| Gender | Male | 129 (86.6) | 31.48±8.88 | 2.89 (0.004) |
| Female | 20 (13.4) | 25.40±7.77 |
| Age (yr) | M±SD (range) | 29.51±8.02 (19-52) | | |
| < 30 | 86 (57.7) | 29.54±8.57 | 2.47 (0.087) |
| 30–39 | 41 (27.5) | 31.15±10.05 |
| ≥ 40 | 22 (14.8) | 34.18±7.59 |
| Educational level | ≤ Associate degree | 81 (54.5) | 29.84±8.87 | -1.23 (0.221) |
| Bachelor degree or higher | 68 (45.6) | 31.65±9.03 |
| Living arrangement | Living alone | 79 (53.0) | 30.28±9.44 | -0.56 (0.578) |
| Living with others | 70 (47.0) | 31.10±8.43 |
| Marital status | Without spouse | 102 (68.5) | 29.26±8.63 | -2.88 (0.005) |
| With spouse | 47 (31.5) | 33.70±9.01 |
| Rotating system | D-N-O | 14 (9.4) | 27.71±11.77 | 0.97 (0.410) |
| D-D-N-N-O-O | 113 (75.8) | 31.04±8.89 |
| D-N-O-O | 8 (5.4) | 27.88±4.49 |
| Fixed day shift | 14 (9.4) | 32.21±8.10 |
| Work experience (years) | M±SD (range) | 7.95±8.33 (0-31) | | |
| < 5 | 81 (54.4) | 29.79±9.09 | 1.37 (.254) |
| 5-9 | 18 (12.1) | 29.00±8.42 |
| 10-14 | 14 (9.4) | 31.86±8.22 |
| ≥ 15 | 36 (24.2) | 33.00±9.06 |
| Working department | Approach control | 76 (51.0) | 31.01±9.58 | 0.41 (0.664) |
| Local/ground control | 65 (43.6) | 30.58±8.66 |
| Ramp·area control | 8 (5.4) | 28.00±4.50 |
| Number of monthly night shifts | M±SD (range) | 8.73±3.14 (0-12) | | |
| 0 | 14 (9.4) | 30.79±6.72 | 0.15 (0.857) |
| 1-7 | 11 (7.4) | 32.09±9.06 |
| ≥ 8 | 124 (83.2) | 30.52±9.22 |
| Current disease | No | 126 (84.6) | 30.60±9.36 | -0.22 (.826) |
| Yes | 23 (15.4) | 31.04±6.54 |
| Current medication use | No | 131 (87.9) | 30.68±9.24 | 0.06 (0.956) |
| Yes | 18 (12.1) | 30.56±6.84 |
| Body Mass Index (BMI) (kg/m2) | M±SD (range) | 24.28±3.37 (18.36-40.35) | | |
| Underweight and normal weight (<23.0) | 55 (36.9) | 27.58±8.44 | 5.47 (0.005) |
| Overweight (23.0≤BMI<25.0) | 39 (26.2) | 32.51±9.10 |
| Obese (≥25) | 55 (36.9) | 32.44±8.67 |
| Smoking status | Non-smoker (never/former) | 109 (73.2) | 30.74±8.97 | 0.18 (0.861) |
| Current smoker | 40 (26.8) | 30.45±9.04 |
| Alcohol consumption frequency | ≤ 1 time/month | 53 (35.6) | 29.79±8.95 | 0.44 (0.643) |
| 2-4 times/month | 59 (39.6) | 31.39±9.57 |
| ≥ 2 times/week | 37 (24.8) | 30.76±8.06 |
| At-risk drinking | < 1 time/month | 59 (39.6) | 29.85±8.35 | -0.90 (0.369) |
| ≥ 1 time/month | 90 (60.4) | 31.20±9.35 |
| Caffeine intake frequency | ≤1 time/day | 91 (61.1) | 30.77±8.77 | 0.18 (0.859) |
| ≥2 times/day | 58 (38.9) | 30.50±9.33 |