Table 4.
Multiple linear regression analyses of lung function in relation to dust exposure, overall and stratified by smoking status
| Lung function | INH (µg/m3) | RES (µg/m3) | ||
|---|---|---|---|---|
| Coefficient (95% CI)a | P | Coefficient (95% CI)a | P | |
| Overall | ||||
| FEV1 | – 0.009 ( – 0.014, – 0.004) | < 0.001 | 0.002 ( – 0.006, 0.010) | 0.647 |
| FVC | – 0.006 ( – 0.011, – 0.002) | 0.006 | – 0.001 ( – 0.009, 0.007) | 0.793 |
| FEV1/FVC | – 0.002 ( – 0.005, 0.000) | 0.077 | 0.003 ( – 0.001, 0.007) | 0.165 |
| Smokers | ||||
| FEV1 | – 0.014 ( – 0.026, – 0.001) | 0.028 | 0.007 ( – 0.008, 0.021) | 0.352 |
| FVC | – 0.023 ( – 0.038, – 0.007) | 0.004 | – 0.002 ( – 0.015, 0.010) | 0.741 |
| FEV1/FVC | 0.001 ( – 0.001, 0.002) | 0.480 | – 0.006 ( – 0.016, 0.005) | 0.291 |
| Non-smokers | ||||
| FEV1 | – 0.006 ( – 0.015, 0.003) | 0.190 | – 0.002 ( – 0.010, 0.005) | 0.566 |
| FVC | – 0.006 ( – 0.017, 0.005) | 0.305 | 0.002 ( – 0.005, 0.009) | 0.515 |
| FEV1/FVC | – 0.000 ( – 0.001, 0.001) | 0.590 | – 0.003 ( – 0.011, 0.004) | 0.393 |
CI confidence interval
aAdjusted for age (years), gender (female, male), occupation (manager, surface production, underground mining), shift length (10 h, 12 h) and additional adjustment for smoking status (yes, no) in overall models; dust concentration was square-root transformed before being fitted in the linear regression models