Association of Insomnia with Functional Outcomes Relevant to Daily Behaviors and Sleep-Related Quality of Life among First Nations People in Two Communities in Saskatchewan, Canada

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper investigated the association between insomnia and functional outcomes relevant to daily behaviors and sleep-related quality of life. They concluded that clinical insomnia was significantly associated with functional impairments. This study is worth publishing but reviewer has several questions. 1. There is no significant difference of sleep duration between subjects who had functional impairment and those with no impairments. I wonder why there is no difference. Please make discussion on this point. 2. Authors defined clinical insomnia based on insomnia severity index, but this paper made no descriptions in details of this index. Please add explanation for this index, though in brief. 3. There are marked interindividual variations among optimal sleep duration. If optimal sleep duration of a person was 11 hours, this person felt insomnia when he/she took 9-hour-sleep. This comment is related to my former questions of 1 and 2. Please made description on the variations of optimal sleep duration.  

Author Response

Reviewer 1-Comment 1:

1. There is no significant difference of sleep duration between subjects who had functional impairment and those with no impairments. I wonder why there is no difference. Please make discussion on this point.

Response to Reviewer 1-Comment 1:

In response to the reviewer’s comment, we performed a detailed analysis of sleep duration and functional outcomes.

The National Sleep Foundation is recommended 7-9 hours as the optimal sleep duration for adults [20]. Sleep duration can be categorized into 3 groups: short sleep duration (<7 hours); normal sleep duration (7-9 hours); and long sleep duration (>9 hours).

20: Hirshkowitz M, Whiton K, Albert SM, Alessi C, Bruni O, DonCarlos L, Hazen N, Herman J, Hillard PJA, Katz ES, Kheirandish-Gozal L, Neubauer DN, O’Donnell AE, Ohayon M, Peever J,Rawding R, Sachdeva RC, Setters B, Vitiello MV, Ware JC, National Sleep Foundation’s updated sleep duration recommendations: final report. Sleep Health 2015; 1(4):233-243.

We looked at the mean FOSQ values within the three sleep groups (short sleep, optimal sleep and long sleep).

Sleep Hours	N	Mean FOSQ	Std. Deviation	Minimum	Maximum
<7 hours	81	16.78	3.29	6.25	20.00
7-9 hours	147	17.42	2.90	5.33	20.00
>9 hours	73	17.57	2.37	18.13	20.00

There are slight mean differences of FOSQ among the three sleep groups (short, optimal and long), however, three groups are not statistically significant (p=0.175). The variability of FOSQ is lowest in the long sleep duration group.

Then looked at the association between the functional impairment and sleep duration.

	Functional Impairment
	No n (%)	Yes n (%)
Sleep Hours
<7 hours	41 (50.6)	40 (49.4)
7-9 hours	82 (55.8)	65 (44.2)
>9 hours	38 (52.1)	35 (47.9)

 

Even though there was slightly large proportion of functional impairment in the short sleep duration group (49.4%) and the long sleep duration group (47.9%) compared with the optimal (7-9 hours) sleep duration group (44.2%), they were not statistically significantly different. (p=0.726). There was no difference in functional impairment (49.4% vs 47.9%) between the short and long sleep duration groups (p=0.130).

It is interesting that sleep duration was not associated with functional outcomes. However, these data suggest that subjective sleep duration does not seem to be a major driver of function in the populations we studied. May be the 7-9 hours optimal range was too narrow for these First Nations populations. Whether different results might have been found if we were able to test objective sleep duration is an unanswered question.

The following paragraph is added to the discussion. Please see page 8, paragraph 5, lines 214-226 and Page 9, paragraph 1, lines 227-228.

“There was no significant difference of self-reported sleep duration between participants who had functional impairment and those with no impairments. Further, to this analysis, differences among short, optimal and long sleep durations were compared. The National Sleep Foundation recommends 7-9 hours as the optimal sleep duration for adults [20]. Sleep duration can be categorized into 3 groups: short sleep duration (<7 hours); optimal sleep duration (7-9 hours); and long sleep duration (>9 hours). Even though there was a slightly larger proportion of functional impairment in the short sleep duration group (49.4%) and the long sleep duration group (47.9%) compared with optimal (7-9 hours) sleep duration group (44.2%), there were no statistically significant differences among groups (p=0.726). Also, there was no difference in functional impairment (49.4% vs 47.9%) between the short and long sleep duration groups as well (p=0.130). Therefore, any association between subjective sleep duration and functional impairments were not observed. There could be other factors like cultural, environmental, and behavioral factors influenced the sleep duration. Further studies are needed to confirm this association using objective sleep duration measures.”

Reviewer 1-Comment 2:

2. Authors defined clinical insomnia based on insomnia severity index, but this paper made no descriptions in details of this index. Please add explanation for this index, though in brief.

Response to Reviewer 1-Comment 2: More detailed description of the Insomnia Severity Index is added. Please see page 10, paragraph 2, lines 288-297.

4.2.1 Insomnia Severity Index (ISI) 

The ISI has seven self-reported questions assessing the nature, severity, and impact of insomnia [23-25]. The participants were asked to rate the “current” (that is, the last two weeks) severity of their insomnia problems. The questions measured severity of sleep onset, sleep maintenance, early morning awakening problems, satisfaction with sleep, interference of sleep difficulties with daily functioning, noticeability of sleep problems by others, and distress caused by the sleep difficulties [25]. A 5-point Likert scale was used to rate each question, yielding a total score ranging from 0 to 28. The total score was interpreted as follows: absence of insomnia (0-7), sub-threshold insomnia (8-14), moderate insomnia (15-21), and severe insomnia (22-28) [25]. Clinical insomnia was identified if the score was equal to or greater than 15, that the ISI score was ≥15 [24].

Reviewer 1-Comment 3:

3. There are marked interindividual variations among optimal sleep duration. If optimal sleep duration of a person was 11 hours, this person felt insomnia when he/she took 9-hour-sleep. This comment is related to my former questions of 1 and 2. Please made description on the variations of optimal sleep duration.  

Response to Reviewer 1-Comment 3:

This comment is addressed in Response to Reviewer 1-Comment 1.

Reviewer 2 Report

Comments and Suggestions for Authors

This article is a report of the follow-up survey of the First Nations Sleep Health Project (FNSHP). The primary objective of the FNSHP was to examine the associations between sleep disorders, risk factors, and comorbidities, and to assess local diagnosis and treatment. The reported follow-up study focused on the association of insomnia with functional outcomes related to daily behaviors and sleep-related quality of life using the Functional Outcomes of Sleep Questionnaire (FOSQ-10). The study was carefully planned and conducted with the participation of research assistants from each community, which ensured good contact with the participants during the interview. The questionnaire also included questions to obtain information on the socio-demographic situation of the participants, education, body weight, health behaviors (smoking, physical activity), prescription medication use, number of hours of sleep, the occurrence of clinical insomnia, excessive daytime sleepiness, and loud snoring. Based on statistical analysis, the authors found that after adjusting for age, excessive daytime sleepiness, sex, regular use of prescription medication, and loud snoring, the presence of clinical insomnia was significantly associated with functional impairments relevant to daily behaviors and sleep-related quality of life. A person with clinical insomnia, women, and regular use of prescription medications was also associated with an increased risk of functional impairments.

The authors emphasize that this study is the first to investigate functional impairments relevant to daily behaviors and sleep-related quality of life in adults living in two rural Cree First Nation communities in Saskatchewan, Canada. I do not believe that the only important issue is the fact that the study was conducted. The most important thing is the purpose for which the study is conducted and what its results are intended to serve.

Although this article is intended by the authors to be a simple account of the conducted research, it is worth considering, in my opinion, to what extent the problem of insomnia and other analyzed indicators of health status in the studied population (Indigenous peoples) differ from the national rate. Furthermore, I believe that the terms "Community A and Community B" should not be used to describe the study group.

Author Response

Reviewer 2-Comment 1:

This article is a report of the follow-up survey of the First Nations Sleep Health Project (FNSHP). The primary objective of the FNSHP was to examine the associations between sleep disorders, risk factors, and comorbidities, and to assess local diagnosis and treatment. The reported follow-up study focused on the association of insomnia with functional outcomes related to daily behaviors and sleep-related quality of life using the Functional Outcomes of Sleep Questionnaire (FOSQ-10). The study was carefully planned and conducted with the participation of research assistants from each community, which ensured good contact with the participants during the interview. The questionnaire also included questions to obtain information on the socio-demographic situation of the participants, education, body weight, health behaviors (smoking, physical activity), prescription medication use, number of hours of sleep, the occurrence of clinical insomnia, excessive daytime sleepiness, and loud snoring. Based on statistical analysis, the authors found that after adjusting for age, excessive daytime sleepiness, sex, regular use of prescription medication, and loud snoring, the presence of clinical insomnia was significantly associated with functional impairments relevant to daily behaviors and sleep-related quality of life. A person with clinical insomnia, women, and regular use of prescription medications was also associated with an increased risk of functional impairments.

Response to Reviewer 2-Comment 1:

Thank you.

Reviewer 2-Comment 2:

The authors emphasize that this study is the first to investigate functional impairments relevant to daily behaviors and sleep-related quality of life in adults living in two rural Cree First Nation communities in Saskatchewan, Canada. I do not believe that the only important issue is the fact that the study was conducted. The most important thing is the purpose for which the study is conducted and what its results are intended to serve.

Response to Reviewer 2-Comment 2:

The following statement is added to the strengths section to highlight the importance of the project. Please see page 9, paragraph 3, lines 241-244.

“This project provides evidence of the sleep disorders among First Nation communities and the information obtained from the First Nations Sleep Health Project will help to promote awareness about sleep health among First Nations peoples and aid in prevention and treatment measures.”

Reviewer 2-Comment 3:

Although this article is intended by the authors to be a simple account of the conducted research, it is worth considering, in my opinion, to what extent the problem of insomnia and other analyzed indicators of health status in the studied population (Indigenous peoples) differ from the national rate. Furthermore, I believe that the terms "Community A and Community B" should not be used to describe the study group.

Response to Reviewer 2-Comment 3:

Discussion of insomnia prevalence among First Nations and general Canadians were added. Please see page 9, paragraph 2, lines 229-237.

“A study conducted by Morin et al. surveyed 2000 Canadians aged 18 and older about their sleep patterns and found that 13.4% reported experiencing insomnia [3]. In Canada, it is estimated that 23.8% of adults experience nighttime insomnia symptoms [6]. The prevalence of insomnia varies depending on the definition used. According to the definition of the Insomnia Severity Index (ISI), the study reported that the prevalence of insomnia among First Nations people was 19.2%-21.0% in baseline and follow-up studies, respectively. Insomnia symptoms significantly contribute to the economic burden of illness in Canada [6]. Reducing insomnia symptoms in the First Nations population could potentially benefit the quality of life of these populations.”

3. Morin CM, LeBlanc M, Bélanger L, Ivers H, Mérette C, Savard J. Prevalence of Insomnia and its Treatment in Canada. The Canadian Journal of Psychiatry. 2011;56(9):540-548. doi:1177/070674371105600905

6. Chaput JP, Janssen I, Sampasa-Kanyinga H, Carney CE, Dang-Vu TT, Davidson JR, Robillard R, Morin CM. Economic burden of insomnia symptoms in Canada. Sleep Health. 2023 Apr;9(2):185-189. doi: 10.1016/j.sleh.2022.09.010. Epub 2022 Oct 29. PMID: 36319579.

The terms (Community A and Community B) described to identify the study groups were decided by the two study groups without disclosing their community names. We need to respect their view, and no changes were made.