Table 1.
Baseline characteristic of the participants according to trajectories of sleep quality
| Sleep quality patterns determined by PSQI scores | P | |||||
|---|---|---|---|---|---|---|
| Normal-stable (n = 1697) | Moderate-stable (n = 1157) | Poor-stable (n = 320) | Developing to poor (n = 84) | Severely poor- stable (n = 89) | ||
| Men, % | 984 (58.0) | 555 (48.0) | 111 (34.7) | 21 (25.0) | 30 (33.7) | <0.001 |
| Age, years | 47.94 ± 7.11 | 49.09 ± 7.38 | 50.04 ± 7.77 | 49.64 ± 7.24 | 49.44 ± 8.05 | <0.001 |
| Education, % | ||||||
| Lower: high school, or less | 1295 (76.4) | 891 (77.0) | 275 (85.9) | 77 (91.7) | 79 (89.8) | <0.001 |
| Higher: college, or above | 400 (23.6) | 266 (23.0) | 45 (14.1) | 7 (8.3) | 9 (10.2) | |
| Monthly household income, % | ||||||
| <$2500 | 1144 (67.8) | 799 (69.6) | 238 (75.1) | 67 (79.8) | 71 (79.8) | 0.004 |
| ≥$2500 | 544 (32.2) | 349 (30.4) | 79 (24.9) | 17 (20.2) | 18 (20.2) | |
| Occupation, % | ||||||
| Unemployment (homemaker, etc.) | 840 (49.6) | 659 (57.1) | 227 (71.4) | 57 (67.9) | 58 (65.2) | <0.001 |
| Manual labor | 590 (34.8) | 343 (29.7) | 64 (20.1) | 22 (26.2) | 25 (28.1) | |
| Professional labor | 265 (15.6) | 152 (13.2) | 27 (8.5) | 5 (6.0) | 6 (6.7) | |
| Currently married, % | 1622 (95.6) | 1082 (93.5) | 289 (90.3) | 81 (96.4) | 83 (93.3) | 0.011 |
| Currently smoking, % | 419 (24.8) | 222 (19.1) | 65 (20.4) | 11 (13.3) | 17 (19.1) | <0.001 |
| Currently drinking, % | 910 (53.7) | 604 (52.2) | 148 (46.3) | 36 (42.9) | 38 (42.7) | 0.013 |
| Moderate exercise, % | 648 (38.6) | 448 (39.4) | 134 (42.1) | 26 (32.5) | 38 (43.2) | 0.481 |
| Disease diagnosis*, % | 326 (19.2) | 253 (21.8) | 75 (23.1) | 21 (25.0) | 20 (22.5) | 0.234 |
| Sleep drug intake†, % | 42 (2.5) | 63 (5.5) | 44 (13.8) | 15 (18.3) | 31 (34.8) | <0.001 |
| Sleep duration, hour | 6.9 ± 1.12 | 6.52 ± 1.22 | 6.14 ± 1.28 | 6.22 ± 1.63 | 6.18 ± 1.55 | <0.001 |
| BDI‡ | 5 [2-9] | 7 [4-12] | 9.5 [6-15] | 10 [7-16] | 14 [7-20] | <0.001 |
| BMI, kg/m2 | 24.67 ± 2.83 | 24.81 ± 2.89 | 24.65 ± 2.97 | 24.48 ± 2.92 | 24.69 ± 2.69 | 0.676 |
| Total cholesterol, mg/dL | 196.12 ± 35.3 | 196.69 ± 35.7 | 195.74 ± 33.56 | 193.74 ± 32.7 | 192.78 ± 34.89 | 0.821 |
| HDL cholesterol, mg/dL | 44.36 ± 9.52 | 44.84 ± 10.01 | 45.28 ± 9.59 | 45.61 ± 9.98 | 46.15 ± 9.48 | 0.187 |
| LDL cholesterol, mg/dL | 121.27 ± 31.43 | 121.28 ± 30.82 | 120.21 ± 30.96 | 117.04 ± 29.15 | 120.51 ± 32.49 | 0.777 |
| SBP, mmHg | 116.34 ± 16.12 | 116.63 ± 16.85 | 116.47 ± 17.73 | 117.39 ± 17.62 | 114.01 ± 16.48 | 0.665 |
| DBP, mmHg | 78.27 ± 11.19 | 77.91 ± 11.05 | 77.12 ± 11.64 | 77.86 ± 12.26 | 76.45 ± 11.65 | 0.320 |
| Triglyceride, mg/dL | 132 [97-186] | 134 [97-186] | 140 [97-187] | 138 [100-189] | 121 [89-158] | 0.173 |
| HbA1c, % | 5.5 [5.3-5.8] | 5.6 [5.3-5.8] | 5.5 [5.3-5.8] | 5.5 [5.3-5.8] | 5.5 [5.3-5.9] | 0.631 |
| Fasting insulin, uIU/mL | 6.8 [5.0-9.1] | 6.9 [5.1-9.2] | 6.6 [4.7-9.0] | 7.1 [5.0-9.6] | 6.5 [5.0-8.8] | 0.437 |
| Fasting glucose, mg/dL | 83 [78-91] | 83 [78-92] | 82 [77-88] | 83.5 [77-90] | 82 [76-90] | 0.226 |
| High-sensitivity C-reactive protein | 0.14 [0.07-0.23] | 0.13 [0.06-0.23] | 0.14 [0.06-0.25] | 0.15 [0.06-0.23] | 0.09 [0.04-0.18] | 0.099 |
Abbreviations: BMI, body mass index; HDL, high-density lipoprotein; LDL, low-density lipoprotein; SBP, systolic blood pressure; DBP, diastolic blood pressure; HbA1c, hemoglobin A1c.
*Including cardiovascular disease (coronary artery, myocardial infarction, and cerebrovascular diseases), hypertension, diabetes, dyslipidemia, and cancer.
†Including past and current users.
‡Assessed at years 4.