Age at quitting smoking as a predictor of risk of cardiovascular disease incidence independent of smoking status, time since quitting and pack-years

Table 6 Risk equation incorporating time since quitting and pack-years into smoking status (Model 3)

Variable	Parameter Estimate	Standard Error	Chi-Square	P value	Hazard Ratio	95% CI
Sex	0.66172	0.11252	34.5854	<.0001	1.938	1.555	2.416
Sbp	0.03508	0.00306	131.2240	<.0001	1.036	1.030	1.042
Dbp	-0.04076	0.00621	43.1167	<.0001	0.960	0.948	0.972
Total/HDL ratio	0.22727	0.03592	40.0381	<.0001	1.255	1.170	1.347
Diabetes	0.88176	0.15423	32.6873	<.0001	2.415	1.785	3.268
Trglycerides	-0.00170	0.00059	8.2356	0.0041	0.998	0.997	0.999
Time since quitting
< = 5 years	0.75854	0.18123	17.5189	<.0001	2.135	1.497	3.046
>5 years	0.13762	0.13059	1.1106	0.2920	1.148	0.888	1.482
Pack years
<20	0.15632	0.34319	0.2075	0.6487	1.169	0.597	2.291
20-39	0.50078	0.21593	5.3785	0.0204	1.650	1.081	2.519
40+	0.81008	0.16219	24.9470	<.0001	2.248	1.636	3.089
Test	Total	Event		Censored			% Censored
	3751	383		3368			89.79
	Chi-Square	DF				P value
Likelihood Ratio	324.1494	11				<0.0001
Hosmer Lemeshow	11.4700	9				0.2448
Modified HL	11.0293	9				0.2737
	Estimate	SE				95% CI
C statistic	0.7601	0.0130				0.7346, 0.7856

Note: The reference categories for sex, diabetes and the smoking variable are female, no diabetes and never smoker respectively.

ISSN: 1756-0500