Table 1.
Items and factor loadings of the Sleep Hygiene Index (SHI).
Fig 1.
Proposed multiple mediation model.
Chronotype and trait self-control were considered as independent variables (X1, X2), sleep hygiene habits (M1–Mn-1) and bedtime media use (Mn) as mediators and sleep quality as outcome variable (Y). X can affect Y either directly (c’) or indirectly through M1-Mn (a1-an, b1-bn paths). Age, gender, and marital status were included as covariates. N represents the number of mediators, and n-1 was determined by the number of sleep hygiene components derived from exploratory factor analysis of the item scores of Sleep Hygiene Index.
Table 2.
Descriptive statistics of the total sample and by circadian typology.
Fig 2.
Distributions of chronotype (rMEQ) and trait self-control in the total sample.
Table 3.
Frequency and duration of bedtime media use by media type.
Table 4.
Bivariate associations between study variables.
Table 5.
Summary of regression coefficients for the multiple mediation model.
Table 6.
Bootstrapping results of the total, direct and indirect effects of multiple mediation model.
Fig 3.
Pre-sleep stress management and sleep timing regularity as a function of chronotype and trait self-control.
The interactions were probed at high (1SD above the mean) and low levels (1SD below the mean) of chronotype and trait self-control.
Fig 4.
Sleep quality as a function of chronotype and levels of pre-sleep stress management.
The interactions were probed at high (1SD above the mean) and low levels (1SD below the mean) of chronotype and pre-sleep stress management.