Risk factor-adjusted incidence and relative hazards of haemorrhagic stroke by radiation exposure
| Radiation exposure (Gy) | Incidence | Relative hazard (95% CI) |
| Men | ||
| <0.05 | 11.6 | Reference |
| 0.05 to <1 | 17.7 | 1.5 (0.8 to 2.7) |
| 1 to <2 | 20.2 | 1.7 (0.7 to 4.1) |
| ≥2 | 29.1 | 2.5 (0.8 to 7.3) |
| p Value* | 0.009† | |
| Women | ||
| <0.05 | 14.2 | Reference |
| 0.05 to <1.3 | 13.0 | 0.9 (0.6 to 1.4) |
| 1.3 to <2.2 | 20.3 | 1.4 (0.6 to 3.7) |
| ≥2.2 | 48.6 | 3.5 (1.4 to 9.0) |
| p Value | 0.002 | |
Incidence rate per 10 000 person-years and relative hazards are adjusted for age, systolic blood pressure, body mass index, diabetes, total cholesterol, cigarette smoking, alcohol drinking and city.
↵* The p value is a test for trend with dose modelled as a continuous variable. For women, a dose threshold model is used with a dose threshold at 1.3 Gy (95% CI 0.5 to 2.3 Gy).
↵† For men, risk of haemorrhagic stroke continued to rise with increasing doses <1 Gy (p=0.004).