Table 1. Characteristics of the sample by shift work schedule.
| Variables | Daytime (n=907) | Three-shift rotation (n=538) | Two-shift rotation (n=645) | p-valuea | |
|---|---|---|---|---|---|
| Sex | <0.001*** | ||||
| Male | 775 (85.4) | 495 (92.0) | 602 (93.3) | ||
| Female | 132 (14.6) | 43 (8.0) | 43 (6.7) | ||
| Age (years) | <0.001*** | ||||
| 25–34 | 96 (10.6) | 28 (5.2) | 38 (5.9) | ||
| 35–44 | 399 (44.0) | 187 (34.8) | 334 (51.8) | ||
| 45–54 | 292 (32.2) | 257 (47.8) | 212 (32.9) | ||
| 55–64 | 120 (13.2) | 66 (12.3) | 61 (9.5) | ||
| Smoking status | <0.001*** | ||||
| Non-smoker | 605 (66.7) | 334 (62.1) | 352 (54.6) | ||
| Current smoker | 302 (33.3) | 204 (37.9) | 293 (45.4) | ||
| Alcohol consumption | 0.015* | ||||
| None | 283 (31.2) | 189 (35.1) | 174 (27.0) | ||
| Low-risk drinking | 207 (22.8) | 98 (18.2) | 139 (21.6) | ||
| High-risk drinking | 417 (46.0) | 251 (46.7) | 332 (51.5) | ||
| Physical activity | 0.360 | ||||
| Sufficient | 427 (47.1) | 271 (50.4) | 300 (46.5) | ||
| Insufficient | 480 (52.9) | 267 (49.6) | 345 (53.5) | ||
| Workplace size | <0.001*** | ||||
| Medium(50–299 workers) | 321 (35.4) | 141 (26.2) | 278 (43.1) | ||
| Large (≥300 workers) | 586 (64.6) | 397 (73.8) | 367 (56.9) | ||
| Type of job | <0.001*** | ||||
| White-collar | 539 (59.4) | ?50? (9.3)50 (9.3) | 30 (4.7) | ||
| Blue-collar | 368 (40.6) | 488 (90.7) | 615 (95.3) | ||
| Metabolic syndrome | 0.009** | ||||
| Yes | 93 (10.3) | 59 (11.0) | 98 (15.2) | ||
| No | 814 (89.7) | 479 (89.0) | 547 (84.8) | ||
| Sleep disturbancec | 0.170 | ||||
| No | 317 (58.9) | 355 (55.0) | |||
| Subthreshold insomnia | 170 (31.7) | 208 (32.2) | |||
| Clinical insomnia | 51 (9.5) | 82 (12.7) | |||
| Years of rotating night shifts (year)bc | 15.8 ± 6.3 | 13.5 ± 5.9 | 0.02* | ||
| Frequency of night shift workbc | 8.3 ± 0.7 | 10.3 ± 1.7 | <0.001*** | ||
Values for categorical variables given as number (percentage); Values for continuous variables given as mean ± SD.
*p<0.05, **p<0.01, ***p<0.001.
a χ2 test, categorical variables; t-test, continuous variables.
b Continuous variables.
c Variables for rotating night shift workers.