Table 5
Relative risks (RR) and 95% confidence intervals (CI) for lung cancer mortality, adjusted for age and smoking, in male German carbon black workers traced alive on 1 January 1976
| Variable with levels | All workers, main (census) cohort | Workers hired 1960 or later, inception cohort | ||||
|---|---|---|---|---|---|---|
| Deaths | RR | 95% CI | RR | 95% CI | ||
| Period of hiring (calendar time) | ||||||
| <1950 | 4 | 0.30 | 0.10–0.87 | |||
| 1950–59 | 6 | 0.29 | 0.12–0.72 | |||
| 1960–69 | 31 | 1.00 | 31 | 1.00 | ||
| 1970–79 | 9 | 1.45 | 0.64–3.28 | 9 | 1.70 | 0.73–3.96 |
| 1980–97 | 0 | 0 | ||||
| Trend (10 years) | 1.61 | 1.14–2.28 | 1.06 | 0.54–2.09 | ||
| Age at hiring (years) | ||||||
| ⩽25 | 5 | 1.00 | 2 | 1.00 | ||
| >25–35 | 12 | 1.22 | 0.42–3.55 | 10 | 1.85 | 0.39–8.80 |
| >35–45 | 19 | 2.10 | 0.72–6.07 | 17 | 2.03 | 0.40–10.39 |
| >45 | 14 | 2.74 | 0.85–8.85 | 11 | 1.56 | 0.25–9.77 |
| Trend (10 years) | 1.46 | 1.03–2.05 | 1.03 | 0.64–1.67 | ||
| Time since hiring (years), time dependent | ||||||
| >0–15 | 7 | 1.00 | 7 | 1.00 | ||
| >15–25 | 15 | 0.68 | 0.26–1.77 | 15 | 0.63 | 0.24–1.65 |
| >25 | 28 | 0.49 | 0.18–1.34 | 18 | 0.56 | 0.20–1.57 |
| Trend (10 years) | 0.73 | 0.47–1.12 | 0.79 | 0.50–1.25 | ||
| Years of employment, time dependent | ||||||
| 1–5 | 12 | 1.00 | 12 | 1.00 | ||
| >5–10 | 9 | 0.92 | 0.37–2.25 | 8 | 1.05 | 0.40–2.74 |
| >10–20 | 16 | 0.70 | 0.30–1.61 | 13 | 0.84 | 0.34–2.09 |
| >20 | 13 | 0.39 | 0.16–0.94 | 7 | 0.96 | 0.33–2.81 |
| Trend (10 years) | 0.70 | 0.52–0.94 | 0.97 | 0.66–1.43 | ||
| At least 1 year employment in lamp or furnace black | ||||||
| No | 28 | 1.00 | 22 | 1.00 | ||
| Yes | 22 | 1.48 | 0.84–2.61 | 18 | 1.04 | 0.56–1.96 |
| At least 1 year employment in gas black | ||||||
| No | 37 | 1.00 | 32 | 1.00 | ||
| Yes | 13 | 1.07 | 0.57–2.02 | 8 | 1.21 | 0.55–2.64 |
| At least one year employment in preparation plant | ||||||
| No | 46 | 1.00 | 36 | 1.00 | ||
| Yes | 4 | 1.05 | 0.37–2.95 | 4 | 1.07 | 0.38–3.03 |
| At least one year employment in heavily exposed jobs | ||||||
| No | 16 | 1.00 | 14 | 1.00 | ||
| Yes | 34 | 1.29 | 0.71–2.34 | 26 | 0.98 | 0.51–1.89 |
| Average carbon black exposure (carbon black scores per year), time dependent | ||||||
| 0–1 | 12 | 1.00 | 9 | 1.00 | ||
| >1–2 | 14 | 1.06 | 0.49–2.28 | 14 | 1.53 | 0.66–3.55 |
| >2–3 | 21 | 0.97 | 0.47–1.98 | 15 | 1.13 | 0.49–2.60 |
| >3 | 3 | 0.39 | 0.11–1.39 | 2 | 0.40 | 0.09–1.86 |
| Trend (1 unit) | 0.85 | 0.65–1.10 | 0.86 | 0.64–1.15 | ||
| Cumulative carbon black exposure, time dependent | ||||||
| 0–5 | 10 | 1.00 | 9 | 1.00 | ||
| >5–10 | 10 | 1.07 | 0.44–2.59 | 8 | 0.97 | 0.37–2.54 |
| >10–20 | 9 | 0.84 | 0.34–2.10 | 9 | 1.03 | 0.40–2.67 |
| >20–40 | 12 | 0.70 | 0.29–1.70 | 12 | 1.27 | 0.52–3.08 |
| >40 | 9 | 0.28 | 0.11–0.72 | 2 | 0.21 | 0.04–0.99 |
| Trend (10 units) | 0.79 | 0.68–0.91 | 9 | 0.84 | 0.69–1.01 | |
| Total | 50 | 40 | ||||
