Sleep Efficiency and Sleep Onset Latency in One Saskatchewan First Nation
, Punam Pahwa 1,2, Shelley Kirychuk 1,3, Mark Fenton 3, Vivian R. Ramsden 4, Jeremy Seeseequasis 1, Warren Seesequasis 5, Robert Skomro 3, Donna C. Rennie 6, Kathleen McMullin 1, Brooke P. Russell 1, Niels Koehncke 1,3, Sylvia Abonyi 2, Malcolm King 2 and James A. Dosman 1,3
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThank you for this important research and identifies a public health problem. After seeing that sleep duration was lower in this tribe than in the general Canadian population, I would ask that you insert a bit in the intro and the discussion on what is known about the psych, cardiovascular, and metabolic effects that are known to be associated with lower sleep duration.
One aspect was surprising to me: putting results into 2nd place and methods into 4th place in the ms. This is counter to the usual and is a bit of a stumbling block to interpreting the results with one reading.
Methods tells the years when the study was done, but can you add the season(s) when actigraphy was done? It's apparently not important in the general Canadian population ( Zolfghari et al, Neurology 2023, e74-82), but you've already this population is an outlier in sleep parameters.
One correction: Discussion line 118 - should "good" or "high" be added before s"leep efficiency" ?
Comments on the Quality of English Languagenone
Author Response
Comments from Reviewer 1
Comment 1:
Thank you for this important research and identifies a public health problem. After seeing that sleep duration was lower in this tribe than in the general Canadian population, I would ask that you insert a bit in the intro and the discussion on what is known about the psych, cardiovascular, and metabolic effects that are known to be associated with lower sleep duration.
Response: Association between shorter sleep duration and psych, cardiovascular, and metabolic effects are addressed in the introduction and discussion. Please see page 2, lines 56-58 and page 12, lines 219-222.
One aspect was surprising to me: putting results into 2nd place and methods into 4th place in the ms. This is counter to the usual and is a bit of a stumbling block to interpreting the results with one reading.
Response: Methods are placed on the 4th place according to the Journal requirements. However, as you suggested I have moved the method section to the 2nd place.
Methods tells the years when the study was done, but can you add the season(s) when actigraphy was done? It's apparently not important in the general Canadian population (Zolfghari et al, Neurology 2023, e74-82), but you've already this population is an outlier in sleep parameters.
Response: I have added the periods when the actigraphy was done. Please see section 2.2.1 clinical measurements page 3, line 115.
One correction: Discussion line 118 - should "good" or "high" be added before “sleep efficiency" ?
Response: These statements are revised. Please see response to comment from reviewer 2. Please see page 11, lines 212-216.
Comments on the Quality of English Language none
Reviewer 2 Report
Comments and Suggestions for AuthorsReview for clockssleep-2769318
The authors have collected objective and subjective sleep data, actigraphy and PSQI, from Cree First Nation to evaluate and compare sleep latency (SL) and efficiency (SE) with reference values.
Major comments:
One major shortcoming of this work is that the actigraphy data was collected for a single night for each subject. Authors briefly point to this in the article. Please discuss this shortcoming in greater details and how it might have affected the outcome of this work.
Line# 78-80, authors indicate a significant difference between subjective and objective measurement of SE. This is in fact reported elsewhere in literature. As such, when comparing the SE measured in this article to a reference value, care should be taken to make sure that the same methodology, i.e., objective (actigraphy) vs subjective, was used for this measurement.
Minor comments:
Line#175-177, authors state “When sleep duration and sleep efficiency were assessed together, sleep efficiency was associated with daytime systolic blood pressure and sleep duration was associated with nighttime blood pressure [18]. This current study supports the evidence.” This implies that the authors measured or somehow had access to both daytime and night-time blood pressure for their subjects. Is that the case? Is the blood pressure in Table 3 a night-time or a daytime value?
In Table 3, two P values are reported. What comparison is being reported for the first P value?
Authors report a lower SE and higher SL compared to reference values. Any thoughts on why this is the case? Could you please discuss what factors could be contributing to this?
Please provide the sleep parameters calculated based on PSQI in a table.
Do authors have any hypothesis as to why they measured lower SE and longer SL in 18-54 y group compared to those 54y and older?
It might be more meaningful to look at some of the associations reported in Table 3 using sleep parameters derived from PSQI as opposed to actigraphy, especially since the actigraphy data was collected on a single night, for example, when looking at factors such as using sleep medications, waking up during the night due to nightmares, or waking up and getting out of bed.
The quality of English and technical writing in this article is somewhat awkward. For example, authors state “the prevalence of sleep efficiency was …” when the proper terminology would be “the prevalence of sleep efficiency of < 85% was 55.1%”, or something of that order. Sleep efficiency is just a terminology and as such doesn’t have an inherent prevalence, but poor SE is a condition and thus has a prevalence.
At the top of the page 3 in Table 2, I think the authors meant to say, “onset latency” and not “on set latency”
Comments on the Quality of English LanguageThe quality of English and technical writing in this article is somewhat awkward. For example, authors state “the prevalence of sleep efficiency was …” when the proper terminology would be “the prevalence of sleep efficiency of < 85% was 55.1%”, or something of that order. Sleep efficiency is just a terminology and as such doesn’t have an inherent prevalence, but poor SE is a condition and thus has a prevalence.
Author Response
Comments from Reviewer 2
The authors have collected objective and subjective sleep data, actigraphy and PSQI, from Cree First Nation to evaluate and compare sleep latency (SL) and efficiency (SE) with reference values.
Major comments:
One major shortcoming of this work is that the actigraphy data was collected for a single night for each subject. Authors briefly point to this in the article. Please discuss this shortcoming in greater details and how it might have affected the outcome of this work.
Response: details were added to the limitations section. Please see page 13, lines 299-300.
Line# 78-80, authors indicate a significant difference between subjective and objective measurement of SE. This is in fact reported elsewhere in literature. As such, when comparing the SE measured in this article to a reference value, care should be taken to make sure that the same methodology, i.e., objective (actigraphy) vs subjective, was used for this measurement.
Response: This statement is revised to indicate the objective (actigraphy) and subjective (using PSQI) measurements. Please see page 4, lines 166-170.
Minor comments:
Line#175-177, authors state “When sleep duration and sleep efficiency were assessed together, sleep efficiency was associated with daytime systolic blood pressure and sleep duration was associated with nighttime blood pressure [18]. This current study supports the evidence.” This implies that the authors measured or somehow had access to both daytime and night-time blood pressure for their subjects. Is that the case? Is the blood pressure in Table 3 a night-time or a daytime value?
Response: Sorry for the confusion. This statement is revised to remove the confusion. We do not have day time and night time measured blood pressures. We only have self-reported question about “have you ever had blood pressure”.
In Table 3, two P values are reported. What comparison is being reported for the first P value?
Response: the first p value reported from Chi-squared Test for measuring the association between outcome and independent factor. Second p value is reported from the binary logistic regression analysis results. Details were included to the Table 3.
Authors report a lower SE and higher SL compared to reference values. Any thoughts on why this is the case? Could you please discuss what factors could be contributing to this?
Response: The sleep patterns of this population could be different from the general population. Many reasons could be attributed to poor sleep including a sleep disorder, a poor sleep environment, or another health condition.
Please provide the sleep parameters calculated based on PSQI in a table.
Response: The sleep parameters calculated based on PSQI are included to the Table 2.
Do authors have any hypothesis as to why they measured lower SE and longer SL in 18-54 y group compared to those 54y and older?
Response: The hypothesis is to compare older age group with 18-54 years age group
It might be more meaningful to look at some of the associations reported in Table 3 using sleep parameters derived from PSQI as opposed to actigraphy, especially since the actigraphy data was collected on a single night, for example, when looking at factors such as using sleep medications, waking up during the night due to nightmares, or waking up and getting out of bed.
Response: I agreed with your suggestion. However, we have published similar results from the PSQI survey questionnaire, the paper entitled “Duration and quality of sleep in 2 rural Cree First Nation communities in Saskatchewan, Canada” in Sleep Health Journal we are not planning to duplicate it. Intent of this paper was to present the objective clinical results.
The quality of English and technical writing in this article is somewhat awkward. For example, authors state “the prevalence of sleep efficiency was …” when the proper terminology would be “the prevalence of sleep efficiency of < 85% was 55.1%”, or something of that order. Sleep efficiency is just a terminology and as such doesn’t have an inherent prevalence, but poor SE is a condition and thus has a prevalence.
Response: These statements are revised. Please see page 11, lines 212-216.
At the top of the page 3 in Table 2, I think the authors meant to say, “onset latency” and not “on set latency”
Response: Thank you. The spellings are corrected.
Comments on the Quality of English Language
The quality of English and technical writing in this article is somewhat awkward. For example, authors state “the prevalence of sleep efficiency was …” when the proper terminology would be “the prevalence of sleep efficiency of < 85% was 55.1%”, or something of that order. Sleep efficiency is just a terminology and as such doesn’t have an inherent prevalence, but poor SE is a condition and thus has a prevalence.
Response: These statements are corrected. Please see page 11, lines 212-216.
