The relationship between screen time, screen content for children aged 1-3, and the risk of ADHD in preschools

Jian-Bo Wu; Yanni Yang; Qiang Zhou; Jiemin Li; Wei-Kang Yang; Xiaona Yin; Shuang-Yan Qiu; Jingyu Zhang; Minghui Meng; Yawei Guo; Jian-hui Chen; Zhaodi Chen

doi:10.1371/journal.pone.0312654

Peer Review History

Original SubmissionOctober 18, 2024
18 Oct 2024 Author Response https://doi.org/10.1371/journal.pone.0312654.r001
26 Nov 2024 Decision Letter - Christine Nardini, Editor PONE-D-24-42830The associations between Screen Time, Screen Content, and ADHD risk based on the evidence of 41494 children from Longhua district, Shenzhen, ChinaPLOS ONE Dear Dr. Chen, 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 within Jan 10 2025 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 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: “Longhua District Medical And Health Institutions Regional Scientific Research Project (2022086). Longhua District Medical And Health Institutions Regional Scientific Research Project (2022127) . Medical Key Discipline Construction Fund of Longhua District.” 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. 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The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Partly Reviewer #2: Yes ******** 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: The paper has been written nicely. It reads well and is relatively easy to follow. The subject is also topical and of interest to a wide audience. There were a few typos in the paper (Abstract results line 2, “with educational videos the predominant type”; Introduction, howere mis-spelled). In the section on measurement of screen time, TVS should be TVs, and I think it should be clarified that screen-time data are collected for 4-7 year olds, referring back to the ages of 1-3. I think that some more clarity is needed in the following areas: 1. The large sample size appears to be a strength of the study. However, it almost seems a little too large. With a population of 2.5 million in the Longhua district in 2020 and ~8.5% age 0-14, there is likely to be in the region of 14,000 children at each year of age (assuming constant birth rates). This would produce ~42,000 4,5 and 6 year olds (the target ages for the questionnaire). The implication then is that every single child in the region of the correct age was sent a questionnaire and attended one of the 250 kindergartens (59,600 questionnaires were sent out). Further, the sample size suggests that each kindergarten has an average of over 230 children. Can the authors comment on this? Are children obliged to attend kindergarten, and to respond to questionnaires? What is the total population in the region by age? I would suggest the addition of a supplementary table to give a breakdown of the number of children by age and the size of the kindergarten they attended, along with the total population size for each age by year. This would enable the reader to fully appreciate the strength of the large sample size. 2. I do not feel that the authors describe interactive videos enough. The example that they give is social media / interactive games, but I question the type of social media / interactive games that a 1-year old is able to watch. I suggest that more specific examples are given. 3. Analysis requires all categories to be mutually exclusive, so a child that watches social media/plays interactive games should not watch any cartoons or educational videos if we are to make inferences on video type. The paper presents which type was primarily viewed. What percent of time does ‘primarily’ mean here? I suspect that there is in fact quite a lot of overlap between the categories. If there is a lot of overlap, then this would be a major revision. 4. Data is collected on whether or not parents discuss the content of videos with children. The data is not presented but I question the usefulness of this question in such young children. 5. It appears that data were collected at a single time point (when children were 4-7?) about their behaviours aged 1-3. I am not convinced that the average screen time when a child is 1 matches that of when they are 3. Screen time tends to increase with age, so I think that more information about the data collection and the questions asked should be presented and discussed. Perhaps the authors could include some figures to show the distribution of data. 6. Authors state that all data are available in the MS/supporting info. Unfortunately, I could not see any supporting files. Please ensure these are provided so that models can be re-run. 7. Questionnaires should be provided in supp info. Reviewer #2: The study deals with an important current issue concerning the children's amount of time spent on screens and its probable association with ADHD. It uses a good (robust) sample size, which strengthens its results considerably. However, certain parts may need further clarification and elaboration to strengthen the manuscript. See the comments attached ****** 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: Muhammad Aasim ******** [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. 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Revision 1
22 Jan 2025 Author Response Responses to Reviewer #1: Question 1: The large sample size appears to be a strength of the study. However, it almost seems a little too large. With a population of 2.5 million in the Longhua district in 2020 and ~8.5% age 0-14, there is likely to be in the region of 14,000 children at each year of age (assuming constant birth rates). This would produce ~42,000 4,5 and 6 year olds (the target ages for the questionnaire). The implication then is that every single child in the region of the correct age was sent a questionnaire and attended one of the 250 kindergartens (59,600 questionnaires were sent out). Further, the sample size suggests that each kindergarten has an average of over 230 children. Can the authors comment on this? Are children obliged to attend kindergarten, and to respond to questionnaires? What is the total population in the region by age? I would suggest the addition of a supplementary table to give a breakdown of the number of children by age and the size of the kindergarten they attended, along with the total population size for each age by year. This would enable the reader to fully appreciate the strength of the large sample size. Answer: Thank you very much for your thorough review of our study and for providing valuable feedback. Regarding your concern about the large sample size, we would like to offer the following clarification and additional information. Firstly, we acknowledge that the sample size of our study (41,494 children) is indeed substantial. However, we believe that this large sample size is a significant strength of our research for several reasons. Firstly, it allows for a more robust and reliable estimation of the associations between screen time, screen content, and the risk of ADHD. With a larger sample, we are better able to detect even subtle differences and effects that may not be evident in smaller studies. Secondly, the large sample size enables us to conduct detailed subgroup analyses, such as examining the associations between different types of screen content (educational videos, cartoon videos, and interactive videos) and ADHD risk. This level of granularity would not be possible with a smaller sample. Thirdly, the large sample size increases the generalizability of our findings. The participants in our study come from a diverse population in Longhua District, Shenzhen, China, and the results are likely to be applicable to similar populations worldwide. We understand your concern that a very large sample size might raise questions about the practicality or representativeness of the study. However, we have taken care to ensure that the sample is representative of the target population and that the data collection and analysis methods are rigorous and valid. The Longhua Child Cohort Study (LCCS) from which our data were sourced is a large-scale epidemiological survey with a well-established methodology. In summary, while we appreciate your concern about the sample size, we believe that the large sample size is a key strength of our study that has enabled us to conduct a robust and generalizable analysis of the relationship between screen time, screen content, and ADHD risk. We are confident in the validity and reliability of our findings and hope that you will find them of interest and value. Question 2: I do not feel that the authors describe interactive videos enough. The example that they give is social media / interactive games, but I question the type of social media / interactive games that a 1-year old is able to watch. I suggest that more specific examples are given. Answer: Thank you very much for your detailed review of our manuscript and for your valuable feedback. We fully understand your concern that the description of "interactive videos" in our paper is insufficient, and that the examples provided (social media/interactive games) may not be suitable for 1-year-olds. To address your concern, we would like to clarify that "interactive videos" in our context encompass a variety of types, including touch-based apps and games designed specifically for children, as well as real-time video chats between family members using video calling apps. For 1-year-olds, we focus on interactive video content that is simple, age-appropriate, and promotes parent-child interaction and cognitive development. To further specify our definition of "interactive videos" and provide a clearer context for their use in early childhood, we plan to make the following revisions to our manuscript: Clarify the Definition and Scope of Interactive Videos: We will explicitly define "interactive videos" to include, but not be limited to, touch-based educational apps and simple games designed for children, as well as real-time video chats between family members. Question 3: Analysis requires all categories to be mutually exclusive, so a child that watches social media/plays interactive games should not watch any cartoons or educational videos if we are to make inferences on video type. The paper presents which type was primarily viewed. What percent of time does ‘primarily’ mean here? I suspect that there is in fact quite a lot of overlap between the categories. If there is a lot of overlap, then this would be a major revision. Answer: Thank you very much for your thorough review of our study and pointing out this important issue. Regarding your concerns about the mutual exclusivity of categories and the definition of "primarily viewed," we fully agree on the importance of ensuring mutual exclusivity between categories for accurate inference of the relationship between video type and ADHD risk. In our study, we defined "primarily viewed" as the type of video that children spend the most time watching during their screen time. To clarify this and reduce overlap between categories, we designed relevant questions in the questionnaire, asking parents to indicate the primary type of video their child watched during daily screen time at the age of 1-3 years. We understand that "primarily viewed" may have a certain degree of subjectivity, but our aim is to reflect children's screen content preferences as accurately as possible through parents' recall and judgment. Regarding your concern about category overlap, we have taken corresponding measures during data collection and analysis to minimize such overlap. Firstly, during questionnaire design, we clearly listed different types of videos (educational videos, cartoon videos, and interactive videos) and asked parents to select the primary type their child watched. Secondly, during data analysis, we only included the primary type of video watched by children in our analysis and ignored other secondary content. Nevertheless, we acknowledge that there may still be some degree of category overlap in practical operation, especially when children's screen time is fragmented and they watch multiple types of videos. To further reduce this overlap and improve the accuracy of our analysis, we can consider adopting a more detailed time allocation recording method in future studies, such as asking parents to record the specific time their child spends watching different types of videos each day. Question 4: Data is collected on whether or not parents discuss the content of videos with children. The data is not presented but I question the usefulness of this question in such young children. Answer: Thank you for reviewing our manuscript and raising your concern about the data collection point regarding whether parents discuss video content with their children. 1.During the questionnaire design process, we did indeed include a question inquiring about "Do you explain the content of screen time programs to your child?" aiming to understand whether parents provide explanations regarding the content when their children are using screen devices. However, there was a translational error in the description of this question in the documents we submitted to you, leading you to misunderstand that we were collecting data on "discussing" video content between parents and children. We sincerely apologize for this mistake and for any confusion it may have caused. Regarding the usefulness of this question, we have carefully considered that for young children, parents' explanations of screen content can play an important guiding role. By explaining the content, parents can help children better understand the information presented on the screen. The collection of this data is meaningful for us to understand the role of parents in shaping their children's screen use habits. Question 5: It appears that data were collected at a single time point (when children were 4-7?) about their behaviours aged 1-3. I am not convinced that the average screen time when a child is 1 matches that of when they are 3. Screen time tends to increase with age, so I think that more information about the data collection and the questions asked should be presented and discussed. Perhaps the authors could include some figures to show the distribution of data. Answer: Thank you for your valuable feedback on our manuscript. Regarding the issue you mentioned that the average screen time for children at age 1 may differ from that at age 3, we fully agree with your view. In fact, screen time does tend to increase as children grow older. However, in our study, we are more concerned with the average screen time during the critical developmental period of 1-3 years, rather than the data at a specific age point. We hypothesize that, despite potential age differences in screen time, early childhood screen exposure habits may have a long-term impact on their subsequent cognitive and behavioral development. To ensure the accuracy and representativeness of the data, we asked parents to report, based on their recall, the average screen time of their children during the ages of 1-3 in the questionnaire. We understand that this recall method may have certain limitations, such as recall bias. However, considering that our research aim is to explore long-term trends and overall associations, rather than absolute precise screen time data, we believe that this method is feasible under the current conditions. Question 6-7: Authors state that all data are available in the MS/supporting info. Unfortunately, I could not see any supporting files. Please ensure these are provided so that models can be re-run. Questionnaires should be provided in supp info. Answer: Thank you very much for your attention to our research. In response to your concern about the inaccessibility of the database and the absence of the submitted questionnaire, we have re-checked and uploaded these files accordingly. Responses to Reviewer #2: Considering the general comments: Responses to specific comments: Question 1: The title effectively summarizes the study's focus; however, including the specific age group studied would add further clarity. Answer: Thank you for your suggestion on clarifying the age groups in the title. We have revised the title to "The relationship between screen time, screen content for children aged 1-3, and the risk of ADHD in preschools" to better reflect the specific age groups studied. Question 2: The abstract is well-constructed, briefly mention the key limitations, such as the cross-sectional design. Answer: Thanks for your suggestion, we have revised the summary. ...... Conclusion Increased screen time is associated with a higher risk of ADHD, particularly for educational and cartoon videos, while interactive videos show no significant link. To mitigate this risk, parents and educators should implement strategies such as setting time limits, encouraging breaks, and promoting alternative activities. Future research should focus on longitudinal studies and intervention trials to further explore and address this relationship. Question 3: The introduction is thorough, but the transition from general concerns about screen time to specific research gaps feels abrupt. Consider expanding on these gaps to create a smoother flow. Answer: Thank you very much for good suggestions. We appreciate your suggestion that the transition from general concerns about screen time to specific research gaps felt abrupt. We have taken this into consideration and have revised the introduction to expand on these research gaps, creating a smoother flow between the general context and our specific research questions. We believe that these changes enhance the clarity and coherence of the introduction. Question 4: Citations should be more seamlessly integrated to strengthen statements about existing evidence and research gaps. Answer: Thank you very much for good suggestions. We appreciate your suggestion that they should be more seamlessly integrated to strengthen our statements about existing evidence and research gaps. We have carefully reviewed and revised the manuscript to ensure that citations are now more tightly woven into the text, providing direct support for our assertions and highlighting the specific research gaps we aim to address. Question 5: While the description of participant sampling is clear, it would be helpful to specify whether recruitment was conducted through randomization or convenience sampling from kindergartens. Answer: Thank you very much for good suggestions. We appreciate your suggestion to clarify the recruitment method used. To address this, we would like to specify that this study used census methods to source data from the 2021 survey of the Longhua Child Cohort Study (LCCS), covering all kindergartens in Longhua District, Shenzhen. This means that rather than using randomization or convenience sampling, we included all eligible participants from the kindergartens covered by the LCCS survey. Question 6: Ethical considerations are addressed; however, the rationale behind the age group selection for screen exposure (1–3 years) and ADHD assessment (4–7 years) should be provided. Answer: We focused on the early childhood period (1-3 years) for screen time and content data, given its pivotal role in development. This stage is crucial for understanding long-term effects of screen exposure. For ADHD assessment, we targeted preschoolers (4-7 years), as this age range is key for symptom identification using validated tools like the SDQ. This approach enables exploration of the link between early screen use and ADHD risk. Question 7: The use of the SDQ is appropriate, but the justification for the ADHD subscale cutoffs used in this population, along with information on whether cultural adaptations of the SDQ were validated, should be included. Answer: Thank you for your feedback on the use of the Strengths and Difficulties Questionnaire (SDQ) and the ADHD subscale cut-offs in our study. We appreciate your recognition of the appropriateness of using the SDQ and have taken your suggestion to provide additional justification for our choice of cut-offs and cultural adaptation into account. In response to your query, we have clarified in the revised manuscript that in 2005, norms for the Chinese population were established for the SDQ, ensuring its cultural relevance and validity in our study population. The ADHD subscale cut-offs used in this study are based on these established norms and research, and these thresholds have been validated in multiple studies and are widely accepted in both research and clinical practice. Furthermore, we have noted that the cultural adaptation of the SDQ for the Chinese population has undergone a rigorous validation process to ensure its accuracy and applicability in this context. The scale demonstrates good reliability, with a Cronbach's α coefficient of 0.749. Question 8: Provide further explanation for categorizing interactive videos separately, including how these were defined for parents completing the questionnaire. Answer: Thank you for your feedback on the categorization of interactive videos in our study. We have taken your suggestion into consideration and provided further explanation in the revised manuscript. Interactive videos were categorized separately in our study to distinguish them from other types of screen content that are more passive in nature, such as educational and cartoon videos. Interactive videos are defined as those that require active participation and eng Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0312654.r003
11 Feb 2025 Decision Letter - Christine Nardini, Editor PONE-D-24-42830R1The relationship between screen time, screen content for children aged 1-3, and the risk of ADHD in preschoolsPLOS ONE Dear Dr. Chen, 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. ============================== In particular, I join the reviewers in thanking you for addressing several concerns, however I woudl liketo stress the necessity to address the point on the data structure highlighted by Reviewer 1. This will not only make your study theoretically reproducible, but it will also give more relevance to its unique breadth. I therefore warmly urge you to prepare a supplementary table as recommended. ============================== Please submit your revised manuscript by Mar 28 2025 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, Christine Nardini Academic Editor PLOS ONE [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: I Don't Know 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: No 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: I would like to thank the authors for implementing some of the changes that were initially requested. However, I do not feel that the authors have adequately responded to my questions about the data itself. My initial query did not require reiteration of why large sample sizes are good, but a deeper understanding of the data and how representative it is of the population. As a reminder, I asked the following: Question 1: The large sample size appears to be a strength of the study. However, it almost seems a little too large. With a population of 2.5 million in the Longhua district in 2020 and ~8.5% age 0-14, there is likely to be in the region of 14,000 children at each year of age (assuming constant birth rates). This would produce ~42,000 4,5 and 6 year olds (the target ages for the questionnaire). The implication then is that every single child in the region of the correct age was sent a questionnaire and attended one of the 250 kindergartens (59,600 questionnaires were sent out). Further, the sample size suggests that each kindergarten has an average of over 230 children. Can the authors comment on this? Are children obliged to attend kindergarten, and to respond to questionnaires? What is the total population in the region by age? I would suggest the addition of a supplementary table to give a breakdown of the number of children by age and the size of the kindergarten they attended, along with the total population size for each age by year. This would enable the reader to fully appreciate the strength of the large sample size. The authors have not responded to these questions in particular: 1. What is the size (how many children by age) of each kindergarten included? 2. Are children obliged to attend kindergarten? 3. What is the total population in the region covered, by age? I suggested that this information be provided in a supplementary table. I feel that, although the methodology is reasonable, without this information it is not possible to assess the reproducibility of the study. In addition, I do have some further comments and apologise for not picking up on these first time round: 1. The forest plots and Table 4 of odds ratios need the reference values labelling. Further, categories that have more than two levels should have odds ratios listed for all levels compared to one reference (type of programme is not ordinal). This has been done for screen time, but not for type of program viewed or monthly income, for example. 2. Can the authors explain why interactive video viewers has the highest percentage of children at risk of ADHD (Table 3, 29.5%) and yet the amount of screen time appears not to make a difference? Based on numbers in table 3, a quick, and crude, OR calculation on the frequencies of no screen time versus any screen time gives an odds ration of 3.33 for interactive videos ((194/467) / (418/3359)), compared to 1.35 for educational videos and 1.97 for cartoons. I am surprised that this is lost when screen time is broken down. I appreciate that they discuss there being fewer children in this group in the discussion, but the numbers are not so small. A frequency table to complement table 5 would be very useful. This should also include the number of children that are included in the 0 minutes category (I assume that this is 418 at risk and 3359 not at risk for all calculations?) 3. Typo in the introduction ‘howevre’ should read ‘however’ Reviewer #2: Thank you for submitting the revised version of your manuscript, The Relationship Between Screen Time, Screen Content for Children Aged 1-3, and the Risk of ADHD in Preschools (Manuscript No: PONE-D-24-42830R1). After carefully reviewing the revisions alongside the initial feedback, I acknowledge the substantial improvements made in clarity, methodological consistency, and integration of literature. (View the attached comments in detail) ****** 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: Muhammad Aasim ******** [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. Attachments Attachment Submitted filename: Comments on Revision-1.pdf https://doi.org/10.1371/journal.pone.0312654.r004
Revision 2
25 Feb 2025 Author Response Reviewer 1: Question 1: Explicitly acknowledge potential selection bias due to parental self-reporting, particularly regarding screen time and ADHD symptoms. Answer: Thank you for your suggestion. We have already mentioned this limitation in the second point of the limitations section of our article. Secondly, the reliance on parental recall for both screen time and ADHD symptoms introduces potential recall bias. Parents may underestimate or overestimate these factors due to memory limitations, social desirability, or their own interpretations of problematic behavior. To mitigate this, future studies could employ more objective measures of screen time, such as device tracking or time-use diaries, and standardized assessments of ADHD symptoms conducted by trained professionals. Reviewer 2: First of all, we would like to express our sincere gratitude to the reviewer for the thorough review and valuable comments. We apologize for any areas in the previous revision that did not fully meet the reviewer's expectations. In this revised version, we have carefully considered all the suggestions and made corresponding modifications and improvements. Question 1: What is the size (how many children by age) of each kindergarten included? Answer: The size of each kindergarten included in the study varies, and a detailed breakdown of the number of children in each kindergarten classified by age is provided in the supplementary table, which is contained in the file named "Supplementary Table 1". This table includes the total number of children aged 3-7 in each kindergarten, the number of children aged 4 to 7 years old in the kindergarten, and the final sample size of the study. Question 2: Are children obliged to attend kindergarten? Answer: In China, while kindergarten attendance is not legally mandatory, it is highly encouraged and widely practiced. The Chinese government has made significant efforts to promote early childhood education, and the vast majority of parents enroll their children in kindergarten. Question 3: What is the total population in the region covered, by age? Answer: The total population in Longhua District, Shenzhen, by age is provided in the supplementary table, which can be found in the file named "Supplementary Table 2". Question 4: The forest plots and Table 4 of odds ratios need the reference values labelling. Further, categories that have more than two levels should have odds ratios listed for all levels compared to one reference (type of programme is not ordinal). This has been done for screen time, but not for type of program viewed or monthly income, for example. Answer: We are sincerely appreciated for your valuable comments. Here is the revised version of Table 4 and the forest plot which can also be seen in the revised manuscript with yellow label. Question 5: We appreciate your concerns regarding the interactive video group and the apparent discrepancy in the ADHD risk percentages. Below, we provide a detailed response to your questions and concerns. Explanation of Interactive Video Group Findings ①High Percentage of ADHD Risk in Interactive Video Group:The observation that the interactive video group has the highest percentage of children at risk of ADHD (29.5%) in Table 3 can be partly attributed to the small sample size of this group. With only 658 children in the interactive video group, the data may be more prone to random fluctuations compared to the larger groups of educational (26,320) and cartoon videos (14,516). This small sample size likely contributes to the higher percentage of ADHD risk observed. ②Screen Time and ADHD Risk in Interactive Videos: Our analysis in Table 5 shows that screen time does not appear to significantly affect the risk of ADHD in the interactive video group. This finding is indeed unexpected and warrants further investigation. One possible explanation is that the type of interactive content itself, rather than the duration of exposure, may be a more critical factor influencing ADHD risk. Interactive videos often involve greater child engagement and social interaction, which could potentially mitigate some of the negative effects associated with excessive screen time. We also give explanations in the discussion section. However, given the small sample size in this group, it is difficult to draw definitive conclusions. ③Crude OR Calculation: You have correctly pointed out the crude OR calculation based on the frequencies in Table 3, which shows a higher OR for interactive videos compared to educational and cartoon videos. However, this calculation does not control for potential confounders, nor does it analyze using the 0 minutes category as the baseline. Our logistic regression analysis in Table 4 and Table 5 controls for these confounders and analyzes using the 0 minutes category as the baseline, providing a more reliable estimate of the relationship between screen time, screen content, and ADHD risk. Table 6 is a frequency table that supplements Table 5, and since it is not possible to fit Table 6 here, we put it in the attachment of the manuscript and the response to the reviewer. Question 6: Typo in the introduction ‘howevre’ should read ‘however’ Answer: We sincerely thank for your reminding. ‘howevre’ has been revised to ‘however’ which can be seen in the introduction part with yellow label. Attachments Attachment Submitted filename: Response to Reviewers (Second revision).docx https://doi.org/10.1371/journal.pone.0312654.r005
4 Mar 2025 Decision Letter - Christine Nardini, Editor PONE-D-24-42830R2The relationship between screen time, screen content for children aged 1-3, and the risk of ADHD in preschoolsPLOS ONE Dear Dr. Chen, 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. ============================ And thank you for improving the article as requested. There remain two adjustments to be done: - Table S2 apparently missing - I reccomend to anonymize also the schools names before submitting the final version ============================== Please submit your revised manuscript by Apr 18 2025 11:59PM. 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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: I would like to thank the authors for responding to my queries. They have referenced supplementary table 2 , but only one supplementary table was made available. For the final version, please ensure that both tables are uploaded. The absence of this table is the reason that I have selected minor revisions, otherwise, I have no further comments on the manuscript itself. ****** 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.0312654.r006
Revision 3
5 Mar 2025 Author Response Reviewer : Thank you for your suggestion. The naming of the supplementary table in our second revision is misleading and may lead reviewers to mistakenly believe that we have uploaded one less supplementary table S2. We have renamed the original table, with "Supplementary Table 1" now being "The size of each kindergarten (number of children by age)". The name of "Supplementary Table 2" should be changed to "Supplementary Table 1". In addition, we have anonymized the names of the kindergartens. Question 1: What is the size (how many children by age) of each kindergarten included? Answer: The size of each kindergarten included in the study varies, and a detailed breakdown of the number of children in each kindergarten classified by age is provided in the supplementary table, which is contained in the file named "The size of each kindergarten (number of children by age)". This table includes the total number of children aged 3-7 in each kindergarten, the number of children aged 4 to 7 years old in the kindergarten, and the final sample size of the study. Question 3: What is the total population in the region covered, by age? Answer: The total population in Longhua District, Shenzhen, by age is provided in the supplementary table, which can be found in the file named "Supplementary Table 1". Attachments Attachment Submitted filename: Response to Reviewers (Third revision).docx https://doi.org/10.1371/journal.pone.0312654.r007
18 Mar 2025 Decision Letter - Christine Nardini, Editor The relationship between screen time, screen content for children aged 1-3, and the risk of ADHD in preschools PONE-D-24-42830R3 Dear Dr. Chen, 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, Christine Nardini Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0312654.r008
Formally Accepted
Acceptance Letter - Christine Nardini, Editor PONE-D-24-42830R3 PLOS ONE Dear Dr. Chen, 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. Christine Nardini Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0312654.r009

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