Incidence of ischaemic and haemorrhagic stroke and the association with smoking and smoking cessation: a 10-year multicentre prospective study in China.

ABSTRACT

OBJECTIVES: To examine the effects of cigarette smoking and smoking cessation on the incidence of ischaemic and haemorrhagic stroke in a multicentre prospective cohort study among Chinese. STUDY DESIGN: A multicentre population-based prospective cohort study. METHODS: The incidence of, and deaths from, stroke were monitored among 26,607 participants (12,560 men and 14,047 women) who were enrolled in 1986 and free from stroke until 2000. Cox's proportional hazard model was performed to obtain the hazard ratio (HR) of cigarette smoking for stroke risk after adjustment for major confounders. RESULTS: After an average of 9.5 years of follow-up, 1108 subjects developed stroke. The excess risk of all types of stroke (total stroke) among male current smokers [HR 1.39, 95% confidence interval (CI) 1.15-1.67] was mainly due to a significantly elevated risk of ischaemic stroke (HR 1.49, 95% CI 1.17-1.90). A significantly increased risk for total stroke and ischaemic stroke was observed among men who smoked >15 cigarettes/day and men who had smoked for >25 years. The rate of smoking cessation was very low among Chinese men (7.2%) and women (1.5%). Smoking cessation did not appear to reduce the risk of haemorrhagic stroke, but may reduce the risk of ischaemic stroke; however, the possibility that this result was due to chance cannot be excluded (HR 0.74, 95% CI 0.26-2.08). CONCLUSION: This study confirmed that cigarette smoking is a major determinant for the incidence of ischaemic and haemorrhagic stroke in Chinese men, and emphasizes the need for improved strategies to help people quit smoking.