Meal and Sleep Timing before and during the COVID-19 Pandemic: A Cross-Sectional Anonymous Survey Study from Sweden

Round 1

Reviewer 1 Report

I think the manuscript can be published in its present form. However, it is desirable the authors to cite and discuss in the manuscript the following articles related to the manuscript's subject of investigation:

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523687/ (The effects of COVID-19 quarantine on eating and sleeping)
2. https://pubmed.ncbi.nlm.nih.gov/33137947/ (Eating Habits and Lifestyle during COVID-19 Lockdown in the United Arab Emirates: A Cross-Sectional Study)
3. https://ideas.repec.org/a/gam/jscscx/v10y2021i1p27-d482200.html (What about the “Social Aspect of COVID”? Exploring theDeterminants of Social Isolation on the Greek Populationduring the COVID-19 Lockdown)
4. https://www.sciencedirect.com/science/article/pii/S1474442220304567?via%3Dihub (Sleep research in 2020: COVID-19-related sleep disorders)
5. https://pubmed.ncbi.nlm.nih.gov/33108269/ ( Sleep problems during the COVID-19 pandemic by population: a systematic review and meta-analysis)
6. https://jcsm.aasm.org/doi/10.5664/jcsm.8524 (Insomnia and psychological reactions during the COVID-19 outbreak in China)

Author Response

Comment 1: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523687/ (The effects of COVID-19 quarantine on eating and sleeping)

Authors’ response: We cite the study in the revised version of our article.

Comment 2: https://pubmed.ncbi.nlm.nih.gov/33137947/ (Eating Habits and Lifestyle during COVID-19 Lockdown in the United Arab Emirates: A Cross-Sectional Study)

Authors’ response: We briefly discuss and cite the study in the revised version of our article.

Comment 3: https://ideas.repec.org/a/gam/jscscx/v10y2021i1p27-d482200.html (What about the “Social Aspect of COVID”? Exploring theDeterminants of Social Isolation on the Greek Populationduring the COVID-19 Lockdown)

Authors’ response: We cite the study in the revised version of our article.

Comment 4: https://www.sciencedirect.com/science/article/pii/S1474442220304567?via%3Dihub (Sleep research in 2020: COVID-19-related sleep disorders)

Authors’ response: We cite the study in the revised version of our article.

Comment 5: https://pubmed.ncbi.nlm.nih.gov/33108269/ ( Sleep problems during the COVID-19 pandemic by population: a systematic review and meta-analysis)

Authors’ response: We cite the study in the revised version of our article.

Comment 6: https://jcsm.aasm.org/doi/10.5664/jcsm.8524 (Insomnia and psychological reactions during the COVID-19 outbreak in China)

Authors’ response: We cite the study in the revised version of our article.

Reviewer 2 Report

The work presents, in my opinion, great limitations for its publication. On the one hand, they should improve the introduction by clearly including hypotheses. They must indicate the criteria for selecting the sample. They must indicate the reliability and validity factors of the instruments used (alpha and omega). The analyzes used should be reviewed, and replaced by a before and after analysis. Currently the work lacks data that analyze lay before and after. This way they will be able to respond to the objectives of the work. The analyzes they carry out do not make sense or contribute to the investigation.

Author Response

REVIEWER 2

Comment 1: The work presents, in my opinion, great limitations for its publication. On the one hand, they should improve the introduction by clearly including hypotheses. They must indicate the criteria for selecting the sample. They must indicate the reliability and validity factors of the instruments used (alpha and omega). The analyzes used should be reviewed, and replaced by a before and after analysis. Currently the work lacks data that analyze lay before and after. This way they will be able to respond to the objectives of the work. The analyzes they carry out do not make sense or contribute to the investigation.

Authors’ response: In response to your feedback and those of the other reviewers, the introduction section has undergone significant revisions. At the end of the introduction section, we now also specify our hypotheses.

Please note that like many similar surveys, no selection criteria were possible to apply – the online survey was publicly accessible (this has now been clarified in the revised version of our manuscript). As requested, we investigated the internal consistency of the questions related to sleep and meal timing. This analysis indicates good internal consistency and is now reported in section 4.1.

Regarding your concerns related to our analysis: Please note that the present analysis's main purpose was to investigate whether a) sleep and b) meal timing would differ between the time points of interest, i.e., before and during the pandemic. We have nevertheless expanded our results section:

• We now report that sleep and meal timing parameters did differ between working and free days,
• We specify that this holds both before and during the pandemic.

Altogether, we hope that the revised version of our manuscript (including changes to comments raised by the other reviewers) has satisfactorily addressed your concerns.    

Reviewer 3 Report

I have the following comments for the authors to address and I am happy to review this paper again.

1) The authors stated "The novel coronavirus SARS-CoV-2, the causative agent of Coronavirus disease 2019 (COVID-19), emerged at the end of 2019 in China and has since spread across the world [1]." This statement may not be totally correct. Recent reports showed that novel coronavirus was circulated in Italy before it was identified in China. The correct way to say this sentence is that it was first identified in China and not emerged. It was spread in Europe and Asia in late 2019. Please refer to the following reference that discovers the novel coronavirus in Italy in September 2019. 

https://www.reuters.com/article/health-coronavirus-italy-timing-idUSKBN27W1J2

2)  The authors stated ", many countries  worldwide have taken action to slow the spread of the virus, including stay-at-home and  work-from-home orders." They should mention specifically the effect of lockdown and social distancing on mental health during the pandemic. Please go the Pubmed and search for studies that report on lockdown and social distancing:

Search term 1: Anxiety and Depression Among People Under the Nationwide Partial Lockdown 

Search term 2: The domain of Anxiety/Depression had the highest proportion of reporting any problems in National Social distancing

3) The authors stated, "a study from Europe found that COVID-19-related restrictions, especially a lockdown, resulted in delayed bedtime, later rise times, increased sleep duration, and reduced social jetlag (shifts in sleep timing between workdays and free days) [4] – as also confirmed in a U.S. cohort". They should mention Asia and outside of the US and Europe. Please go to the Pubmed and search for supporting references from other countries:

Search term 1: More than one-quarter of psychiatric patients suffered from moderately severe to severe insomnia

Search term 2: workers reported a prevalence of anxiety (3.8%), depression (3.7%), stress (1.5%) and insomnia (2.3%) during the pandemic

Please highlight the relationship between anxiety, depression, stress and insomnia during the pandemic based on studies published in Pubmed.

3) Under discussion, the authors need to stress that although there was statistically significant difference, it was not that different clinically. For example,

Bedtime (hh:mm) 22:40 (00:55) 22:53 (01:05) <0.001

There was only a 13-minute difference before and after the onset of the pandemic although p-value was less than 0.001. 13-minute delay is not considered to be a major delay for most people.

4) The authors should propose how to treat insomnia during the pandemic. Due to the minimization of social contact, online psychotherapy such as digital cognitive behaviour therapy (dCBT) can treat insomnia. Please go the Pubmed and search studies that provides strong support for the effectiveness of dCBT in treating insomnia. 

5) Under limitations, please state that there is a lack of information on the occupational background of participants. Do they work for shift work such as healthcare workers? If such information is unavailable, please state it as a limitation.

Author Response

Comment 1: The authors stated "The novel coronavirus SARS-CoV-2, the causative agent of Coronavirus disease 2019 (COVID-19), emerged at the end of 2019 in China and has since spread across the world [1]." This statement may not be totally correct. Recent reports showed that novel coronavirus was circulated in Italy before it was identified in China. The correct way to say this sentence is that it was first identified in China and not emerged. It was spread in Europe and Asia in late 2019. Please refer to the following reference that discovers the novel coronavirus in Italy in September 2019. https://www.reuters.com/article/health-coronavirus-italy-timing-idUSKBN27W1J2

Authors’ response: Thanks for the hint! We have rephrased the first sentence accordingly.

Comment 2:  The authors stated ", many countries  worldwide have taken action to slow the spread of the virus, including stay-at-home and  work-from-home orders." They should mention specifically the effect of lockdown and social distancing on mental health during the pandemic. Please go the Pubmed and search for studies that report on lockdown and social distancing: Search term 1: Anxiety and Depression Among People Under the Nationwide Partial Lockdown Search term 2: The domain of Anxiety/Depression had the highest proportion of reporting any problems in National Social distancing

Authors’ response: As advised by you, we now state that “many countries worldwide have taken action to slow the spread of the virus, including stay-at-home, work-from-home, and social distancing orders. These social restrictions have come at a cost, including reports of reduced well-being, increasing mental health issues, and lower physical activity levels”. In this context, we also cite relevant literature.

Comment 3: The authors stated, "a study from Europe found that COVID-19-related restrictions, especially a lockdown, resulted in delayed bedtime, later rise times, increased sleep duration, and reduced social jetlag (shifts in sleep timing between workdays and free days) [4] – as also confirmed in a U.S. cohort". They should mention Asia and outside of the US and Europe. Please go to the Pubmed and search for supporting references from other countries: Search term 1: More than one-quarter of psychiatric patients suffered from moderately severe to severe insomnia Search term 2: workers reported a prevalence of anxiety (3.8%), depression (3.7%), stress (1.5%) and insomnia (2.3%) during the pandemic

Authors’ response: Great point! In order to paint a more nuanced picture of how the COVID-19 pandemic may have changed sleep among humans, we have expanded the introduction as follows:

“Due to greater time flexibility, people may be less stressed by work schedules, thereby having the opportunity to align better their daily activities with their individual sleep/wake preference. Supporting this assumption, a study from Europe found that COVID-19-related restrictions, especially a lockdown, resulted in delayed bedtime, later rise times, increased sleep duration, and reduced social jetlag (shifts in sleep timing between workdays and free days) [4] – as also confirmed in a U.S. cohort [5]. Despite this evidence, it must be borne in mind that not all studies support the notion of improved sleep during the pandemic. For instance, an increasing number of psychiatric patients complain about severe insomnia as a result of the pandemic and related restrictions (PMID 32353518). Finally, in light of emerging evidence suggesting that COVID-19 can affect the brain (DOI: 10.1017/S1092852920002175), it is also possible that some sleep changes observed among people during the pandemic may have been a result of symptomatic and asymptomatic COVID-19.”

Comment 4: Please highlight the relationship between anxiety, depression, stress and insomnia during the pandemic based on studies published in Pubmed.

Authors’ response: As detailed in our response to your comment 3, we cite and describe research suggesting that the pandemic and related restrictions may have caused sleep problems and that these associations were particularly observed among psychiatric patient populations. In light of the scope of our article, we do not feel that further elaborating on the relationship between anxiety, depression, stress, and insomnia would provide a better context to understand the rationale of our study (i.e., did sleep and meal timing change during compared to before the COVID-19 pandemic).

Comment 5: Under discussion, the authors need to stress that although there was statistically significant difference, it was not that different clinically. For example, Bedtime (hh:mm) 22:40 (00:55) 22:53 (01:05) <0.001 There was only a 13-minute difference before and after the onset of the pandemic although p-value was less than 0.001. 13-minute delay is not considered to be a major delay for most people.

Authors’ response: As requested, we now highlight at the beginning of the discussion that the observed changes were relatively small.

Comment 6: The authors should propose how to treat insomnia during the pandemic. Due to the minimization of social contact, online psychotherapy such as digital cognitive behaviour therapy (dCBT) can treat insomnia. Please go the Pubmed and search studies that provides strong support for the effectiveness of dCBT in treating insomnia. 

Authors’ response: We agree with you that online CBT for insomnia could be highly useful to treat insomnia during the pandemic, especially in light of social distancing orders. Nevertheless, in our view, adding this information to the discussion of the present article appears not justifiable, as we did not study insomnia. 

Comment 7: Under limitations, please state that there is a lack of information on the occupational background of participants. Do they work for shift work such as healthcare workers? If such information is unavailable, please state it as a limitation.

Authors’ response: We have expanded the limitation section accordingly.

Reviewer 4 Report

In the present study the Authors in 191 adults from Sweden whether the COVID-19 pandemic shifted people’s sleep schedule and meal timing toward later hours of the day. They remarked that, at the time of the survey (during the flattening of the first wave of the pandemic), the Swedish Public Health Agency encouraged all Swedish residents to work from home whenever possible. On the basis of previous observations, the Authors hypothesized that respondents would have a delayed bedtime, sleep midpoint and wake-up time, but also sleep longer, during the pandemic compared with the pre-pandemic period. They further expected that the delayed sleep schedule would be associated with a daily eating time window shifted to later hours.

Overall, I found the present study timely, well conducted, very interesting and scientifically sound: enjoyed reading it!. I have only some minor comments aimed to improve the high quality of the paper and these are outlined below:

1) In the introduction it should be specified that disrupted patterns may be found also in recovered COVID patients and might be related to a possible neurotropism of SARS-CoV-2 (please, see and cite doi: 10.1017/S1092852920002175).

2) Concerning paragraph 2.1, please add some more information on exact time frame, on how the sample was recruited, how many subjects were screened and refused to participate or excluded and more informations that would be useful for the reader,

3) The Author wrote that "...an anonymous online survey study…" was conducted. Please, add some more informations on the used Platform and on the structure of online survey.

4) I suggest to add the full statistics in Table 1 rather than merely "p".

Author Response

Comment 1: In the introduction it should be specified that disrupted patterns may be found also in recovered COVID patients and might be related to a possible neurotropism of SARS-CoV-2 (please, see and cite doi: 10.1017/S1092852920002175).

Authors' response: In the revised version of our manuscript, we refer to the suggested study and highlight that the virus's central nervous effects may partially explain sleep changes observed in response to the COVID-19 pandemic.

Comment 2: Concerning paragraph 2.1, please add some more information on exact time frame, on how the sample was recruited, how many subjects were screened and refused to participate or excluded and more informations that would be useful for the reader,

Authors' response: We have expanded section 2.1. accordingly.

Comment 3: The Author wrote that "...an anonymous online survey study…" was conducted. Please, add some more informations on the used Platform and on the structure of online survey.

Authors' response: In the revised version, we provide more information about the platform and its structure. 

Comment 4: I suggest to add the full statistics in Table 1 rather than merely "p".

Authors' response: We have expanded Table 1 accordingly.

Round 2

Reviewer 1 Report

I think the manuscript can be published in its present form. 

Reviewer 2 Report

The work continues to be questionable regarding some aspects: they continue without indicating the omega of the instruments used. The statements made regarding the results obtained are very daring. The data analyzes carried out do not allow us to make the type of statements or conclusions that the authors indicate. A correlation does not imply a cause. They have a sample that allows for before and after analysis, but they don't. I do not understand, and I cannot accept that the change is affirmed before and after with a correlation.

Reviewer 3 Report

Reviewer 4 Report

The paper is very interesting and scientifically sound. It’s worthy of publication