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Table 2 General characteristics of the male workers

From: Comparison of sleep quality based on direction of shift rotation in electronics workers

  Total Forward rotation Backward rotation P value*
Number of participants 1749 1359 (77.7) 390 (22.3)  
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     <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     <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     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     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     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
  1. Values are number (%) or mean ± Standard Deviation (SD), unless otherwise indicated
  2. P value* = Chi-square test or Mann-Whitney test