Table 3.

Stratified analysis for the association of smoking habit change on cardiovascular disease according to subgroups of aspirin or warfarin use

		Adjusted hazard ratio (95% confidence interval)a
		Continual smokers	Quitters	Sustained ex-smokers	Never smokers	p for trend
Cardiovascular disease	Aspirin use
	No	1.00 (reference)	0.59 (0.31–1.13)	0.55 (0.34–0.90)	0.55 (0.35–0.86)	0.013
	Yes	1.00 (reference)	0.70 (0.42–1.16)	0.94 (0.65–1.35)	0.80 (0.56–1.14)	0.361
	Warfarin use
	No	1.00 (reference)	0.66 (0.43–1.03)	0.71 (0.51–0.98)	0.73 (0.54–0.99)	0.073
	Yes	1.00 (reference)	0.45 (0.18–1.13)	0.85 (0.45–1.61)	0.52 (0.28–0.97)	0.088
Total stroke	Aspirin use
	No	1.00 (reference)	0.63 (0.26–1.54)	0.44 (0.21–0.91)	0.71 (0.38–1.31)	0.269
	Yes	1.00 (reference)	0.83 (0.40–1.69)	1.04 (0.61–1.77)	0.79 (0.47–1.33)	0.423
	Warfarin use
	No	1.00 (reference)	0.70 (0.38–1.29)	0.74 (0.46–1.16)	0.78 (0.51–1.20)	0.343
	Yes	1.00 (reference)	0.64 (0.17–2.46)	0.85 (0.31–2.35)	0.54 (0.20–1.49)	0.255
Coronary heart disease	Aspirin use
	No	1.00 (reference)	0.53 (0.22–1.29)	0.60 (0.31–1.14)	0.46 (0.25–0.84)	0.018
	Yes	1.00 (reference)	0.62 (0.32–1.19)	0.87 (0.55–1.38)	0.83 (0.54–1.29)	0.661
	Warfarin use
	No	1.00 (reference)	0.64 (0.36–1.15)	0.68 (0.44–1.04)	0.74 (0.50–1.10)	0.197
	Yes	1.00 (reference)	0.32 (0.10–1.03)	0.67 (0.32–1.42)	0.41 (0.20–0.86)	0.053

^aHazard ratios calculated by Cox proportional hazards regression analysis after adjustments for age, household income, alcohol consumption, physical exercise, body mass index, systolic blood pressure, fasting serum glucose, total cholesterol, Charlson comorbidity index, aspirin use, warfarin use, and index year