Age at starting smoking (years, missing 11 cases) | Person-years | Case (n = 80) | Crude HR (95%CI) | p for trend | Adjusted HR (95%CI) a | p for trend |
---|---|---|---|---|---|---|
 Never smoker | 215,223.6 | 35 | 1.00 |  | 1.00 |  |
 26–42 | 38,618.8 | 18 | 2.88 (1.63–5.10) |  | 2.88 (1.38–5.99) |  |
 15–25 | 44,017.9 | 16 | 2.27 (1.26–4.11) |  < 0.001 | 2.71 (1.27–5.78) | 0.003 |
Frequency (session per day, missing 2 case) | ||||||
 Never smoker | 215,223.6 | 35 | 1.00 |  | 1.00 |  |
 One per week-10 per day | 52,706.7 | 25 | 2.98 (1.78–4.98) |  | 2.54 (1.33–4.84) |  |
 11–100 per day | 42,203.1 | 18 | 2.62 (1.48–4.62) |  < 0.001 | 2.31 (1.16–4.61) | 0.014 |
Duration of smoking (years, missing 23 cases) | ||||||
 Never smoker | 215,223.6 | 35 | 1.00 |  | 1.00 |  |
 1–15 | 30,682.6 | 8 | 1.64 (0.76–3.55) |  | 2.18 (0.90–5.29) |  |
 16–65 | 28,977.9 | 14 | 3.01 (1.62–5.59) |  < 0.001 | 2.35 (1.10–5.04) | 0.025 |
Cumulative smoking frequency (times, missing 3 cases) | ||||||
 Never smoker | 215,223.6 | 35 | 1.00 |  | 1.00 |  |
 1–164 | 45,557.0 | 17 | 2.34 (1.31–4.18) |  | 2.47 (1.22–4.99) |  |
 165–3,250 | 46,037.7 | 25 | 3.34 (2.00–5.59) |  < 0.001 | 2.60 (1.36–4.96) | 0.004 |