Table 4.
Multiple linear regression analysis for sleep quality with related factors.
| Variables | B | 95% CI | T | p |
|---|---|---|---|---|
| Coffee a | 0.726 | [−0.016, 1.467] | 1.923 | 0.055 |
| Alcohol b | 0.058 | [−0.529, 0.646] | 0.196 | 0.845 |
| Exercise c | −0.311 | [−0.879, 0.256] | −1.079 | 0.281 |
| EDs_place d | −0.381 | [−0.963, 0.201] | −1.289 | 0.198 |
| Depression e | 0.095 | [0.064, 0.127] | 6.025 | 0.000 |
| EDs_duration f | ||||
| EDs_duration_less than 30 min | 1.575 | [−0.422, 3.573] | 1.551 | 0.122 |
| EDs_duration_30 min_2 h | 2.588 | [0.667, 4.510] | 2.649 | 0.008 |
| EDs_duration_more 2 h | 3.343 | [1.383, 5.304] | 3.353 | 0.001 |
R2 = 0.207, F = 11.746, p = 0.000. Abbreviations: EDs = electronic devices. a Coffee: reference group = no coffee. b Alcohol: reference group = no alcohol. c Exercise: reference group = no exercise. d EDs_place: reference group = EDs kept close to the bed (under the pillow/in the bed); 1, EDs kept far from the bed (in the bedroom but at least 5 m from the bed). e Depression was measured using the CES-D. f EDs_duration: EDs usage duration variable, reference group = no use; 1 = less than 30 min; 2 = 30 min to 2 h; and 3 = more than 2 h; these variables were classified into dummy variables for analysis.