Effects of quitting duration and previous smoking amount on the risk of subarachnoid haemorrhage
| Variables | Crude OR (95% CI) | Adjusted OR (95% CI)* compared to non-smokers | Adjusted OR (95% CI) compared to current smokers |
| Non-smokers (n=536) | 1.00 (reference) | 1.00 (reference) | 0.35 (0.20 to 0.61) |
| Past smokers | |||
| Cigarettes per day (n) | |||
| 1–19 (n=21) | 0.95 (0.33 to 2.69) | 0.99 (0.32 to 3.06) | 0.36 (0.13 to 1.01) |
| ≥20 (n=44) | 2.17 (1.03 to 4.60) | 2.34 (1.02 to 5.36) | 0.84 (0.40 to 1.78) |
| Time since quitting (years) | |||
| ≥5 (n=35) | 1.22 (0.53 to 2.82) | 1.17 (0.46 to 3.00) | 0.41 (0.17 to 0.97) |
| <5 (n=30) | 2.40 (1.02 to 5.63) | 2.71 (1.07 to 6.81) | 0.94 (0.41 to 2.16) |
| Current smokers (n=251) | 2.79 (1.72 to 4.51) | 2.84 (1.63 to 4.97) | 1.00 (reference) |
↵* Adjusted for family history of stroke, hypertension, diabetes, hyperlipidaemia and cardiovascular diseases as well as body mass index, alcohol consumption, high salt intake and laborious work hours.