Smoking, smoking cessation, and risk of sudden cardiac death in women

Background: Few prospective studies have examined quantitative cigarette consumption and smoking cessation on sudden cardiac death (SCD) risk with long-term follow-up. Methods and Results: We prospectively examined the association between cigarette smoking and smoking cessation on the risk of SCD among 101 018 women participating in the Nurses' Health Study without known coronary heart disease, stroke, and cancer at baseline 1980. During 30 years of follow-up, we identified 351 SCD events. Compared with never smokers, current smokers had a 2.44-fold (95% CI, 1.80-3.31) increased risk of SCD after controlling for coronary risk factors. In multivariable analyses, quantity of cigarettes smoked daily (P value for trend, <0.0001) and smoking duration (P value for trend, <0.0001) were linearly associated with SCD risk among current smokers. Small-to-moderate amounts of cigarette consumption (1-14 per day) were associated with a significant 1.84-fold (95% CI, 1.16-2.92) increase in SCD risk and every 5 years of continued smoking was associated with an 8% increase in SCD risk (hazard ratio, 1.08; 95% CI, 1.05-1.12; P<0.0001). The SCD risk linearly decreased over time after quitting and was equivalent to that of a never smoker after 20 years of cessation (P value for trend, <0.0001). Conclusions: In this large prospective cohort of women without coronary heart disease at baseline, a strong dose-response relationship between cigarette smoking and SCD risk was observed, and smoking cessation significantly reduced and eventually eliminated excess SCD risk. This suggests efforts to prevent SCD among women should include aggressive strategies for smoking cessation.