Table 4.
Total, direct, and indirect effects (unstandardized estimates) of the mediation models examining the association between negative affect (anxiety, depression, and stress) and physical and mental health-related quality of life with sleep quality as mediator.
| Estimate (SE) | t a | 95% CI b | |
|---|---|---|---|
| Total effect | |||
| DASS-21 anxiety → PCS | −0.57 (0.09) | −6.17 *** | [−0.75, −0.39] |
| DASS-21 depression → PCS | −0.13 (0.08) | −1.52 | [−0.30, 0.04] |
| DASS-21 stress → PCS | 0.13 (0.10) | 1.27 | [−0.07, 0.33] |
| DASS-21 anxiety → MCS | 0.13 (0.11) | 1.12 | [−0.09, 0.35] |
| DASS-21 depression → MCS | −0.70 (0.10) | −7.34 *** | [−0.96, −0.55] |
| DASS-21 stress → MCS | −0.64 (0.12) | −5.18 *** | [−0.88, −0.40] |
| Direct effect | |||
| DASS-21 anxiety → PCS | −0.52 (0.09) | −5.63 *** | [−0.70, −0.34] |
| DASS-21 depression → PCS | −0.09 (0.08) | −1.10 | [−0.26, 0.07] |
| DASS-21 stress → PCS | 0.18 (0.10) | 1.75 | [−0.02, 0.38] |
| DASS-21 anxiety → MCS | 0.17 (0.11) | 1.50 | [−0.05, 0.39] |
| DASS-21 depression → MCS | −0.72 (0.10) | −7.01 *** | [−0.93, −0.52] |
| DASS-21 stress → MCS | −0.60 (0.12) | −4.80 *** | [−0.84, −0.35] |
| Indirect effect | |||
| DASS-21 anxiety → PSQI → PCS | −0.05 (0.02) | [−0.10, −0.01] | |
| DASS-21 depression → PSQI → PCS | −0.04 (0.02) | [−0.08, −0.003] | |
| DASS-21 stress → PSQI → PCS | −0.05 (0.02) | [−0.10, −0.01] | |
| DASS-21 anxiety → PSQI → MCS | −0.04 (0.02) | [−0.10, −0.01] | |
| DASS-21 depression → PSQI → MCS | −0.03 (0.02) | [−0.07, −0.001] | |
| DASS-21 stress → PSQI → MCS | −0.04 (0.02) | [−0.10, −0.004] |
Note. PSQI: Pittsburgh Sleep Quality Index; DASS-21: 21-item Depression Anxiety Stress Scale; PCS: Short Form-12 Physical Component Summary; MCS: Short Form-12 Mental Component Summary. *** p < 0.001. a: t statistics and relative p-values were computed only for total effects and direct effects. b: 95% percentile bootstrap confidence intervals are reported for indirect effects.