Mid-life social participation in people with intellectual disability: The 1958 British birth cohort study

Zuyu Wang; Andrew Sommerlad; Angela Hassiotis; Marcus Richards; Gill Livingston

doi:10.1371/journal.pone.0302411

Peer Review History

Original SubmissionNovember 6, 2023
28 Feb 2024 Decision Letter - Robert Didden, Editor PONE-D-23-29741Mid-life social participation in people with intellectual disability: the 1958 British birth cohort studyPLOS ONE Dear Dr. Wang, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please submit your revised manuscript by Apr 13 2024 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. 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The paper is of interest but may benefit from a revision. The comments are straightforward and largely related to issues of clarification. Also pay attention to the reviewer's comment regarding clinical implications of this study. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Partly ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: I Don't Know ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? 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Reviewer #1: 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 article “Mid-life social participation in people with intellectual disability: the 1958 British birth cohort study ”is based on the 1958-birth cohort in England, Scotland and Wales, followed-up at ages 44 and 50 years. The study targets different aspects of social participation, and QoL and compares cognitive subgroups; those with mild intellectual disability, borderline intellectual functioning and those with IQs above 85. The article is well written and mostly clear. Abstract: I wonder about this sentence: “Having a confiding relationship partially mediated the association at age 50 between IQ and cognition (6.4%) and QoL (27.4%) for people with borderline intellectual functioning”. Is the result one of the main findings? Background: Page 4, regarding study aims: “2) Does social participation (social contacts and confiding relationships) mediate the association between intelligence quotient scores (IQ) in childhood and future cognition and QoL in people with and without intellectual disability?” My question is if it could also be the opposite, i.e., that IQ in childhood mediates later social participation? Demographic information: It would be valuable if the authors explained RG I, II, III IQ in childhood: I wonder about the test methods at age 11 years, were there test data from some established tests, such as the WISC? Perhaps this is explained in reference no 15. Were tests performed by psychologists? The mild intellectual disability range is broad, IQ appr. 50- appr.70. Was that considered? The three different parts dealing with Social participation: My question is if the participants with mild intellectual disability answered these forms entirely by themselves or if they received some help, perhaps explaining a question? Measurement of cognitive ability in midlife: I have a similar question here about the test data, was there any correlation with the WAIS test? Who carried out the test procedure? Psychologists? Do the authors know if most of those who participated had results in the IQ “higher” IQ range 60-70? Health status: It is very valuable that also mental health status is included. However, I have the same question here as previously, did the participants with mild intellectual disability receive any help to understand the questions. Results: Social network: First line, I think it is important to specify that it is mild intellectual disability Mediation analysis: "Social participation mediation of the relationships between IQ in childhood and cognition, and QoL at age 50": To me, this part is not so easy to understand. However, the Tables in the Appendix are explanatory. My question: When the authors mention cognition in the adults, does it include an IQ measure? Were IQ levels within the same areas in adulthood as at age 11? Discussion: The closest person: Please check if intellectual disability is the correct term, or if it should be mild intellectual disability. Perhaps it would be more relevant if the group consisted of those with mild intellectual disability. “A study reported that most people with intellectual disability are not in intimate relationships; 99% of older people with intellectual disability are single(28).” I think the authors should add if the percentage 99% refers to all levels of intellectual disability. The sentence:” Only 5.6% of people with mild intellectual disability and 6.9% of people with borderline intellectual functioning reported their closest persons were friends, compared to 8.6% of people with IQ above 85”. To me the percentages seem very similar, maybe that should be commented on. Findings for midlife cognition: The sentences: “This birth cohort also allowed us to test the hypothesis that social participation mediated the association between IQ and cognition.” My question is if it is not exactly the opposite, i.e., that that IQ and cognition were of importance for social participation. The following part seems for me a bit too detailed, is it important information? “We found that confiding relationships were potentially important for the future cognition of people with borderline intellectual functioning, because they mediated 6.4% of the effect of IQ in childhood on cognition at age 50, compared to the smaller (0.5%) mediating effect for people with IQ above 85, although we were unable to test this in people with mild intellectual disability due to the small sample size.” Findings about QoL: To me it is difficult to understand the relevance of the following sentence: “An implication is that if adults with borderline intellectual functioning had confiding relationships with more than one person, someone else who was not necessarily the closest person but outside their families might be able to act as a confidant to extend the size of their social networks and thus confer protection from cognition decline.” Finally, I think the authors should give more clinical implications of their study. How will the study populations and professionals benefit from this study and its results? ****** 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 ******** [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.0302411.r001
Revision 1
25 Mar 2024 Author Response Mid-life social participation in people with intellectual disability: the 1958 British birth cohort study Thank you for the comments from editors and reviewers. We have addressed these point by point below with our response in blue and revised sections of the manuscript in italics. Reviewer #1. 1. Reviewer #1: The article “Mid-life social participation in people with intellectual disability: the 1958 British birth cohort study” is based on the 1958-birth cohort in England, Scotland and Wales, followed-up at ages 44 and 50 years. The study targets different aspects of social participation, and QoL and compares cognitive subgroups; those with mild intellectual disability, borderline intellectual functioning and those with IQs above 85. The article is well written and mostly clear. Response: Thank you very much. 2. Abstract: I wonder about this sentence: “Having a confiding relationship partially mediated the association at age 50 between IQ and cognition (6.4%) and QoL (27.4%) for people with borderline intellectual functioning”. Is the result one of the main findings? Response: Yes, it is one of the main findings, and helps to answer our research question (2). 3. Background: Page 4, regarding study aims: “2) Does social participation (social contacts and confiding relationships) mediate the association between intelligence quotient scores (IQ) in childhood and future cognition and QoL in people with and without intellectual disability?” My question is if it could also be the opposite, i.e., that IQ in childhood mediates later social participation? Response: We agree with the reviewer, IQ is associated with later social participation, and that is the first research question in this study, and we show the analysis in the results. In the second research question, we investigated how midlife social participation has impact on the relationship between IQ in childhood and cognition in later life. 4. Demographic information: It would be valuable if the authors explained RG I, II, III Response: Thank you for pointing this out. We have rewritten the sentence as ‘social class was defined as the employment of the mother’s partner at birth using The Registrar-General’s Social Class Scheme: The Stevenson Version. (RG I, II, III non-manual, III manual, IV, V); ’ , and added a reference: Carr-Hill RA, Pritchard CW, Carr-Hill RA, Pritchard CW. The registrar-general’s social class scheme: The Stevenson version. Women’s Social Standing: The Empirical Problem of Female Social Class. 1992;10–24. 5. IQ in childhood: I wonder about the test methods at age 11 years, were there test data from some established tests, such as the WISC? Perhaps this is explained in reference no 15. Were tests performed by psychologists? Response: Yes, it is explained in the reference no.16 (was no.15). As specified in the methods, at age 11 the tests used to calculate IQ covered (1) general ability, (2) reading comprehension, (3) mathematical tests and (4) copying design. Tests 1,2 and 4 were prepared by the National Foundation for Educational Research in England and Wales. The tests were administered by teachers. The mild intellectual disability range is broad, IQ appr. 50- appr.70. Was that considered? Responses: Yes, we are using the definition of mild intellectual disability according to ICD-10: 2019, F70 Mild mental retardation: approximate IQ range of 50 to 69 (in adults, mental age from 9 to under 12 years). 6. The three different parts dealing with Social participation: My question is if the participants with mild intellectual disability answered these forms entirely by themselves or if they received some help, perhaps explaining a question? Response: There was an interviewer or nurse present who could help if needed. At age 44, the questions about social participation are included in the self-completion booklet. Participants were asked to complete it themselves before a nurse came to see them, then they gave it to the nurse during the visit. Participants were able to ask the nurse for help with the questionnaire. At age 50, the questionnaire was not included in the self-completion questionnaire but was read out by the interviewer using a show card presented by the interviewer. Thus participants could ask help from the interviewer immediately if they could not understand the question. 7. Measurement of cognitive ability in midlife: I have a similar question here about the test data, was there any correlation with the WAIS test? Who carried out the test procedure? Psychologists? Response: The tests were administered by trained interviewers working on these surveys. The WAIS was not administered. All tests were read out or performed by trained interviewers, working on surveys including the English Longitudinal Study of Ageing (ELSA) (http://www.ifs.org.uk/elsa/) 8. Do the authors know if most of those who participated had results in the IQ “higher” IQ range 60-70? Response: Yes, we know the distribution of IQ scores. Please see the graph below, the x axis is the IQ scores of participants with mild intellectual disability in this study and more of them had IQ of 60 to 70. 9. Health status: It is very valuable that also mental health status is included. However, I have the same question here as previously, did the participants with mild intellectual disability receive any help to understand the questions. Response: The CIS-R questionnaires was computer administered and self-completed, with the support of trained nurses. Health questions were included in the self-completion booklet, and participants were asked to complete and return this with their biomedical samples. If participants had any questions or needed any help, they could ask from nurses or research team. 10. Results: Social network: First line, I think it is important to specify that it is mild intellectual disability Response: Thank you for pointing this out. We have added the word “mild” 11. Mediation analysis: "Social participation mediation of the relationships between IQ in childhood and cognition, and QoL at age 50": To me, this part is not so easy to understand. However, the Tables in the Appendix are explanatory. Response: Thank you for your comment and saying it was explained. and we have ensured that it is clear. 12. My question: When the authors mention cognition in the adults, does it include an IQ measure? Were IQ levels within the same areas in adulthood as at age 11? Response: As specified in the methods, at age 11 the tests used to calculate IQ covered general ability, reading comprehension, mathematical tests and copying. The measures in adulthood tested memory, verbal fluency and speed of processing. These latter tests are common cognitive tests used in adulthood but are not intended to provide an IQ measure. 13. Discussion: The closest person: Please check if intellectual disability is the correct term, or if it should be mild intellectual disability. Perhaps it would be more relevant if the group consisted of those with mild intellectual disability. “A study reported that most people with intellectual disability are not in intimate relationships; 99% of older people with intellectual disability are single(28).” I think the authors should add if the percentage 99% refers to all levels of intellectual disability. Response: It is about all levels of intellectual disability, and we have added ‘all severity’ in the sentence. As it covers mild intellectual disability, and the finding is that nearly everyone is single we think it is relevant. 14. The sentence:” Only 5.6% of people with mild intellectual disability and 6.9% of people with borderline intellectual functioning reported their closest persons were friends, compared to 8.6% of people with IQ above 85”. To me the percentages seem very similar, maybe that should be commented on. Response: Thank you. We have added “Most people regardless of their IQ reported that their closest person was a relative” Findings for midlife cognition: 15. The sentences: “This birth cohort also allowed us to test the hypothesis that social participation mediated the association between IQ and cognition.” My question is if it is not exactly the opposite, i.e., that that IQ and cognition were of importance for social participation. Response: We discussed this above- see answer to question 3. 16. The following part seems for me a bit too detailed, is it important information? “We found that confiding relationships were potentially important for the future cognition of people with borderline intellectual functioning, because they mediated 6.4% of the effect of IQ in childhood on cognition at age 50, compared to the smaller (0.5%) mediating effect for people with IQ above 85, although we were unable to test this in people with mild intellectual disability due to the small sample size.” Response: Thank you for your comment. We think it is important and suggests that people with ID show effects of isolation on cognition at an earlier age than people with higher IQ. 17. Findings about QoL: To me it is difficult to understand the relevance of the following sentence: “An implication is that if adults with borderline intellectual functioning had confiding relationships with more than one person, someone else who was not necessarily the closest person but outside their families might be able to act as a confidant to extend the size of their social networks and thus confer protection from cognition decline.” Response: We are sorry this was not clear and have rewritten this to say “ The implication is that if adults with borderline intellectual functioning had confiding relationships with more than one person, someone else who was not necessarily the closest person but outside their families might be able to act as a confidant and this would extend their social participation and thus might confer protection from cognition decline.” 18. Finally, I think the authors should give more clinical implications of their study. How will the study populations and professionals benefit from this study and its results? Response: Thank you for your comments, we agree with the reviewer. We have added “ This informs future clinical research into interventions for people with intellectual disability as it provides evidence that social participation may be particularly important to protect cognition in this vulnerable group.” Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0302411.r002
3 Apr 2024 Decision Letter - Robert Didden, Editor Mid-life social participation in people with intellectual disability: the 1958 British birth cohort study PONE-D-23-29741R1 Dear Dr. Wang, 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. 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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: I Don't Know ****** 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: Thank you very much for your clear answers to my questions! I would just like to suggest that it could be mentioned that it was teachers who carried out the cognitive tests in chikdhood. Perhaps it could also be mentioned if the teachers had any collaboration with a psychologist with regard to interpretation of test results. ****** 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.0302411.r003
Formally Accepted
7 May 2024 Acceptance Letter - Robert Didden, Editor PONE-D-23-29741R1 PLOS ONE Dear Dr. Wang, 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 Professor Robert Didden Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0302411.r004

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