Introduction
Methods
Study design and sampling (sample 1)
Minimal sample size calculation
Data collection and measurement
Insomnia scales
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The AIS is composed of 8 items that self-assesses the intensity of sleep induction, awakenings, sleep duration and quality, etc [40] Scores ≥6 would indicate the presence of insomnia.
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The ISI is composed of 7 items designed to assess the intensity of insomnia and its negative effect on daily work, quality of life and other concerns about sleep disturbances [41].
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The RIS includes ten items and is a self-reported tool aiming at measuring the psychological aspect of insomnia [14].
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The MOS-SS is a 12-item, self-reporting instrument for evaluating sleep outcomes [43]. In all scales, higher scores reflect worse sleep problems/sleep quality.
Sample 2
Statistical analysis
Results
Study 1
Frequency (%) | ||
---|---|---|
Gender | Male | 272 (36.0%) |
Female | 484 (64.0%) | |
Living alone | Yes | 60 (7.9%) |
No | 696 (92.1%) | |
Education level | Primary | 2 (0.3%) |
Complementary | 39 (5.2%) | |
Secondary | 210 (27.8%) | |
University | 505 (66.8%) | |
Monthly salary | No income | 238 (31.5%) |
Less than 450 USD | 75 (9.9%) | |
450–1000 USD | 237 (31.3%) | |
1000–2000 USD | 162 (21.4%) | |
> 2000 USD | 44 (5.8%) | |
District | Beirut | 203 (26.9%) |
Mount Lebanon | 460 (60.8%) | |
North Lebanon | 36 (4.8%) | |
South Lebanon | 44 (5.8%) | |
Bekaa | 13 (1.7%) | |
Marital status | Single | 409 (54.1%) |
Married | 292 (38.6%) | |
Divorced | 22 (2.9%) | |
Widowed | 33 (4.4%) | |
Smoking | Yes | 160 (21.2%) |
No | 596 (78.8%) | |
Waterpipe | Yes | 175 (23.1%) |
No | 581 (76.9%) | |
Mean ± SD | ||
Age (in years) | 37.00 ± 15.54 | |
Alcohol to sleep | 0.12 ± 0.89 | |
Body Mass Index (Kg/m2) | 25.04 ± 4.34 |
Study 2
Scale’s structure
Factor | Items | Factor 1 | Factor 2 | Factor 3 | Factor 4 | Factor 5 |
---|---|---|---|---|---|---|
I am afraid to go to bed because of my disturbed sleep | RIS 8 | .820 | ||||
I think a lot about my sleep | RIS 7 | .744 | ||||
I feel that I have not slept all night | RIS 6 | .721 | ||||
I wake up from the slightest sound | RIS 5 | .657 | ||||
Awaken short of breath or with a headache? | MOS-SS 5 | .640 | ||||
Sleep induction | AIS 2 | .846 | ||||
Awakenings during the night | AIS 1 | .778 | ||||
How long did it usually take for you to fall asleep during the past 4 weeks? | MOS-SS 1 | .659 | ||||
Final awakening earlier than desired | AIS 3 | .606 | ||||
Total sleep duration | AIS 4 | .563 | ||||
During the past month, how often have you had trouble sleeping because you feel too hot | PSQI 5 (g) | .794 | ||||
During the past month, how often have you hadtrouble sleeping because you feel too cold | PSQI 5 (f) | .772 | ||||
During the past month, how often have you had trouble sleeping because you have pain | PSQI 5 (i) | .742 | ||||
Take naps (5 min or longer) during the day? | MOS-SS 11 | .788 | ||||
Snore during your sleep? | MOS-SS 10 | .611 | ||||
Functioning (physical and mental) during the day | AIS 8 | .479 | ||||
On the average, how many hours did you sleep each night during the past 4 weeks? | MOS-SS 2 | .739 | ||||
Get enough sleep to feel rested upon waking in the morning? | MOS-SS 4 | .698 | ||||
Cronbach alpha | 0.788 | 0.754 | 0.718 | 0.794 | 0.694 | |
Percentage of variances explained | 28.80 | 10.30 | 7.72 | 6.86 | 5.95 |
Confirmatory analysis
Bivariate analysis
LIS-18 | RIS | AIS | ISI | MOS-SS | ||
---|---|---|---|---|---|---|
Stress | Correlation coefficient r | 0.543 | 0.559 | 0.500 | 0.535 | −0.450 |
p-value | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | |
Depression | Correlation coefficient r | 0.580 | 0.560 | 0.566 | 0.530 | −0.334 |
p-value | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | |
Anxiety | Correlation coefficient r | 0.595 | 0.621 | 0.518 | 0.592 | −0.436 |
p-value | < 0.001 | < 0.001 | < 0.001 | < 0.001 | < 0.001 | |
Physical quality of life | Correlation coefficient r | 0.017 | 0.005 | 0.017 | −0.028 | − 0.009 |
p-value | 0.633 | 0.887 | 0.650 | 0.447 | 0.808 | |
Mental quality of life | Correlation coefficient r | −0.104 | −0.085 | −0.046 | − 0.053 | 0.150 |
p-value | 0.004 | 0.020 | 0.213 | 0.150 | < 0.001 |
Intraclass correlation coefficient (ICC) between insomnia scales
RIS | AIS | ISI | MOS-SS | ||
---|---|---|---|---|---|
RIS | ICC (CI) | N/A | 0.750 (0.711–0.783) | 0.875 (0.856–0.892) | −3.378 (−4.050--2.796) |
p-value | < 0.001 | < 0.001 | 1.000 | ||
AIS | ICC (CI) | 0.750 (0.711–0.783) | N/A | 0.767 (0.731–0.798) | −0.978 (−1.282--0.715) |
p-value | < 0.001 | < 0.001 | 1.000 | ||
ISI | ICC (CI) | 0.875 (0.856–0.892) | 0.767 (0.731–0.798) | N/A | −2.406 (−2.929--1.953) |
p-value | < 0.001 | < 0.001 | 1.000 | ||
MOS-SS | ICC (CI) | −3.378 (−4.050- -2.796) | −0.978 (−1.282- -0.715) | −2.406 (− 2.929--1.953) | N/A |
p-value | 1.000 | 1.000 | 1.000 |