Table 1.
Demographic and psychosocial characteristics of the study subjects
| Variables | Category | Control n = 8855 |
Insomnia n = 883 |
|---|---|---|---|
| Age, years* | < 40 | 4838 (54.6) | 428 (48.5) |
| 40–49 | 2585 (29.2) | 273 (30.9) | |
| ≥ 50 | 1432 (16.2) | 182 (20.6) | |
| Sex* | Male | 8273 (93.4) | 807 (91.4) |
| Female | 582 (6.6) | 76 (8.6) | |
| Body mass index, kg/m2 | < 25 | 5628 (63.6) | 574 (65.0) |
| ≥ 25 | 3227 (36.4) | 309 (35.0) | |
| Education, years | High school | 1770 (20.0) | 174 (19.7) |
| College | 2886 (32.6) | 269 (30.5) | |
| University | 4042 (45.6) | 414 (46.9) | |
| Graduate school | 157 (1.8) | 26 (2.9) | |
| Income, × 1000 KRW/month* | < 3000 | 3226 (36.4) | 266 (30.1) |
| 3000–4999 | 4291 (48.5) | 460 (52.1) | |
| ≥ 5000 | 1338 (15.1) | 157 (17.8) | |
| Marital status* | Married | 6178 (69.8) | 652 (73.8) |
| Unmarried | 2551 (28.8) | 208 (23.6) | |
| Divorced or bereaved | 126 (1.4) | 23 (2.6) | |
| Smoking* | Never or ex-smoker | 6313 (71.3) | 663 (75.1) |
| Current smoker | 2542 (28.7) | 220 (24.9) | |
| Alcohol consumption* | None or social | 6099 (68.9) | 576 (65.2) |
| Moderate or heavya | 2756 (31.1) | 307 (34.7) | |
| Caffeine intake, cups/day*b | < 1 | 1496 (16.9) | 182 (20.6) |
| 1–2 | 4377 (49.4) | 385 (43.6) | |
| ≥ 3 | 2982 (33.7) | 316 (35.8) | |
| Exercise, times/week | 0–1 | 3256 (36.8) | 351 (39.8) |
| 2–3 | 3339 (37.7) | 309 (35.0) | |
| ≥ 4 | 2260 (25.5) | 223 (25.2) | |
| Fatigue* | No | 5685 (64.2) | 162 (18.3) |
| Yes | 3170 (35.8) | 721 (81.7) | |
| Depression* | No | 8697 (98.2) | 663 (75.1) |
| Yes | 158 (1.8) | 220 (24.9) | |
| Anxiety* | No | 8744 (99.0) | 705 (82.4) |
| Yes | 92 (1.0) | 151 (17.6) | |
| Post-traumatic stress disorder* | No | 8222 (92.9) | 563 (63.8) |
| Yes | 633 (7.1) | 320 (36.2) |
The data are presented as number (%)
*p < 0.05
aMore than seven cups of Soju per week
bFrequency of coffee or tea intake