Table 5.
Silicosis (defined as ILO 1/0) hazard ratios (HRs) and 95% confidence intervals (95% CI) for the full cohort, lagged 10 years and limited to those hired since 1960, by categories of cumulative (mg/m3-years) and average exposure (mg/m3), and duration of employment (decades), stratified by sex and controlling for age and smoking.
| HR (95% CI) | ||||||
|---|---|---|---|---|---|---|
| Full cohort | Exposure lagged 10 years | Limited to those hired since 1960 | ||||
| Observed | Observed | Observed | ||||
| Cumulative exposure | ||||||
| ≤0.5 | 6 | Reference | 9 | Reference | 6 | Reference |
| >0.5–1.0 | 7 | 1.6 (0.5–5.0) | 12 | 3.4 (1.4–8.8) | 7 | 1.8 (0.6–5.4) |
| >1.0–1.5 | 13 | 4.8 (1.7–13.5) | 9 | 4.0 (1.4–10.9) | 12 | 5.4 (1.9–15.3) |
| >1.5–3.0 | 15 | 3.6 (1.3–10.1) | 14 | 3.8 (1.5–9.8) | 9 | 5.2 (1.7–15.3) |
| >3.0–4.0 | 7 | 4.8 (1.5–15.5) | 7 | 5.6 (1.9–16.5) | 3 | 5.4 (1.3–22.4) |
| >4–5 | 4 | 3.9 (1.0–14.8) | 5 | 5.2 (1.6–17.0) | 1 | 3.6 (0.4–30.6) |
| >5–6 | 9 | 9.5 (3.1–29.3) | 6 | 7.0 (2.2–22.0) | 1 | 9.4 (1.1–81.6) |
| >6 | 47 | 16.3 (6.1–43.4) | 46 | 18.8 (7.8–45.3) | 2 | 6.0 (1.1–31.8) |
| Average exposure‡ | ||||||
| ≤0.05 | 19 | Reference | ||||
| >0.05–0.1 | 19 | 1.7 (0.9–3.4) | ||||
| >0.1–0.15 | 10 | 2.0 (0.9–4.5) | ||||
| >0.15–0.2 | 24 | 4.7 (2.4–9.4) | ||||
| >0.2 | 36 | 8.4 (4.5–15.8) | ||||
| Years employed | ||||||
| ≤10 | 5 | Reference | 5 | Reference | ||
| >10–20 | 15 | 1.0 (0.4–2.8) | 14 | 1.0 (0.4–2.7) | ||
| >20–30 | 23 | 1.4 (0.5–3.8) | 16 | 1.2 (0.4–3.5) | ||
| >30 | 65 | 2.7 (1.0–7.3) | 6 | 1.4 (0.4–4.8) | ||
| Smoking | ||||||
| Never | 25 | Reference | 13 | Reference | ||
| Ever | 49 | 2.2 (1.3–3.5) | 24 | 1.8 (0.9–3.5) | ||
| Unknown | 34 | 1.1 (0.6–1.8) | 4 | 0.4 (0.1–1.2) | ||
Also, HRs by smoking status controlling for age. ‡Additionally adjusted for duration of employment.