Table 2 General characteristics of the male workers
From: Comparison of sleep quality based on direction of shift rotation in electronics workers
| Â | Total | Forward rotation | Backward rotation | P value* |
|---|---|---|---|---|
Number of participants | 1749 | 1359 (77.7) | 390 (22.3) | Â |
Age, years | 28.4 ± 4.5 | 28.4 ± 4.7 | 28.2 ± 3.4 | 0.685 |
BMI, kg/m2 | 24.5 ± 3.4 | 24.5 ± 3.5 | 24.2 ± 3.3 | 0.124 |
Duration of shift work | Â | Â | Â | <0.001 |
 <5 years | 1134 | 823 (72.6) | 311 (27.4) |  |
 5–9 years | 414 | 358 (86.5) | 56 (13.5) |  |
 ≥10 years | 201 | 178 (88.6) | 23 (11.4) |  |
Weekly working hours | Â | Â | Â | <0.001 |
 <41 h | 416 | 368 (88.5) | 48 (11.5) |  |
 41–51 h | 947 | 742 (78.4) | 205 (21.6) |  |
 52–59 h | 311 | 206 (66.2) | 105 (33.8) |  |
 ≥60 h | 75 | 43 (57.3) | 32 (42.7) |  |
Smoking status | Â | Â | Â | 0.379 |
 Non-smoker | 935 | 716 (76.6) | 219 (23.4) |  |
 Ex-smoker | 788 | 621 (78.8) | 167 (21.2) |  |
 Current smoker | 26 | 22 (84.6) | 4 (15.4) |  |
Alcohol consumption | Â | Â | Â | 0.534 |
 Non-drinker | 384 | 292 (76.0) | 92 (24.0) |  |
 Regular drinker | 1251 | 975 (77.9) | 276 (22.1) |  |
 Heavy drinker | 114 | 92 (80.7) | 22 (19.3) |  |
Physical activity | Â | Â | Â | 0.454 |
 Sufficient exercise | 802 | 630 (78.6) | 172 (21.4) |  |
 Insufficient exercise | 947 | 729 (77.0) | 218 (23.0) |  |
Sleep duration, hours | 6.8 ± 1.4 | 6.8 ± 1.4 | 6.9 ± 1.4 | 0.158 |
PSQI score, points | 4.1 ± 2.5 | 3.9 ± 2.5 | 4.7 ± 2.5 | <0.001 |