Table 1. Characteristics of the study subjects (n = 4835).
| Variable | ||
| mean | SD | |
| Age (years) | 48.3 | 7.2 |
| Body mass index | 23.0 | 2.8 |
| Energy (kcal/day) | 1734 | 536 |
| Carbohydrate (g/day) | 242 | 88 |
| Protein (g/day) | 58 | 18 |
| Fat (g/day) | 42 | 14 |
| n | % | |
| Male/female | 3934/901 | |
| Insomnia | ||
| DIS | 621 | 12.8 |
| DMS | 980 | 20.3 |
| PQS | 1567 | 32.4 |
| Mental well-being | ||
| Yes, very much | 182 | 3.8 |
| Yes | 1405 | 29.0 |
| So-so | 2656 | 55.0 |
| Not sure | 592 | 12.2 |
| Perceived stress | ||
| Very much | 507 | 10.5 |
| Much | 1892 | 39.1 |
| Ordinary | 2170 | 44.9 |
| Little | 266 | 5.5 |
| Smoking status | ||
| Current | 1412 | 29.2 |
| Former | 1155 | 23.9 |
| Never | 2268 | 46.9 |
| Alcohol consumption (g/day) | ||
| 0 | 1470 | 30.4 |
| 1–20 | 1739 | 36.0 |
| 21–40 | 763 | 15.8 |
| 41–60 | 491 | 10.2 |
| >60 | 372 | 7.7 |
| Coffee drinking habit | ||
| Daily | 3439 | 71.1 |
| Regular exercisea | 2727 | 56.4 |
| Medical history | ||
| Cardiovascular disease | 35 | 0.7 |
| Diabetes mellitus | 370 | 7.7 |
| Hyperlipidemia | 158 | 3.3 |
| Hypertension | 809 | 16.7 |
DIS, difficulty initiating sleep; DMS, difficulty maintaining sleep; PQS, poor quality of sleep.
a≥60 min exercise at least once a month.