Univariate analysis of individual and ergonomic factors with chronic LBP among ambulance nurses
| Factors | Chronic LBP | Non-chronic-LBP | P value |
| Number of subjects | 105 | 393 | |
| Age (years)* | 36.5±7.7 | 29.7±6.7 | <0.001† |
| Sex | 0.022‡ | ||
| Male | 8 | 65 | |
| Female | 97 | 328 | |
| BMI | <0.001§ | ||
| ＜18.5 (Underweight) | 4 | 39 | |
| 18.5～23.9 (Normal weight) | 45 | 231 | |
| 24.0～27.9 (Overweight) | 29 | 96 | |
| ≥28.0 (Obesity) | 27 | 27 | |
| Whether takes shift work? | <0.001‡ | ||
| Yes (Shift work) | 60 | 129 | |
| No (Day work) | 45 | 264 | |
| Work experience as an ambulance worker (years)* | 13.8±8.7 | 6.8±7.2 | <0.001† |
| Employment status | 0.014‡ | ||
| Permanent | 39 | 199 | |
| Temporary/contract | 66 | 194 | |
| Ergonomic factors | |||
| Walking for long periods of time (Yes/No) | 54/51 | 154/239 | 0.024‡ |
| Frequent bending of the trunk (Yes/No) | 66/39 | 93/300 | <0.001‡ |
| Heavy or awkward lifting (Yes/No) | 75/30 | 112/281 | <0.001‡* |
| Bending or twisting the neck (Yes/No) | 39/66 | 97/296 | 0.011‡* |
| Maintaining shoulder abduction for long periods of time (Yes/No) | 48/57 | 136/257 | 0.036‡* |
*Mean± standard deviation.
†t;t-test.
‡χ2 test.
§Rank-sum test.