Baseline participants’ characteristics
| Variables | Total (n=352) | Male (n=174) | Female (n=178) |
| Demographics | |||
| Age (years) | 30.6 (SD=7.52) | 30.6 years (SD=7.01) | 30.6 (SD=8.04) |
| Social life, no. (%) | |||
| Single | 180 (51.1) | 80 (46.0) | 100 (56.1) |
| Married | 172 (48.9) | 94 (54.0) | 78 (43.8) |
| Health professionals, no. (%) | |||
| Physician | 131 (37.2) | 93 (53.4) | 38 (21.3) |
| Nurse | 134 (38.1) | 27 (15.5) | 107 (60.1) |
| Applied healthcare | 87 (24.7) | 54 (31.0) | 33 (18.5) |
| Modality of work, no. (%) | |||
| Day shift work | 80 (22.7) | 37 (21.2) | 43 (24.2) |
| Night shift work | 272 (77.3) | 137 (78,8) | 135 (75.8) |
| Period of night shift work, no. (%) | |||
| <2 years | 77 (21.8) | 48 (27.6) | 29 (16.2) |
| 2–5 years | 71 (20.1) | 43 (24.7) | 28 (15.7) |
| >5 years | 126 (35.8) | 48 (27.6) | 78 (43.8) |
| Length of working hours, no. (%) | |||
| 8 hours | 94 (26.7) | 50 (28.7) | 44 (24.7) |
| 12 hours | 188 (53.4) | 77 (44.2) | 111 (31.5) |
| 24 hours | 38 (10.7) | 29 (16.6) | 9 (5.0) |
| Others | 30 (8.5) | 17 (9.7) | 13 (7.3) |
| Sleeping hours, no. (%) | |||
| <6 hours | 149 (42.3) | 78 (44.8) | 71 (40.0) |
| 6–8 hours | 183 (52.0) | 89 (51.1) | 94 (52.8) |
| >8 hours | 16 (4.5) | 6 (3.4) | 10 (5.6) |