PONE-D-20-30886

Changes in toothbrushing frequency and its associated factors from 2006 to 2014 among French adolescents

PLOS ONE

Dear Dr. Fernandez de Grado,

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 Jan 30 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.

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: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Frédéric Denis, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1.) Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2.) Please provide additional details regarding participant consent. In the ethics statement in the Methods and online submission information, please ensure that you have specified what type you obtained (for instance, written or verbal, and if verbal, how it was documented and witnessed). If your study included minors, state whether you obtained consent from parents or guardians. If the need for consent was waived by the ethics committee, please include this information.

3.) We note that you have indicated that data from this study are available upon request. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions.

In your revised cover letter, please address the following prompts:

a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially identifying or sensitive patient information) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent.

b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings as either Supporting Information files or to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. Please see http://www.bmj.com/content/340/bmj.c181.long for guidelines on how to de-identify and prepare clinical data for publication. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories.

We will update your Data Availability statement on your behalf to reflect the information you provide.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: I Don't Know

Reviewer #2: No

Reviewer #3: N/A

**********

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

Reviewer #3: 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: No

Reviewer #2: Yes

Reviewer #3: 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: Thank you very much for submitting your research to Plos One. The reviewer would like to make several comments on your article.

1.What is the main message the authors would like to deliver?

2.Pleaes comment on the accuracy of the self-reported questionnaire.

3.Please provide the full paragraph of self-reported questionnaires.

4.Please comment on this.

This cutoff was chosen to match the international recommendations for tooth brushing and to avoid groups of subjects being too small.

5.Please comment on confounding factor.

6.Can you provide the data for more recent years.

7.Can the individual be followed up.

8.What is the rationale for toothbrushing frequency?

9.Please provide the possible explanation.

10. Please provide the clinical relevance.

Thank you very much.

Reviewer #2: The paper shows that among French adolescents, toothbrushing frequency changed from 2006 to 2014 using the data of Health Behavior in School-aged Children (HBSC) survey.

This is an interesting study. However, I would like to make some points regarding the manuscript. The article needs to be revised. First, the authors should follow the STROBE guideline if this study is an observational study. Second, the logic is unclear. The authors answered to a reviewer in the last revision as below.

However, the current form is not appropriate.

1. I actually wasn’t entirely sure what the research question was. I believe the question was to determine whether the percentage adolescents who brushed their teeth twice a day changed over time. What was confusing was that the predictors were all individual/family level variables. So there seemed to be a mismatch between the question and the factors examined. To determine predictors of change over time, I would look to broader social factors. The authors seemed to recognize this, because in their discussion, they speculated about the role of a social program on the outcome. In their study, however, they did not examine the effect of this social program analytically. Thus, there is a mismatch between the research question and the predictors included in the study. To me, this is a fatal flaw of the paper.

Answer: It seems our secondary objective was misunderstood by this reviewer which led to many criticisms. We wanted to determine if the relationship between toothbrushing frequency and its predictors changed over time among French adolescents. We did NOT aim to determine predictors of changes in toothbrushing frequency; a goal that would require a longitudinal study. We did NOT aim to offer an analytical model. We reformulated our objectives : “The objectives of the present study were (1) to provide an update on the evolution of the tooth brushing frequency among French adolescents, and (2) to determine if the relationship between toothbrushing frequency and its socio-economic and behavioral predictors changed over the years, using the data from the successive French HBSC studies of 2006, 2010 and 2014.”

2. The authors seemed to have ideas about the importance of different classes of predictors, but they failed to describe any theoretical underpinning for their ideas. I believe we have passed the time when atheoretical research is acceptable. At this time, the best way for research to make a contribution is if it is theory-driven. The authors should ground their work in theory. Doing so would help the authors address the point above. This is a flaw that is addressable, but addressing it would turn this into a new paper.

Answer: We indeed have theory about the roles of the identified predictors, which are discussed in the paper. We rewrote the discussion to make it clearer. However, we insist on the fact that this article’s main goal was to identify changes in adolescent toothbrushing, and is thus a descriptive article whose goal is to offer information about the situation, not to offer a full theory on the relationships between toothbrushing and all its associated factors.

3. The analytic strategy is weak. There are serious drawbacks to using stepwise regression, one being that results using this approach are not generalizable. The results are contingent on the specific sample on which the analysis is run. See: https://www.stata.com/support/faqs/statistics/stepwiseregression-problems/ This is a flaw that is addressable, but addressing it would turn this into a new paper. My advice would be to start with theory and figure out the ways in which their study can help inform our understanding of that theory.

Answer: We rewrote the article, deleted the part about stepwise regression and choose to present only descriptive models to make it clearer that this is a descriptive article. We never aimed to offer more than a description of toothbrushing frequency and its associated factors among French adolescents. Our discussion mentions the possible consequences and origin of these associations, but we did not aim to offer a full theory about the mechanisms leading to these associations.

Furthermore, to be accepted for publication in PLOS ONE, research articles must satisfy the following criteria:

1. The study presents the results of original research.

2. Results reported have not been published elsewhere.

3. Experiments, statistics, and other analyses are performed to a high technical standard and are described in sufficient detail.

4. Conclusions are presented in an appropriate fashion and are supported by the data.

5. The article is presented in an intelligible fashion and is written in standard English.

6. The research meets all applicable standards for the ethics of experimentation and research integrity.

7. The article adheres to appropriate reporting guidelines and community standards for data availability.

The current form is not acceptable in this journal policy.

TITLE

1) Please add the study design following the STROBE guideline if it is a cross-sectional study.

INTRODUCTION

1) The logic is unclear. If this is a descriptive epidemiology, the authors should need hypothesis formulation. The structure of this paper should be changed dramatically. If it’s a cross-sectional study, they need to add hypothesis before aim. The PECO model should be considered.

2) The topic of dental caries occupies most of introduction section. The authors should make it short.

MATERIALS & METHODS

1) Please add some comments following the STROBE checklist.

2) Children or adolescents? Please unify the expression.

3) The authors stated that “Details on the survey can be found at http://www.hbsc.org.” and “The full protocol of the HBSC studies has been described in previous articles (17-19).” However, the authors should add more details for readers following the STROBE checklist. Furthermore, I could not find any supplemental files. 4) If the authors would like to compare toothbrushing frequency in 2010 and 2014 against 2006, and to investigate whether a temporal association between toothbrushing frequency and its related factors changed over time, the statistical analyses should be changed. The logistic regression models should be revised based on the hypothesis/PECO model.

RESULTS

1) Please add the characteristic table following the STROBE guideline.

2) Please the results based on new methods.

DISCUSSION

1) The data will be changed by new results.

2) The authors cannot use “predictive” and “improve” because this is a cross-sectional study and not cohort study.

3) What is the sentence, “An adequate toothbrushing frequency is the fruit of knowledge (Health literacy) and motivation”? Please revise it appropriately.

4) In a paragraph, there is only one sentence, “All those results match previous results (16).” The authors should revise the part.

5) Please add some comments about limitations, such as a cross-sectional study, no data of important confounders, no generalizability, bias, etc.

6) Please revise the conclusions because this is a cross-sectional study.

Reviewer #3: - it is based on questionnaire data (survey) that may over or under estimate the real tooth brush frequency.

- If the authors presume the incresced toothbrushing frequency in 2014 is related to the educational program, I recommend to mention the subjective evidence uch as statistical analysis.

**********

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: No

Reviewer #3: 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.

PONE-D-20-30886R1

Changes in tooth brushing frequency and its associated factors from 2006 to 2014 among French adolescents: results from three repeated cross sectional HBSC studies

PLOS ONE

Dear Dr. Fernandez de Grado,

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 18 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.

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: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

We look forward to receiving your revised manuscript.

Kind regards,

Frédéric Denis, Ph.D.

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

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: No

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: No

**********

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: No

**********

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: Dear Authors

I extent my sincere thanks for submitting your revised manuscript for the further review. Authors have answered all the queries very nicely. This paper is of excellent merit and it seems fully acceptable for publication in Medicine.

Thank you very much

Reviewer #2: The paper was overall improved. However, there are some issues. The logic is still unclear.

1) The authors answered;

‘Our secondary question was “Among adolescents, what is the effect of associated factors (Diet, Health and body perception, School life, SES) in 2006, compared to 2010 and 2014 on toothbrushing frequency”’.

However, the hypothesis is inappropriate, because the participants were not same. We can only investigate the association between tooth brushing frequency in 2006 and related factors in 2006 but not 2010/2014.

2) The title of table 2 is unclear. Please add more detail comments. What is the odds ratio for? Furthermore, if the dependent value is “Tooth brushing at least twice a day” vs. “Tooth brushing once a day or less” in 2014, the independent values should be the data in 2014 but not 2006/2010. The analyses are inappropriate, even though “all predictors stayed almost constant over the years”. The authors can’t separate the table 2 such as 2a, 2b and 2c, too.

3) What is the mechanism? Do the authors mean that eating breakfast daily, eating fruits daily, eating vegetables daily, wealth perceived, BMI, excellent perceived health, body image, having academic delay, perceived school grades, classmate’s support, being bullied, bullying others is associated with TBF? Are these factors risk for decreasing TBF? If yes, they should show the appropriate references in the introduction and discuss the mechanisms. If no, the logistic regression analyses should be deleted or revised.

4) The authors can’t use the words, “predictors” and “predictive factors”, because this is a cross-sectional study but not a cohort study. If the new results are similar after re-analyses, they may change the conclusion; “Among French adolescents, TBF improved from 2006 to 2014. The TBF was significantly associated with some health behaviors in each year.”

**********

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: Yes: Jun-Beom Park

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.

Changes in tooth brushing frequency and its associated factors from 2006 to 2014 among French adolescents: results from three repeated cross sectional HBSC studies

PONE-D-20-30886R2

Dear Dr. Fernandez de Grado,

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,

Frédéric Denis, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments: