Table 2.
Prevalence and adjusted OR (95% CI) of depressive symptoms by groups of napping frequency and duration, and Pittsburgh Sleep Quality Index components and global sleep quality
| Variables | Depressive symptoms (%) | Model 1 | Model 2 | Model 3 |
|---|---|---|---|---|
| Napping frequency | ||||
| Non-nappers | 6699 (4.6) | 1.00 | 1.00 | 1.00 |
| 1–3 days/week | 2306 (4.8) | 1.13 (0.90, 1.41) | 1.11 (0.89, 1.40) | 1.11 (0.88, 1.40) |
| 4–6 days/week | 1500 (4.6) | 1.14 (0.87, 1.50) | 1.12 (0.85, 1.47) | 1.10 (0.83, 1.45) |
| daily | 6281 (6.4) | 1.41 (1.20, 1.65)*** | 1.38 (1.18, 1.62)*** | 1.38 (1.17, 1.62)*** |
| P for trend | < 0.001 | < 0.001 | < 0.001 | |
| Napping duration | ||||
| Non-nappers | 6699 (4.6) | 1.00 | 1.00 | 1.00 |
| < 60 min | 3311 (5.4) | 1.24 (1.02, 1.51)* | 1.23 (1.01, 1.49)* | 1.22 (1.01, 1.49)* |
| 60–90 min | 5561 (5.5) | 1.26 (1.08, 1.49)** | 1.23 (1.04, 1.46)* | 1.24 (1.03, 1.45)* |
| > 90 min | 1093 (8.0) | 1.72 (1.33, 2.21)*** | 1.67 (1.30, 2.16)*** | 1.68 (1.30, 2.18)*** |
| P for trend | < 0.001 | < 0.001 | < 0.001 | |
| Subjective sleep quality | ||||
| Good | 14,213 (4.1) | 1.00 | 1.00 | 1.00 |
| Poor | 2575(12.2) | 3.02 (2.60, 3.50)*** | 2.97 (2.55, 2.45)*** | 2.98 (2,57, 3.47)*** |
| P | < 0.001 | < 0.001 | < 0.001 | |
| Sleep latency | ||||
| ≤30 min | 14,544 (4.5) | 1.00 | 1.00 | 1.00 |
| 31–60 min | 1670 (8.6) | 1.74 (1.43, 2.11)*** | 1.71 (1.41, 2.08)*** | 1.70 (1.40, 2.06)*** |
| > 60 min | 574 (14.6) | 3.03 (2.35, 3.90)*** | 3.02 (2.34, 3.89)*** | 3.01 (2.33, 3.88)*** |
| P for trend | < 0.001 | < 0.001 | < 0.001 | |
| Sleep duration | ||||
| < 5 h/day | 893 (11.0) | 2.32 (1.81, 2.97)*** | 2.28 (1.78, 2.92)*** | 2.31 (1.80, 2.96)*** |
| 5–6 h/day | 6503 (6.7) | 1.58 (1.36, 1.84)*** | 1.59 (1.36, 1.85)*** | 1.59 (1.36, 1.85)*** |
| 7–8 h/day | 7917 (4.0) | 1.00 | 1.00 | 1.00 |
| > 8 h/day | 843 (2.7) | 0.67 (0.43, 1.03) | 0.66 (0.43, 1.03) | 0.67 (0.44, 1.04) |
| P for trend | < 0.001 | < 0.001 | < 0.001 | |
| Sleep efficiency | ||||
| ≥85% | 11,348 (4.1) | 1.00 | 1.00 | 1.00 |
| 75–84% | 2664 (6.9) | 1.54 (1.29, 1.85)*** | 1.54 (1.29, 1.85)*** | 1.54 (1.28, 1.85)*** |
| 65–74% | 1403 (8.3) | 1.88 (1.51, 2.34)*** | 1.85 (1.49, 2.29)*** | 1.86 (1.50, 2.31)*** |
| < 65% | 1373 (9.3) | 1.98 (1.60, 2.45)*** | 1.94 (1.57, 2.40)*** | 1.94 (1.57, 2.39)*** |
| P for trend | < 0.001 | < 0.001 | < 0.001 | |
| Sleep disturbances | ||||
| Not at all/<once per week | 16,416 (4.7) | 1.00 | 1.00 | 1.00 |
| At least once per week | 372 (29.8) | 6.51 (5.08, 8.34)*** | 6.41 (5.00, 8.21)*** | 6.35 (4.95, 8.14)*** |
| P | < 0.001 | < 0.001 | < 0.001 | |
| Sleep medications | ||||
| Not at all/<once per week | 16,415 (5.1) | 1.00 | 1.00 | 1.00 |
| At least once per week | 373 (13.4) | 2.99 (2.18, 4.12)*** | 2.88 (2.09, 3.96)*** | 2.91 (2.12, 4.01)*** |
| P | < 0.001 | < 0.001 | < 0.001 | |
| Daytime dysfunction | ||||
| Not at all/<once per week | 15,576 (3.9) | 1.00 | 1.00 | 1.00 |
| At least once per week | 1212 (23.5) | 6.53 (5.55, 7.68)*** | 6.47 (5.50, 7.61)*** | 6.42 (5.46, 7.56)*** |
| P | < 0.001 | < 0.001 | < 0.001 | |
| Global sleep quality | ||||
| Good (PSQI< 6) | 11,432 (2.8) | 1.00 | 1.00 | 1.00 |
| Poor (PSQI≥6) | 5356 (10.7) | 3.60 (3.12, 4.17)*** | 3.56 (3.08, 4.12)*** | 3.56 (3,07, 4.11)*** |
| P | < 0.001 | < 0.001 | < 0.001 | |
Model 1: adjusting for sex, age, education level, occupation, personal income, smoking status, alcohol consumption, physical activity, support from family members, and contacts with relatives and friends;
Model 2: additionally adjusting for BMI, presence of chronic diseases, and self-rated health;
Model 3: additionally adjusting for daytime napping or nighttime sleep quality
* P < 0.05, *** P < 0.001