Determination of the Association Between Smoking and Recurrence of Ischemic Stroke using a Competing

Objective To determine the association between smoking and ischemic stroke recurrence. Methods We conducted a prospective follow-up study of patients with first incidence of stroke. A competing risks model was used to establish the association between smoking and stroke recurrence. Results A total of 594 stroke patients were recruited. Among the 361 male patients, 59 recurrent events and 13 competing events occurred. Among the 233 female patients (all were non-smokers), 49 recurrent events and 11 competing events occurred. Adjusted for confounding factors, male nonsmokers exposed to passive smoking had a SHR of 3.040 in comparison with those without exposure to smoking and the P value was borderline significant. Those who smoked 100-200 cigarettes a year had a SHR of 0.947. The other groups with exposure to smoking had a greater than 1 SHR, but without statistical significance. Moreover, no significant associations between recurrence of ischemic stroke and smoking index/cumulative smoking were found. The female nonsmokers who had exposure to passive smoking only at follow-ups had a SHR of 1.4 （and all other groups had less than 1 SHR）. But no statistical significances were found in the comparisons. Conclusion Further research with a larger sample size is needed to establish the association between smoking and recurrence of ischemic stroke.