Table 3.
Distribution of the cumulative occupational exposure after segmentation
| Variable | Control group | Case group | χ2 | P |
|---|---|---|---|---|
| Cumulative number of days of night work (day), n (%) | 10.267 | 0.006* | ||
| 0 | 97(15.1) | 143(9.5) | ||
| 0–1,972.80 | 280(43.7) | 173(44.0) | ||
| ≥ 1,972.80 | 264(41.2) | 168(46.5) | ||
| Cumulative exposure to heat (°C/year), n (%) | 24.525 | < 0.001* | ||
| 0 | 355(54.4) | 277(43.2) | ||
| 0–567.83 | 158(24.6) | 167(26.1) | ||
| ≥ 567.83 | 128(20.0) | 197(30.7) | ||
| Cumulative exposure to dust (mg/m3/year), n (%) | 14.532 | 0.001* | ||
| 0 | 457(71.3) | 394(61.5) | ||
| 0–30.02 | 96(15.0) | 119(18.5) | ||
| ≥ 30.02 | 88(13.7) | 128(20.0) | ||
| Cumulative noise exposure (dB(A)/year), n (%) | 0.886 | 0.642 | ||
| 0 | 288(44.9) | 277(43.2) | ||
| 0–1,660.68 | 181(28.2) | 177(27.6) | ||
| ≥ 1,660.68 | 172(26.8) | 187(29.2) |
*indicates statistical significance