PONE-D-20-29557

Possible favorable lifestyle changes owing to the coronavirus disease 2019 (COVID-19) pandemic among middle-aged Japanese women: an ancillary survey of the TRF-Japan study, using the original “Taberhythm” smartphone app

PLOS ONE

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Reviewers' comments:

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Comments to the Author

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

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Reviewer #1: Partly

Reviewer #2: Yes

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

Reviewer #1: Yes

Reviewer #2: Yes

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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: Yes

Reviewer #2: Yes

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Reviewer #1: No

Reviewer #2: Yes

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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: Review PONE-D-20-29557

Possible favorable lifestyle changes owing to the coronavirus disease 2019 (COVID-19) pandemic among middle-aged Japanese women: an ancillary survey of the TRFJapan study, using the original “Taberhythm” smartphone app

The objective of the study was to compare lifestyle data between periods before and after the start of the COVID-19 pandemic, to objectively assess lifestyle changes during quarantine. A total of 464 smartphone users (346 women, 35±12 years old, body mass index [BMI] 23.4±4.5) participated in period A (7 January to 28 April 2019) and 622 smartphone users (533 women, 32±11 years old, BMI 23.3±4.0) participated during period B (6 January to 26 April 2020).

General comment

It is important to assess changes in lifestyles during the COVID-19 pandemics but the present study is somewhat confusing and difficult to read due to an excessive use of figure and poor phrasing. Overall, the data presented must be greatly simplified for clarity. Figures 1, 3a, 3b, 3c and 4 should include two separate line (A and B) and lesser values on the X-axis. Figure 2a and 2b should be removed (correlation coefficient is enough). Figure S3 is unreadable. Also, there are only 9 references cited in the whole manuscript, indicating that authors failed to properly review the others studies on the COVID-19 consequences, the use of app to collect data, the influence of sociodemographic variables on lifestyles, the feeling of happiness, and so on…As a result, the introduction, the research question and the study objectives are quite poorly developed. Consequently, the discussion is too short and quite mundane.

Specific comments:

The introduction lacks of a sound theoretical framework. Many studies have been published since March 2020 about the effects of COVID-19 pandemics and confinement on lifestyles and mental health in the general population. Also studies investigating the added value of health-related app to collect data on lifestyles should be mentioned to justify the interest of the present study, and the research question.

Please replace “individuals” with “participants” in the text.

Line 86: We applied the Taberhythm app to collect objective data and assess lifestyle changes during quarantine by comparing periods before and after the COVID-19 pandemic” However, only the number of step per day can be considered as “objective measure”. Please reformulate.

Line 95. “Our findings can be helpful in suggesting positive lifestyle habits that can be adopted during quarantine periods in the ongoing COVID-19 pandemic” this sentence anticipate the result. Replace this sentence with clear study objectives, based on properly documented instroduction.

Inclusion and exclusion criteria must be clarified. The characteristics of the main study participants should be mentioned.

The study design must be specified

It is unclear whether or not the same participants were included in waves A et B.

Line 165: “Because we wished to focus on lifestyle changes owing to teleworking and school closures, we hypothesized that women and men age 30–50 years were most affected by the COVID-19 stay-at-home policies. Therefore, we analyzed these individuals separately”. The evidence (data) underlying this hypothesis must be mentioned in the introduction.

Also, authors performed descriptive analyses separated by sex. This must be justified in the introduction. And waves A and B should be in columns, while covariates (sex…) in row, for clarity.

The results are confusing and difficult to read, as mention in general comments.

As mentioned before, the discussion should be more developed based on presented results, theoretical inputs, and insights from previous studies.

Reviewer #2: This paper investigates how COVID-19 has affected people’s lifestyle, in particular, eating, walking, and the sense of happiness. This is done by analysing and comparing data collected in 2019 and 2020 through a smartphone app Taberhythm. While this topic is of general interests and considerable social implications, the authors may need to clarify or improve upon the points listed below.

1) It is not clear to readers why the authors chose the starting date to be early January, given that Japanese governments put forward recommendations in mid Feb 2020. The inclusion of the period where COVID-19 was much less of concern may complicate the analysis and results.

2) The authors need to specify the reason why they believe the decline in eating duration was a result of earlier eating

3) the authors wrote, “younger women (age 20–25 years) participated in the study slightly more than during January to April 2020 (Period B) than during January to April 2019 (Period A); therefore, participants’ mean age in Period B was a few years younger than in the previous year (32±11 vs. 35±12 years old, p<0.05).”

I am not sure if it can be concluded that the overall younger age was due to a higher number of people in very specific age range (20 – 25 yrs). Plus, there are more women enrolled in 2020 anyway.

4) The authors need to be made aware of a work done in Europe covering very similar behaviours such as bedtime and walking, entitled ‘Using Smartphones and Wearable Devices to Monitor Behavioral Changes During COVID-19’. It would be interesting to compare these results in different continents and cultures.

5) the authors need to increase the resolution of all figures. It is hard to see details at the moment. It is also necessary to reconsider the presentation of Figure 1,3,4. The boxes are significantly overlapping, making it very difficult for readers to read.

6) There are occasional grammatical errors the authors need to correct

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Reviewer #1: No

Reviewer #2: No

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Possible favorable lifestyle changes owing to the coronavirus disease 2019 (COVID-19) pandemic among middle-aged Japanese women: An ancillary survey of the TRF-Japan study using the original “Taberhythm” smartphone app

PONE-D-20-29557R1

Dear Dr. Azuma,

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.

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Kind regards,

John William Apolzan, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

If the authors wish to further clarify the eating duration term, they can but overall seems sufficient.

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)

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

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

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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: No

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #2: The definition of eating duration is somewhat confusing. One would expect the total amount of time spent on eating. I am not sure how the authors intend to make sense of this parameters. The authors may consider elaborating it more, and preferably using another term with less ambiguity.

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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: Aymery Constant

Reviewer #2: No