Table 1. Baseline characteristics of workers according to the chronotype.
| Variables | Total | Chronotype | p-valuea | |||
|---|---|---|---|---|---|---|
| Morningness | Intermediate | Eveningness | ||||
| Overall | 3,917 | 70 (1.8) | 3,661 (93.5) | 186 (4.7) | ||
| Sex | 0.525 | |||||
| Male | 2,088 (53.3) | 41 (58.6) | 1,956 (53.4) | 91 (48.9) | ||
| Female | 1,829 (46.7) | 29 (41.4) | 1,705 (46.6) | 95 (51.1) | ||
| Age (years) | < 0.001 | |||||
| 20–29 | 751 (19.2) | 4 (5.7) | 661 (18.1) | 86 (46.2) | ||
| 30–39 | 791 (20.2) | 2 (2.9) | 732 (20.0) | 57 (30.6) | ||
| 40–49 | 956 (24.4) | 18 (25.7) | 909 (24.8) | 29 (15.6) | ||
| 50–59 | 956 (24.4) | 18 (25.7) | 927 (25.3) | 11 (5.9) | ||
| ≥ 60 | 463 (11.8) | 28 (40.0) | 432 (11.0) | 3 (1.6) | ||
| Education | 0.540 | |||||
| Middle school or less | 14 (0.4) | 0 (0) | 13 (0.4) | 1 (0.5) | ||
| High school | 521 (13.3) | 15 (21.4) | 485 (13.2) | 21 (11.3) | ||
| College or more | 3,382 (86.3) | 55 (78.6) | 3,163 (86.4) | 164 (88.2) | ||
| Marital status | < 0.001 | |||||
| Unmarried & divorced | 1,720 (43.9) | 17 (24.3) | 1,568 (42.8) | 135 (72.6) | ||
| Married | 2,197 (56.1) | 53 (75.7) | 2,093 (57.2) | 51 (27.4) | ||
| Cohabitation status | < 0.001 | |||||
| Not living alone | 3,202 (81.7) | 65 (92.9) | 3,003 (82.0) | 134 (72.0) | ||
| Living alone | 715 (18.3) | 5 (7.1) | 658 (18.0) | 52 (28.0) | ||
| Smoking status | < 0.001 | |||||
| Current | 871 (22.2) | 18 (25.7) | 791 (21.6) | 62 (33.3) | ||
| Ex-smoker | 828 (21.1) | 21 (30.0) | 786 (21.5) | 21 (11.3) | ||
| None | 2,218 (56.6) | 31 (44.3) | 2,084 (56.9) | 103 (55.4) | ||
| Coffee consumption | 0.489 | |||||
| ≤ 3 times/week | 1,154 (29.5) | 26 (37.1) | 1,066 (29.1) | 62 (33.3) | ||
| Near-daily | 1,229 (31.4) | 18 (25.7) | 1,163 (31.8) | 48 (25.8) | ||
| 2–3 times/day | 1,534 (39.2) | 26 (37.1) | 1,432 (39.1) | 76 (40.9) | ||
| Alcohol (five-shot) | 0.440 | |||||
| None to moderate (< 2) | 1,816 (46.4) | 39 (55.7) | 1,694 (46.3) | 83 (44.6) | ||
| Risky | 2,101 (53.6) | 31 (44.3) | 1,967 (53.7) | 103 (55.4) | ||
| Income level | 0.608 | |||||
| Very sufficient | 68 (1.7) | 2 (2.9) | 62 (1.7) | 4 (2.2) | ||
| Sufficient | 741 (18.9) | 22 (31.4) | 685 (18.7) | 34 (18.3) | ||
| Enough | 1,067 (27.2) | 19 (27.1) | 1,000 (27.3) | 48 (25.8) | ||
| Not enough | 1,309 (33.4) | 16 (22.9) | 1,229 (33.6) | 64 (34.4) | ||
| Hard | 588 (15.0) | 8 (11.4) | 555 (15.2) | 25 (13.4) | ||
| Very hard | 144 (3.7) | 3 (4.3) | 130 (3.6) | 11 (5.9) | ||
| GPAQ | 0.027 | |||||
| High | 281 (7.2) | 10 (14.3) | 266 (7.3) | 5 (2.7) | ||
| Intermediate | 178 (4.5) | 5 (7.1) | 168 (4.6) | 5 (2.7) | ||
| Low | 3,458 (88.3) | 55 (78.6) | 3,227 (88.1) | 176 (94.6) | ||
| Job category | 0.123 | |||||
| Blue collar | 678 (17.3) | 14 (20.0) | 640 (17.5) | 24 (12.9) | ||
| White collar | 2,833 (72.3) | 44 (62.9) | 2,640 (72.1) | 149 (80.1) | ||
| Pink collar | 406 (10.4) | 12 (17.1) | 381 (10.4) | 13 (7.0) | ||
| Job tenure | 0.237 | |||||
| ≥ 3 years | 3,597 (91.8) | 60 (85.7) | 3,369 (92.0) | 168 (90.3) | ||
| < 3 years | 320 (8.2) | 10 (14.3) | 292 (8.0) | 18 (9.7) | ||
| Employment status | 0.991 | |||||
| Full time work | 3,726 (95.1) | 66 (94.3) | 3,483 (95.1) | 177 (95.2) | ||
| Part time work | 191 (4.9) | 4 (5.7) | 178 (4.9) | 9 (4.8) | ||
| Multiple job holdings | 0.204 | |||||
| None | 3,258 (83.2) | 55 (78.6) | 3,059 (83.6) | 144 (77.4) | ||
| Same field | 273 (7.0) | 8 (11.4) | 251 (6.9) | 14 (7.5) | ||
| Different field | 386 (9.9) | 7 (10.0) | 351 (9.6) | 28 (15.1) | ||
| Working hour | 0.818 | |||||
| ≤ 30 | 654 (16.7) | 9 (12.9) | 607 (16.6) | 38 (20.4) | ||
| 31–40 | 1,959 (50.0) | 40 (57.1) | 1,834 (50.1) | 85 (45.7) | ||
| 41–52 | 1,104 (28.2) | 16 (22.9) | 1,036 (28.3) | 52 (28.0) | ||
| > 52 | 200 (5.1) | 5 (7.1) | 184 (5.0) | 11 (5.9) | ||
| Depression (PHQ-9 ≥ 5) | < 0.001 | |||||
| No | 2,242 (57.2) | 52 (74.3) | 2,127 (58.1) | 63 (33.9) | ||
| Yes | 1,675 (42.8) | 18 (25.7) | 1,534 (41.9) | 123 (66.1) | ||
Values are presented as number of participants (%).
Total GPAQ are counted as the sum of the total MET minutes of activities at work, moving from one place to another, leisure activities.
GPAQ = Global Physical Activity Questionnaire; PHQ-9: Patient Health Questionnaire-9.
aThe results were obtained by χ2 test.