From: Radon exposure and lung cancer: risk in nonsmokers among cohort studies
 | Cumulative exposure to radon progeny from uranium mining (WLM) | Trend slope, cases/WLM person-year | |||
---|---|---|---|---|---|
<120 | 120– < 400 | 400– < 1000 | > − 1000 | ||
Never smoker | 4.5 × 10−6c | ||||
 No. | 2 | 9 | 22 | 43 | |
 SMR (95 % CI) | 0.25 (0.03–0.89) | 0.87 (0.40–1.7) | 2.9 (1.8–4.4) | 6.3 (4.6–8.5) | |
 SRR (95 % CI) | 1.0 (ref) | 3.5 (0.75–16) | 13 (3.0–54) | 29 (7.0–120) |