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 incidence		Death
	HR (95% CI) β1	P	HR (95% CI) β2	P
Smoking intensity ≤ 15	1.111 (1.084–1.139)	<10−16	1.051 (1.041–1.062)	<10−16
	Weibull hazard parameters		Weibull hazard parameters
Strata	Shape (95% CI) λ1	Scale (95% CI) γ1	Shape (95% CI) λ2	Scale (95% CI) γ2
t ≤ 18	3.819 (3.750–3.869)	0.999 (0.772–1.162)	3.690 (3.659–3.713)	1.220 (1.105–1.302)
18 < t ≤ 20	4.056 (3.966–4.121)	1.071 (0.870–1.215)	3.774 (3.748–3.793)	1.312 (1.210–1.384)
20 < t ≤ 22	4.230 (4.134–4.299)	1.298 (1.144–1.408)	3.859 (3.839–3.873)	1.560 (1.489–1.611)
22 < t ≤ 24	4.339 (4.234–4.414)	1.518 (1.374–1.621)	3.944 (3.924–3.958)	1.775 (1.715–1.818)
24 < t ≤ 26	4.380 (4.258–4.468)	1.679 (1.519–1.794)	3.979 (3.958–3.995)	1.925 (1.865–1.969)
26 < t ≤ 28	4.567 (4.361–4.714)	1.517 (1.294–1.677)	4.049 (4.017–4.071)	1.854 (1.773–1.911)
28 < t ≤ 30	4.506 (4.278–4.670)	1.615 (1.344–1.809)	4.096 (4.049–4.130)	1.838 (1.727–1.917)
30 < t	4.504 (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 incidence		Death
	HR (95% CI) β1	P	HR (95% CI) β2	P
Smoking intensity ≤ 15	1.043 (1.012–1.076)	0.007	1.015 (1.006–1.023)	<10−16
	Weibull hazard parameters		Weibull hazard parameters
Strata	Shape (95% CI) λ1	Scale (95% CI) γ1	Shape (95% CI) λ2	Scale (95% CI) γ2
t ≤ 22; s ≤ 20	4.987 (4.372–5.427)	0.750 (0.359–1.029)	3.754 (3.722–3.776)	1.210 (1.128–1.269)
20 < s ≤ 30	4.723 (4.242–5.066)	0.819 (0.409–1.112)	3.750 (3.726–3.767)	1.511 (1.428–1.570)
30 < s	4.321 (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 ≤ 20	5.179 (4.537–5.638)	1.165 (0.795–1.430)	4.008 (3.975–4.032)	1.621 (1.555–1.668)
20 < s ≤ 30	4.786 (4.335–5.108)	1.353 (0.989–1.612)	3.975 (3.942–3.998)	1.742 (1.663–1.799)
30 < s ≤ 36	4.651 (4.132–5.022)	1.460 (0.945–1.829)	3.954 (3.921–3.977)	1.835 (1.734–1.907)
36 < s ≤ 42	4.654 (4.034–5.097)	1.318 (0.639–1.804)	3.928 (3.903–3.945)	2.129 (2.018–2.208)
42 < s	4.366 (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 ≤ 20	5.563 (4.668–6.202)	1.088 (0.640–1.409)	4.123 (4.087–4.148)	1.769 (1.698–1.820)
20 < s ≤ 30	4.680 (4.223–5.007)	1.705 (1.249–2.032)	4.058 (4.026–4.082)	1.865 (1.781–1.926)
30 < s ≤ 36	4.491 (4.062–4.797)	1.879 (1.312–2.283)	4.020 (3.986–4.044)	2.148 (2.027–2.234)
36 < s ≤ 42	4.241 (3.990–4.420)	2.336 (1.754–2.751)	3.999 (3.968–4.021)	2.360 (2.213–2.465)
42 < s	4.177 (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.