Psychometric Analysis Of The Sleep Hygiene Index And Correlation With Stress And Anxiety Among Saudi University Students

Figures & data

Table 1 Participant Characteristics Of Saudi University Students

Characteristics	Mean±SD/Frequency (%)
Age (year)	20.49±1.94
BMI (kg/m^2)	22.86±10.50
Years of University education
1–3	57 (27.9)
4–5	75 (36.8)
6–7	13 (6.4)
Did not report	59 (28.9)
Courses
Biomedical and dental technology	6 (2.9)
Radiology	17 (8.3)
Health and physical education	8 (3.9)
Nursing and allied healthcare (Physio/Occupational/Speech-therapy)	81 (39.7)
Clinical laboratory sciences and technology	20 (9.8)
Others (Comprised of Biology, Biophysics, Engineering, etc.)	20 (9.8)
Did not report	52 (25.5)
PSS	16.2±6.0
SHI	6.6±2.3
GAD-7 scale	5.3±4.4
Self-reported sleep
Normal	147 (72.1)
Disturbed	36 (17.6)
Did not report	21 (10.3)
Academic difficulties
None	67 (32.8)
Some	119 (58.3)
Very much	18 (8.8)

Abbreviations: SD, standard deviation; BMI, body mass index; PSS, perceived stress scale; SHI, sleep hygiene index; GAD-7, generalized anxiety disorder-7.

Table 2 Internal Consistency And Univariate Distribution Characteristics Of The Sleep Hygiene Index (SHI) In Saudi University Students

Items Of The Sleep Hygiene Index (Description)	Skewness	Kurtosis	Item-Total Correlation	Cronbach’s Alpha If Item Deleted
SHI-1 (I take daytime naps lasting two or more hours)	−0.318	−1.889	0.48*	0.56
SHI-2 (I go to bed at different times from day to day)	−1.397	−0.053	0.48*	0.55
SHI-3 (I get out of bed at different times from day to day)	−0.994	−1.010	0.42*	0.57
SHI-4 (I exercise to the point of sweating within 1 hr of going to bed)	2.469	4.073	0.46*	0.61
SHI-5 (I stay in bed longer than I should two or three times a week)	0.030	−1.985	0.44*	0.56
SHI-6 (I use alcohol, tobacco, or caffeine within 4 hrs of going to bed or after going to bed)	0.708	−1.488	0.48*	0.55
SHI-7 (I do something that may wake me up before bedtime)	−2.535	4.421	0.31*	0.57
SHI-8 (I go to bed feeling stressed, angry, upset, or nervous)	0.419	−1.811	0.50*	0.55
SHI-9 (I use my bed for things other than sleeping or sex)	−1.098	−0.788	0.38*	0.57
SHI-10 (I sleep on an uncomfortable bed)	1.627	0.640	0.41*	0.56
SHI-11 (sleep in an uncomfortable bedroom)	2.230	2.979	0.35*	0.56
SHI-12 (I do important work before bedtime)	−0.139	−1.971	0.36*	0.58
SHI-13 (I think, plan, or worry when I am in bed)	−0.731	−1.458	0.46*	0.56

Note: *P<0.01.

Figure 1 (A) Parallel analysis based on principal component analysis of the Sleep hygiene index (SHI) in Saudi university students. (B) Parallel analysis based on minimum rank factor analysis of the Sleep hygiene index (SHI) in Saudi university students.

Table 3 Exploratory Factor Analysis: Eigenvalues And Total Variance Explained Of The Sleep Hygiene Index (SHI) In Saudi University Students

Factor	Eigenvalues	% Of Variance	Cumulative %
1	3.53	27.16	27.16
2	1.81	13.88	41.04
3	1.78	13.72	54.76
4	1.23	9.5	64.26
5	0.98	7.55	71.81
6	0.76	5.9
7	0.7	5.37
8	0.61	4.66
9	0.57	4.37
10	0.42	3.22
11	0.31	2.39
12	0.18	1.41
13	3.53	27.16

Note: Exploratory factor analysis for initial unrotated solution.

Table 4 Exploratory Factor Analysis: Factor Loadings And Communality Of The Sleep Hygiene Index (SHI) In Saudi University Students

Items Of The Sleep Hygiene Index (Description)	Factor Loadings				Communality
	Factor-1	Factor-2	Factor-3	Factor-4
SHI-1 (I take daytime naps lasting two or more hours)	−0.456				0.231
SHI-2 (I go to bed at different times from day to day)	−0.659				0.608
SHI-3 (I get out of bed at different times from day to day)	−0.351				0.229
SHI-4 (I exercise to the point of sweating within 1 hr of going to bed)			−0.596		0.444
SHI-5 (I stay in bed longer than I should two or three times a week)	−0.425				0.303
SHI-6 (I use alcohol, tobacco, or caffeine within 4 hrs of going to bed or after going to bed)	−0.465		−0.325	0.325	0.437
SHI-7 (I do something that may wake me up before bedtime)	−0.498		0.353		0.409
SHI-8 (I go to bed feeling stressed, angry, upset, or nervous)	−0.482			0.459	0.499
SHI-9 (I use my bed for things other than sleeping or sex)	−0.425		0.320		0.360
SHI-10 (I sleep on an uncomfortable bed)	−0.540			−0.356	0.505
SHI-11 (sleep in an uncomfortable bedroom)	−0.394		−0.537		0.594
SHI-12 (I do important work before bedtime)		0.873			0.862
SHI-13 (I think, plan, or worry when I am in bed)	−0.515	0.353			0.394

Note: Exploratory factor analysis for initial unrotated solution.

Table 5 Fit Statistics Of The Sleep Hygiene Index Models In Saudi University Students

Models	WRMR	GFI	CFI	RMSEA	χ^2#	df	p	χ^2/df
1-Factor	0.086	0.821	0.754	0.07 (0.05–0.08)	130.142	65	<0.01	2.01
2-Factor	0.07	0.856	0.856	0.06 (0.05–0.08)	92.065	53	<0.01	1.74
4-Factor	0.037	0.891	0.983	0.03 (0.01–0.05)	36.648	32	0.261	1.14

Note: ^#Robust Mean and Variance-Adjusted Chi Square.

Abbreviations: WRMR, weighted root mean square residual; GFI, goodness of fit index; CFI, comparative fit index; RMSEA, root mean square error of approximation.