Table 4
Results of regression analyses for annual rates of change (time slopes) for FVC, FEV1, and FEV1/FVC for subjects in the coke oven lung function surveillance system after the exclusion of 111 subjects without detailed work histories
| FVC (ml/year) | FEV1 (ml/year) | FEV1/FVC (%/year) | FEF25–75% (ml/s⋅year) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Coefficient | 95% CI | p value | Coefficient | 95% CI | p value | Coefficient | 95% CI | p value | Coefficient | 95% CI | p value | |
| FEF25–75% was measured after January 1983, so the observation number is smaller than that for FVC, FEV1, and FEV1/FVC. | ||||||||||||
| Intercept | 33.9 | 4.19 to 63.6 | 0.0254 | 49.8 | 24.2 to 75.3 | 0.0001 | 3.3 | 2.61 to 4.00 | 0.0001 | 100 | 27.8 to 173 | 0.0068 |
| % of predicted value at first test time | −0.386 | −0.698 to −0.072 | 0.0159 | −0.531 | −0.792 to −0.270 | 0.0001 | −0.0323 | −0.038 to −0.025 | 0.0001 | −0.674 | −1.31 to −0.035 | 0.0388 |
| Duration of smoking for ex-smokers (y) | −0.373 | −0.771 to 0.024 | 0.0657 | −0.596 | −0.986 to −0.206 | 0.0028 | −0.0130 | −0.019 to −0.006 | 0.0001 | −0.997 | −2.82 to 0.824 | 0.283 |
| Pack-years for current smokers | −0.477 | −0.784 to −0.170 | 0.0024 | −0.661 | −0.962 to −0.360 | 0.0001 | −0.0107 | −0.015 to −0.005 | 0.0001 | −1.29 | −2.64 to 0.0670 | 0.0624 |
| Work duration in “operation” (y) | −1.03 | −1.72 to −0.334 | 0.0038 | −0.762 | −1.44 to −0.080 | 0.0284 | −0.00110 | −0.012 to 0.010 | 0.852 | −0.666 | −3.82 to 2.48 | 0.678 |
| Work duration other than in “operation” (y) | −0.661 | −1.24 to −0.075 | 0.0270 | −0.472 | −1.04 to 0.101 | 0.106 | 0.00225 | −0.007 to 0.012 | 0.651 | 0.0277 | −2.64 to 2.69 | 0.984 |
| R2 | 0.0559 | 0.0834 | 0.185 | 0.0193 | ||||||||
| Number of observations | 469 | 469 | 469 | 355 | ||||||||
