Results of multiple linear regression analyses of phase 2 and 3 lung function variables as dependent and factory, age, cumulative smoking, and indices of current or cumulative exposure to dust as independent variables
| Phase 2 | Phase 3 | ||||||
|---|---|---|---|---|---|---|---|
| Current inhalable β (95% CI) | Cumulative inhalable β (95% CI) | Current inhalable β (95% CI) | Cumulative inhalable β (95% CI) | ||||
| FEV1: | |||||||
| Ex-smoker | −0.01 (−0.07 to 0.06) | −0.01 (−0.08 to 0.06) | −0.05 (−0.11 to 0.02) | −0.05 (−0.11 to 0.02) | |||
| ⩽250 cigarette-y | −0.06 (−0.13 to 0.01) | −0.07 (−0.14 to 0.01) | −0.06 (−0.14 to 0.02) | −0.06 (−0.14 to 0.02) | |||
| 251–500 cigarette-y | −0.15 (−0.23 to −0.08) | −0.16 (−0.23 to −0.08) | −0.24 (−0.32 to −0.17) | −0.25 (−0.32 to −0.17) | |||
| >500 cigarette-y | −0.34 (−0.42 to −0.27) | −0.35 (−0.42 to −0.27) | −0.31 (−0.39 to −0.23) | −0.30 (−0.38 to −0.22) | |||
| Exposure to CB5-150 | −0.07 (−0.11 to −0.03) | −0.01 (−0.02 to 0.00) | −0.05 (−0.10 to 0.01) | −0.01 (−0.02 to −0.00) | |||
| FVC: | |||||||
| Ex-smoker | 0.06 (−0.02 to 0.14) | 0.06 (−0.02 to 0.13) | 0.01 (−0.07 to 0.09) | 0.01 (−0.07 to 0.09) | |||
| ⩽250 cigarette-y | −0.01 (−0.09 to 0.08) | −0.01 (−0.09 to 0.08) | −0.06 (−0.15 to 0.04) | −0.06 (−0.15 to 0.04) | |||
| 251–500 cigarette-y | 0.00 (−0.09 to 0.09) | 0.00 (−0.09 to 0.08) | −0.12 (−0.22 to −0.03) | −0.12 (−0.22 to −0.03) | |||
| >500 cigarette-y | −0.14 (−0.23 to −0.05) | −0.14 (−0.23 to −0.05) | −0.15 (−0.25 to −0.05) | −0.15 (−0.25 to −0.05) | |||
| Exposure to CB5-150 | −0.03 (−0.08 to 0.02) | 0.00 (−0.01 to 0.01) | −0.01 (−0.08 to 0.06) | 0.00 (−0.01 to 0.01) | |||
| FEF25%–75%: | |||||||
| Ex-smoker | −0.16 (−0.31 to −0.01) | −0.17 (−0.32 to −0.02) | −0.23 (−0.39 to −0.08) | −0.23 (−0.38 to −0.07) | |||
| ⩽250 cigarette-y | −0.16 (−0.33 to 0.01) | −0.18 (−0.35 to −0.01) | −0.09 (−0.27 to 0.10) | −0.09 (−0.28 to 0.09) | |||
| 251–500 cigarette-y | −0.56 (−0.74 to −0.38) | −0.57 (−0.75 to −0.39) | −0.60 (−0.79 to −0.42) | −0.61 (−0.79 to −0.42) | |||
| >500 cigarette-y | −0.87 (−1.05 to −0.69) | −0.88 (−1.06 to −0.70) | −0.79 (−0.98 to −0.60) | −0.78 (−0.97 to −0.59) | |||
| Exposure to CB5-150 | −0.16 (−0.25 to −0.06) | −0.02 (−0.04 to −0.00) | −0.15 (−0.28 to −0.02) | −0.03 (−0.05 to −0.01) | |||
| FEV1/FVC ratio: | |||||||
| Ex-smoker | −0.99 (−1.83 to −0.14) | −1.03 (−1.87 to −0.18) | −1.08 (−1.88 to −0.28) | −1.07 (−1.87 to −0.27) | |||
| ⩽250 cigarette-y | −1.14 (−2.09 to −0.19) | −1.23 (−2.18 to −0.28) | −0.36 (−1.33 to 0.60) | −0.38 (−1.34 to 0.58) | |||
| 251–500 cigarette-y | −2.70 (−3.69 to −1.72) | −2.78 (−3.77 to −1.79) | −2.78 (−3.74 to −1.82) | −2.78 (−3.74 to −1.83) | |||
| >500 cigarette-y | −4.75 (−5.75 to −3.75) | −4.79 (−5.80 to −3.79) | −3.95 (−4.93 to −2.98) | −3.88 (−4.85 to −2.90) | |||
| Exposure to CB5-150 | −0.89 (−1.42 to −0.35) | −0.12 (−0.23 to −0.02) | −0.76 (−1.45 to −0.08) | −0.17 (−0.28 to −0.06) | |||
↵5-150 Regression coefficients are given in litres (FEV1and FVC), l.s−1 (FEF25–75), or % (FEV1/FVC ratio) for an increase in exposure of 1 mg.m−3 (current exposure) or 100 mg.month.m−3 (cumulative exposure).
Regression coefficients (95% CIs) in italic mean that these are significantly different from 0 (p<0.05).
CB=carbon black.