Multivariate logistic regression analysis of chronic LBP risk factors among ambulance doctors and among ambulance drivers
| Factors | B | SE | P value | OR (95% CI) |
| For doctors' chronic LBP | ||||
| Age (years) | 1.031 | 0.448 | <0.001 | 2.804 (1.165 to 6.747) |
| Sex (1=female, 0=male) | 0.502 | 0.253 | 0.034 | 1.652 (1.006 to 2.713) |
| BMI | ||||
| 18.5～23.9 (Normal weight) | Reference | |||
| ＜18.5 (Underweight) | −0.537 | 0.512 | 0.427 | 0.584 (0.214 to 1.594) |
| 24.0～27.9 (Overweight) | 0.556 | 0.309 | 0.141 | 1.744 (0.952 to 3.195) |
| ≥28.0 (Obesity) | 1.571 | 0.322 | <0.001 | 4.811 (2.560 to 9.044) |
| Ergonomic factors | ||||
| Frequent bending of the trunk (1=yes, 0=no) | 1.313 | 0.352 | <0.001 | 3.717 (1.865 to 7.411) |
| Psychosocial factors | ||||
| Occupational stress | ||||
| Psychological job demand | 1.055 | 0.401 | <0.001 | 2.872 (1.309 to 6.303) |
| For drivers' chronic LBP | ||||
| Age (years) | 1.115 | 0.501 | 0.004 | 3.050 (1.142 to 8.141) |
| BMI | ||||
| 18.5～23.9 (Normal weight) | Reference | |||
| ＜18.5 (Underweight) | −0.722 | 0.473 | 0.643 | 0.486 (0.192 to 1.228) |
| 24.0～27.9 (Overweight) | 0.948 | 0.305 | <0.001 | 2.581 (1.419 to 4.692) |
| ≥28.0 (Obesity) | 1.804 | 0.354 | <0.001 | 6.074 (3.035 to 12.156) |
| Ergonomic factors | ||||
| Sitting for long periods of time (1=yes, 0=no) | 1.936 | 0.315 | <0.001 | 6.931 (3.738 to 12.851) |
| Psychosocial factors | ||||
| Psychological fatigue | ||||
| Low | Reference | |||
| Medium | 0.557 | 0.275 | 0.002 | 1.745 (1.018 to 2.992) |
| High | 1.011 | 0.311 | <0.001 | 2.748 (1.494 to 5.056) |