Table 2.

Weibull parameters and HRs of smoking intensity used in Equation (A) for the lung cancer incidence and death models for current and former smokers

Current smokers
Lung cancer incidenceDeath
HR (95% CI) β1PHR (95% CI) β2P
Smoking intensity ≤ 151.111 (1.084–1.139)<10−161.051 (1.041–1.062)<10−16
Weibull hazard parametersWeibull hazard parameters
StrataShape (95% CI) λ1Scale (95% CI) γ1Shape (95% CI) λ2Scale (95% CI) γ2
t ≤ 183.819 (3.750–3.869)0.999 (0.772–1.162)3.690 (3.659–3.713)1.220 (1.105–1.302)
 18 < t ≤ 204.056 (3.966–4.121)1.071 (0.870–1.215)3.774 (3.748–3.793)1.312 (1.210–1.384)
 20 < t ≤ 224.230 (4.134–4.299)1.298 (1.144–1.408)3.859 (3.839–3.873)1.560 (1.489–1.611)
 22 < t ≤ 244.339 (4.234–4.414)1.518 (1.374–1.621)3.944 (3.924–3.958)1.775 (1.715–1.818)
 24 < t ≤ 264.380 (4.258–4.468)1.679 (1.519–1.794)3.979 (3.958–3.995)1.925 (1.865–1.969)
 26 < t ≤ 284.567 (4.361–4.714)1.517 (1.294–1.677)4.049 (4.017–4.071)1.854 (1.773–1.911)
 28 < t ≤ 304.506 (4.278–4.670)1.615 (1.344–1.809)4.096 (4.049–4.130)1.838 (1.727–1.917)
 30 < t4.504 (4.317–4.637)1.684 (1.454–1.848)4.069 (4.040–4.090)1.912 (1.835–1.966)
Former smokers
Lung cancer incidenceDeath
HR (95% CI) β1PHR (95% CI) β2P
Smoking intensity ≤ 151.043 (1.012–1.076)0.0071.015 (1.006–1.023)<10−16
Weibull hazard parametersWeibull hazard parameters
StrataShape (95% CI) λ1Scale (95% CI) γ1Shape (95% CI) λ2Scale (95% CI) γ2
t ≤ 22; s ≤ 204.987 (4.372–5.427)0.750 (0.359–1.029)3.754 (3.722–3.776)1.210 (1.128–1.269)
 20 < s ≤ 304.723 (4.242–5.066)0.819 (0.409–1.112)3.750 (3.726–3.767)1.511 (1.428–1.570)
 30 < s4.321 (4.140–4.450)1.032 (0.733–1.246)3.800 (3.785–3.810)1.669 (1.603–1.716)
 22 < t ≤ 26; s ≤ 205.179 (4.537–5.638)1.165 (0.795–1.430)4.008 (3.975–4.032)1.621 (1.555–1.668)
 20 < s ≤ 304.786 (4.335–5.108)1.353 (0.989–1.612)3.975 (3.942–3.998)1.742 (1.663–1.799)
 30 < s ≤ 364.651 (4.132–5.022)1.460 (0.945–1.829)3.954 (3.921–3.977)1.835 (1.734–1.907)
 36 < s ≤ 424.654 (4.034–5.097)1.318 (0.639–1.804)3.928 (3.903–3.945)2.129 (2.018–2.208)
 42 < s4.366 (4.090–4.563)1.662 (1.136–2.038)3.982 (3.961–3.998)2.150 (2.040–2.229)
t > 26; s ≤ 205.563 (4.668–6.202)1.088 (0.640–1.409)4.123 (4.087–4.148)1.769 (1.698–1.820)
 20 < s ≤ 304.680 (4.223–5.007)1.705 (1.249–2.032)4.058 (4.026–4.082)1.865 (1.781–1.926)
 30 < s ≤ 364.491 (4.062–4.797)1.879 (1.312–2.283)4.020 (3.986–4.044)2.148 (2.027–2.234)
 36 < s ≤ 424.241 (3.990–4.420)2.336 (1.754–2.751)3.999 (3.968–4.021)2.360 (2.213–2.465)
 42 < s4.177 (4.052–4.266)2.574 (2.123–2.896)4.041 (4.007–4.066)2.490 (2.295–2.629)

NOTE: Parameter estimates are based on maximum likelihood estimates, 95% CIs are in parentheses. Time zero set to 35 years old.

Abbreviations: s, smoking duration; t, age start smoke.