided to give a complete picture of anthropometric measurements of children in the cohort. - 14. The top third based on WAMI can hardly be called high SES given the selection process. Would relatively high not be better? Thank you. We have used this nomenclature of high and low, having 33rd percentile as cut-off consistently in the previous papers published from the same cohort. Hence, we would like to retain the same nomenclature. Mohan VR, Sharma S, Ramanujam K, Babji S, Koshy B, Bondu JD, John SM, Kang G. Effects of elevated blood lead levels in preschool children in urban Vellore. Indian Pediatr. 2014 Aug;51(8):621-5. Koshy B, Srinivasan M, Zachariah SM, Karthikeyan AS, Roshan R, Bose A, Mohan VR, John S, Ramanujam K, Muliyil J, Kang G. Body iron and lead status in early childhood and its effects on development and cognition: a longitudinal study from urban Vellore. Public Health Nutr. 2020 Aug;23(11):1896-1906. - 15. When was the WAMI measure taken? What the implications of only using one time point? Did those who exhibited catch up also see an improvement in their SES which might explain the better cognitive scores? WAMI measures were available for the MAL-ED study, until 5 years of age and there were no WAMI measurements, thereafter. In the current study, WAMI scores measured at 2 years was considered, since we were interested to see, if SES status post-infancy continued to have effect on cognition scores measured at later childhood. Further, subgroup analysis showed that there is no significant improvement in SES status between the children who were stunted at 2 years and recovered at 5 years vs. those who were stunted both at 2 and 5 years. To substantiate this, we would provide following data. Of 95 children, who were stunted at 2 years, 37 (38.9%) recovered from stunting, with 58 (61.1%) of them, continued to be stunted at 5 years. 4/37 (10.8%) children who recovered from stunting had the improvement in SES from low to high by 5 years; compared to 5/58 (8.62%) who continued to be stunted at 5 years and had a similar improvement in SES status from low to high. - Reviewer 2 16. Table 4: on the PIQ, it is shown that stunting at 2 y, though with a catch-up at 5 y had 5.77 PIQ less than normal children, but the children who stunted at 2 & 5 who only caught-up at 9 had much better PIQ than normal, than children who were already catch-up since 2y and those persisted till 9 y. What could explain such a pattern? Please add discussion Thank you. We are unable to substantiate this pattern of regression co-efficients obtained between stunting with/without catch-up in early childhood and PIQ measurements at 9 years. The probable reason would be smaller sample size within the subgroups, that could have limited meaningful inference of the data. Having a smaller sample size in this study has already been highlighted as one of the limitations within the Discussion section. 20, line 394 17. . Lines 365-366 & reference 17: Did children who received intervention were during older childhood (e.g., early school-age) and hence, the damage on cognition could have occurred since early age, aside from possible short duration of intervention? Please consider. Thank you. We have added this into the Discussion. 19, Line 383-384 18. 23. Editorial errors: a. Line 116, Introduction: ‘…. (HAZ) <2 on WHO…’, should this read ‘…. (HAZ) <-2 SD…’? b. Line 351 ‘A unit increase in HAZ <2 Y…’, suggest to read, ‘A unit increase in HAZ at <2 y of age..’ Thank you. Corresponding changes made a. Page 5; line 117 b. Page 18; line 361 Thanking you Yours sincerely Authors Attachments Attachment Submitted filename: Reply to editor and reviewers final.docx https://doi.org/10.1371/journal.pone.0264010.r002
1 Dec 2021 Decision Letter - Seo Ah Hong, Editor PONE-D-21-21418R1Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohortPLOS ONE Dear Dr. Koshy, 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. Thanks for the revised manuscript. Please revise according to the reviewers' comments and return it to us. Please submit your revised manuscript by Jan 15 2022 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. 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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, Seo Ah Hong, PhD Academic Editor PLOS ONE Journal Requirements: Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. [Note: HTML markup is below. Please do not edit.] 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: (No Response) 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: Partly 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: No 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: The authors have not substantially engage with a number of key issues raised in the previous review. Most notably, they have not justified their definition of catch up growth other than to say that other people use it, so it must be okay. They do not even mention what the other definitions are and how these could explain the contradictory findings that they also seek to explain. They also do not engage with the possibility that their results are endogenous - i.e. growth and cognition both have common causes. This links to perhaps the most serious problem - the authors use causal language throughout. Growing taller will not make you smarter. Growing taller may indicate that your environment has improved and that this environment now better facilitates cognitive development. This mechanism is not explained or referenced when interpreting findings. The absence of this explanation (understanding?) may explain why the conclusions are over stated. It may also explain why the results from the literature discussed are also over interpreted as showing a causal link. Finally, the authors ignored the need to differentiate between catch up in cognition and a slowing of the rate at which children are falling behind. If children who remain stunted are falling behind at a faster rate than those who have 'caught up', then a significant result in their regression may not be indicating catch up in cognition in the latter group. This is a critical point - it speaks to the extent to which inputs in different life stages are or are not substitutable. This paper presents data from a high quality study. The analysis is sound. My concerns should be relatively easy to address, they relate only to the careful framing of the problem and results. Reviewer #2: I have no further additional comment. The authors responded to all comments, point-by-point adequately. ****** 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: No [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.0264010.r003
Revision 2
14 Dec 2021 Author Response Separate copy is uploaded To The reviewers PLOS One Re: PONE-D-21-21418 - Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort Dear reviewers, Thank you for reviewing our manuscript titled “Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort”. Author’s responses are provided below Comments Authors’ response Page number; line number 1. The authors have not substantially engage with a number of key issues raised in the previous review. Most notably, they have not justified their definition of catch up growth other than to say that other people use it, so it must be okay. They do not even mention what the other definitions are and how these could explain the contradictory findings that they also seek to explain. Thank you. Different definitions have been included in the introduction – page 6, lines 126-128. Justification for current approach is included in methodology – page 8, lines 163-166 6; 126-128 8; 163-166 2. They also do not engage with the possibility that their results are endogenous - i.e. growth and cognition both have common causes. This links to perhaps the most serious problem - the authors use causal language throughout. Growing taller will not make you smarter. Growing taller may indicate that your environment has improved and that this environment now better facilitates cognitive development. This mechanism is not explained or referenced when interpreting findings. The absence of this explanation (understanding?) may explain why the conclusions are over stated. It may also explain why the results from the literature discussed are also over interpreted as showing a causal link. Thank you. We completely agree with the lack of causalilty and have used the word ‘association’ throughout manuscript. We are happy to edit/modify if this is not clear in the manuscript. Another statement also has been added to highlight common and intersecting risks and causative pathways for both growth and cognition in early childhood. 20; 360-362 3. Finally, the authors ignored the need to differentiate between catch up in cognition and a slowing of the rate at which children are falling behind. If children who remain stunted are falling behind at a faster rate than those who have 'caught up', then a significant result in their regression may not be indicating catch up in cognition in the latter group. This is a critical point - it speaks to the extent to which inputs in different life stages are or are not substitutable. Thank you. That is a valid observation and we agree with you. We have added further information in Table 2 to show that children in all groups improved in HAZ between 2 and 9 years of age. Table 2 Thanking you Yours sincerely Authors Attachments Attachment Submitted filename: Reply to editor and reviewers.docx https://doi.org/10.1371/journal.pone.0264010.r004
23 Dec 2021 Decision Letter - Seo Ah Hong, Editor PONE-D-21-21418R2Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohortPLOS ONE Dear Dr. Koshy, 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. Thanks for the revision. You made efforts to improve the manuscript. However, some points which the reviewer #1 pointed out are so significant. So I would like you to revise once again throughout the manuscript according to the reviewer’s comments. Further, there are several miner things which the authors should correct. Table 3 showed the scores among 4 categories of stunting and catch up status of children and the coefficient of the rest three group, compared to the “never stunted group” were shown in Table 4. However, the authors used causal languages as the reviewer #1 mentioned. Thus, the uses of “reduction” or “decline” are not appropriate. You may use “lower score” instead. Please revise throughout the manuscript. Reg “Catch-up growth was associated with higher verbal intelligence as well total cognition, but not the performance component.” higher verbal intelligence as well as total cognition than what? you mean “never catch up group”? Please clarify the sentences. The authors did not discuss why the second group (catch up at 5 years) are negatively associated with performance IQ. Make some efforts on it, and reduce the length of “good follow-up rate of your cohort study” and add after the limitation of your study” to highlight the significance of your study in the discussion. Lastly, put the acronym in parentheses after the full term, if you use the term the first time. For example, IQ in the abstract, SD in the introduction and ANOVA in the method section. Please submit your revised manuscript by Feb 06 2022 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, Seo Ah Hong, PhD Academic Editor PLOS ONE Journal Requirements: Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and also include a citation and full reference for the retraction notice. [Note: HTML markup is below. Please do not edit.] 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 ******** 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: Partly ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: 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 ****** 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: No ****** 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: The authors have made some effort to engage with my comments, but some issues remain. There are still come remnants of causal language, such as 'reduction' and 'decline', but they are not serious and could easily be left. The justification of the definition use is weak, it mentions only the advantages and fails to consider the limitations (of which there are many). But as mentioned, previously, the definition is often used and so I guess its unquestioned use here is acceptable. The one remaining issue which I would like to see addressed relates to the failure to engage with the comment I made that there may be no catch up in cognition. The additions to the table to show that the z-score increased don't help and add little. The definitions of the categories already provided the outline of this information. Besides, the question was not about growth but cognition. Perhaps my explanations have not been clear, so I will try with an example. Three people enter a race (Tom, Fred and Joann). At the half way mark, Tom and Fred are 50meters behind Joann. When Joann crosses the finish line, Fred is still 50meters behind, but Tom is now 100meters behind. Can you say that Fred caught up? They all moved forward and he stopped falling behind, but he did not catch up. This is a critical point, because if that 50meters at half way is lost forever and all you can do post the half way mark is prevent someone falling further behind, interventions in the first half of the race are not substitutable. This does not mean that interventions in the second half to prevent further falling behind are not important, but there should not be any suggestion that we can wait to the second half and catch up all the way. In my mind, the possibility that there was no catch up in cognition should be mentioned. And this should be carried through to the conclusions, i.e. that the consequences of early deprivation on cognition may not be reversible, but we can act to prevent children from falling further behind. ****** 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 [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.0264010.r005
Revision 3
27 Jan 2022 Author Response To The reviewers PLOS One Re: PONE-D-21-21418 - Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort Dear editor and reviewers, Thank you for reviewing our manuscript titled “Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort”. Author’s responses are provided below Comments Authors’ response Page number; line number (Track version of the manuscript) Further, there are several miner things which the authors should correct. Table 3 showed the scores among 4 categories of stunting and catch up status of children and the coefficient of the rest three group, compared to the “never stunted group” were shown in Table 4. However, the authors used causal languages as the reviewer #1 mentioned. Thank you for the comment and the category ‘never stunted’ in table 2, 3 and 4 is replaced with ‘children who were never stunted’ Table 2, 3 and 4 Thus, the uses of “reduction” or “decline” are not appropriate. You may use “lower score” instead. Please revise throughout the manuscript. Thank you and this correction has been made in the Abstract, Results and Conclusions section. Page 4 and lines 83 and 88 Page 15 and lines 284, 287 and 291 Page 22 and lines 406 - 410 Reg “Catch-up growth was associated with higher verbal intelligence as well total cognition, but not the performance component.” higher verbal intelligence as well as total cognition than what? you mean “never catch up group”? Please clarify the sentences Thank you and this sentence has been rephrased. Page 18 and lines 318-319 The authors did not discuss why the second group (catch up at 5 years) are negatively associated with performance IQ. Thank you and this change has been made in the Discussion Page 21 and lines 392-395 Make some efforts on it, and reduce the length of “good follow-up rate of your cohort study” and add after the limitation of your study” to highlight the significance of your study in the discussion. Thank you and this change has been made in the Discussion Page 21 and lines 402-403 Lastly, put the acronym in parentheses after the full term, if you use the term the first time. For example, IQ in the abstract, SD in the introduction and ANOVA in the method section. Thank you and these suggestions have been incorporated in the Abstract, Introduction and Methods. Page 4 and line 84 Page 5 and line 103 Page 10 and lines 214-215 There are still come remnants of causal language, such as 'reduction' and 'decline', but they are not serious and could easily be left Thank you and this correction has been made throughout the manuscript. Page 4 and lines 83 and 88 Page 15 and lines 284, 287 and 291 Page 20 and line 360 The justification of the definition use is weak, it mentions only the advantages and fails to consider the limitations (of which there are many). But as mentioned, previously, the definition is often used and so I guess its unquestioned use here is acceptable. Thank you and the justification for the use of definition based on HAZ scores in this study has been provided in Methods section. Page 8 and lines 170 - 173 The one remaining issue which I would like to see addressed relates to the failure to engage with the comment I made that there may be no catch up in cognition. The additions to the table to show that the z-score increased don't help and add little. The definitions of the categories already provided the outline of this information. Besides, the question was not about growth but cognition. Perhaps my explanations have not been clear, so I will try with an example. Three people enter a race (Tom, Fred and Joann). At the half way mark, Tom and Fred are 50meters behind Joann. When Joann crosses the finish line, Fred is still 50meters behind, but Tom is now 100meters behind. Can you say that Fred caught up? They all moved forward and he stopped falling behind, but he did not catch up. This is a critical point, because if that 50meters at half way is lost forever and all you can do post the half way mark is prevent someone falling further behind, interventions in the first half of the race are not substitutable. This does not mean that interventions in the second half to prevent further falling behind are not important, but there should not be any suggestion that we can wait to the second half and catch up all the way. In my mind, the possibility that there was no catch up in cognition should be mentioned. And this should be carried through to the conclusions, i.e. that the consequences of early deprivation on cognition may not be reversible, but we can act to prevent children from falling further behind. Thank you and we agree with this suggestion and corresponding changes have been made throughout in the manuscript. Use of ‘Catch up in cognition’ in children who recovered from early life stunting has been replaced as the attainment of higher cognition scores in these children compared to persistently stunted children in relevant sections. Page 4 and lines 85-86, 89-91 Page 18 and lines 318-319 Page 21 and lines 385-389 Page 22 and line 408-410 Thanking you Yours sincerely Authors Attachments Attachment Submitted filename: Reply to editor and reviewers.docx https://doi.org/10.1371/journal.pone.0264010.r006
2 Feb 2022 Decision Letter - Seo Ah Hong, Editor Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort PONE-D-21-21418R3 Dear Dr. Koshy, 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 for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, 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, Seo Ah Hong, PhD Academic Editor PLOS ONE Additional Editor Comments (optional): Thank you for addressing all the issues reviewers raised. Copy editing is strongly recommended to improve readability before submitting the final version since some errors were found. For example, change from “height for age SD scores (HAZ) < -2 SD on WHO growth charts” to “height for age z scores (HAZ) < -2 Standard Deviation (SD) on WHO growth charts” 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 ******** 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 ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: 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 ****** 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 ****** 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: The changes made in this revision are very helpful. The causal language has been removed and the interpretation of the findings has been improved. The paper makes a useful contribution to the literature. ****** 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 https://doi.org/10.1371/journal.pone.0264010.r007
Formally Accepted
8 Feb 2022 Acceptance Letter - Seo Ah Hong, Editor PONE-D-21-21418R3 Are early childhood stunting and catch-up growth associated with school age cognition? – Evidence from an Indian birth cohort Dear Dr. Koshy: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. 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 plosone@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 Prof. Seo Ah Hong Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0264010.r008

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