Results of the phase 2 and 3 logistic regression models with respiratory symptom as dependent variable and factory, age, cumulative smoking, and current or cumulative exposure to inhalable dust as the independent variables
| Phase 2 | Phase 3 | ||||||
|---|---|---|---|---|---|---|---|
| Current inhalable OR (95% CI) | Cumulative inhalable OR (95% CI) | Current inhalable OR (95% CI) | Cumulative inhalable OR (95% CI) | ||||
| Cough: | |||||||
| Ex-smoker | 1.3 (0.8 to 2.2) | 1.3 (0.8 to 2.2) | 0.7 (0.4 to 1.2) | 0.7 (0.4 to 1.2) | |||
| ⩽250 cigarette-y | 2.7 (1.6 to 4.5) | 2.8 (1.7 to 4.6) | 1.8 (1.0 to 3.1) | 1.8 (1.0 to 3.0) | |||
| 251–500 cigarette-y | 4.0 (2.5 to 6.6) | 4.1 (2.5 to 6.7) | 3.7 (2.3 to 5.9) | 3.7 (2.3 to 5.9) | |||
| >500 cigarette-y | 11.0 (6.8 to 17.7) | 11.1 (6.9 to 17.9) | 6.7 (4.2 to 10.6) | 6.5 (4.1 to 10.3) | |||
| Exposure to CB4-150 | 1.4 (1.2 to 1.8) | 1.1 (1.0 to 1.1) | 1.5 (1.1 to 2.1) | 1.1 (1.1 to 1.2) | |||
| Sputum production: | |||||||
| Ex-smoker | 1.2 (0.8 to 1.9) | 1.2 (0.8 to 1.9) | 1.0 (0.6 to 1.7) | 1.0 (0.6 to 1.7) | |||
| ⩽250 cigarette-y | 2.8 (1.8 to 4.4) | 2.9 (1.9 to 4.5) | 2.1 (1.2 to 3.6) | 2.1 (1.2 to 3.6) | |||
| 251–500 cigarette-y | 3.1 (2.0 to 4.8) | 3.1 (2.0 to 4.9) | 2.9 (1.8 to 4.8) | 3.0 (1.8 to 4.9) | |||
| >500 cigarette-y | 5.8 (3.8 to 9.0) | 5.9 (3.8 to 9.1) | 5.3 (3.3 to 8.7) | 5.3 (3.3 to 8.6) | |||
| Exposure to CB4-150 | 1.3 (1.0 to 1.5) | 1.0 (1.0 to 1.1) | 1.4 (1.0 to 1.9) | 1.0 (1.0 to 1.1) | |||
| Cough with sputum production: | |||||||
| Ex-smoker | 1.3 (0.7 to 2.5) | 1.4 (0.7 to 2.6) | 0.7 (0.3 to 1.4) | 0.7 (0.3 to 1.4) | |||
| ⩽250 cigarette-y | 2.5 (1.3 to 4.8) | 2.6 (1.4 to 5.0) | 2.0 (1.0 to 4.0) | 2.0 (1.0 to 4.0) | |||
| 251–500 cigarette-y | 3.4 (1.8 to 6.3) | 3.4 (1.8 to 6.4) | 3.9 (2.1 to 7.2) | 3.9 (2.1 to 7.2) | |||
| >500 cigarette-y | 8.3 (4.6 to 14.8) | 8.5 (4.8 to 15.3) | 5.6 (3.1 to 10.1) | 5.4 (3.0 to 9.9) | |||
| Exposure to CB4-150 | 1.5 (1.2 to 1.9) | 1.1 (1.0 to 1.1) | 1.6 (1.0 to 2.3) | 1.1 (1.0 to 1.2) | |||
| Chronic bronchitis: | |||||||
| Ex-smoker | 0.8 (0.3 to 1.9) | 0.9 (0.4 to 2.1) | 1.2 (0.5 to 3.2) | 1.2 (0.5 to 3.2) | |||
| ⩽250 cigarette-y | 1.6 (0.7 to 3.9) | 1.7 (0.7 to 4.2) | 1.4 (0.4 to 4.6) | 1.4 (0.4 to 4.6) | |||
| 251–500 cigarette-y | 2.1 (0.9 to 4.9) | 2.2 (1.0 to 5.2) | 4.0 (1.6 to 10.2) | 4.1 (1.7 to 10.4) | |||
| >500 cigarette-y | 5.8 (2.8 to 12.2) | 6.2 (3.0 to 12.9) | 6.6 (2.7 to 15.7) | 6.5 (2.7 to 15.5) | |||
| Exposure to CB4-150 | 1.8 (1.3 to 2.6) | 1.1 (1.0 to 1.2) | 1.6 (0.9 to 2.7) | 1.1 (1.0 to 1.2) | |||
↵4-150 ORs for carbon black (CB) exposure are given for an increase in exposure of 1 mg.m−3 (current exposure) or 100 mg.month.m−3 (cumulative exposure).
ORs (95% CIs) in italic mean that these are significantly different from 1 (p<0.05).