Poisson regression analysis of mortality (rate ratio) from asthma, chronic bronchitis, and emphysema combined by smoking habit and cumulative exposure to total dust (mg/m3.y), controlled for age (<65, 65–69, 70–74, 75–79, ≥80) and calendar period (1962–79,1980–96) (restricted to workers employed for >3 y)
| Smoking included | Smoking not included | ||||
|---|---|---|---|---|---|
| Deaths (n) | Rate ratio | 95% CI | Rate ratio | 95% CI | |
| *Mean dose; arithmetic mean cumulative exposure of total dust. | |||||
| Smoking status: | |||||
| Never | 3 | 1.0 | Reference | – | – |
| Former | 2 | 2.0 | 0.3 to 12.1 | – | – |
| Smoker | 22 | 3.4 | 1.0 to 11.5 | – | – |
| Unknown | 2 | 1.6 | 0.3 to 9.8 | ||
| Exposure to total dust (mg/m3.y): | |||||
| 0 | 1 | 1.0 | Reference | 1.0 | Reference |
| 0.1–14.9 | 2 | 3.0 | 0.3 to 33.4 | 3.7 | 0.3 to 40.9 |
| 15–69.9 | 12 | 4.5 | 0.6 to 34.4 | 4.5 | 0.6 to 35.0 |
| ≥70 | 14 | 5.1 | 0.7 to 38.9 | 5.5 | 0.7 to 42.1 |
| Evaluation of linear trend: | p Value | p Value | |||
| Scores 1,2,3,4 | 0.07 | 0.08 | |||
| Mean dose* | 0.10 | 0.16 | |||