Table 1.
General characteristics of study subjects (n = 901)
| Male (%) (n = 561) | Female (%) (n = 340) | p-value | |
|---|---|---|---|
| Age (years) | |||
| < 20 | 24 (4.3%) | 53 (15.6%) | < 0.001*§ |
| 21–25 | 5 (0.9%) | 115 (33.8%) | |
| 26–30 | 53 (9.4%) | 119 (35.0%) | |
| 31–35 | 317 (56.5%) | 45 (13.2%) | |
| 36–40 | 162 (28.9%) | 8 (2.4%) | |
| Body mass index | |||
| < 25 kg/m2 | 309 (55.1%) | 276 (81.2%) | < 0.001* |
| ≥ 25 kg/m2 | 252 (44.9%) | 64 (18.8%) | |
| Regular exercise (times / week) | |||
| 0 | 204 (36.4%) | 220 (64.7%) | < 0.001*§ |
| 1–2 | 239 (42.6%) | 89 (26.2%) | |
| ≥ 3 | 118 (21.0%) | 31 (9.1%) | |
| Smoking | |||
| Non-smoker | 196 (34.9%) | 285 (83.8%) | < 0.001*§ |
| Past smoker | 132 (23.5%) | 31 (9.1%) | |
| Current smoker | 233 (41.5%) | 24 (7.1%) | |
| Alcohol consumption (times / week) | |||
| 0 | 107 (19.1%) | 126 (37.1%) | < 0.001*§ |
| 1–2 | 333 (59.4%) | 179 (52.6%) | |
| ≥ 3 | 121 (21.6%) | 35 (10.3%) | |
| Duration of shift work (years) | |||
| < 5 | 44 (7.8%) | 79 (23.2%) | < 0.001*§ |
| 5–9 | 190 (33.9%) | 152 (44.7%) | |
| 10–14 | 267 (47.6%) | 101 (29.7%) | |
| ≥ 15 | 60 (10.7%) | 8 (2.4%) | |
| Weekly working hours (hours / week) | |||
| ≤ 40 | 83 (14.8%) | 36 (10.6%) | 0.491§ |
| 41–51 | 383 (68.3%) | 252 (74.1%) | |
| ≥ 52 | 95 (16.9%) | 52 (15.3%) | |
| ISI-K index (score) | |||
| Non-significant insomnia (0–15) | 530 (94.5%) | 312 (91.8%) | 0.111 |
| Clinically significant insomnia (16–28) | 31 (5.5%) | 28 (8.2%) | |
| Functional dyspepsia | |||
| (−) | 533 (95.0%) | 311 (91.5%) | 0.034* |
| (+) | 28 (5.0%) | 29 (8.5%) | |
ISI-K Korean version of insomnia severity index
§p-value of linear by linear association
*p < 0.05