The association of stroke and family history of stroke depends on its subtypes and gender: A family history study in Taiwan

Objective: Family history is a risk factor for stroke. The objective of this study was to investigate whether stroke subtypes and gender might have a familial contribution to stroke. Methods: Detailed family history analysis was used to investigate the parents or siblings of the probands and controls who were classified into 3 groups: probands, outpatient controls, and spouse controls. The lifetime risk (LTR) of stroke was estimated using a Cox proportional hazard model. Results: The 684 probands and controls yielded 1066 parents and 3247 siblings. Compared to the parents and siblings of the controls, those of the stroke patients had a significantly higher LTR. The findings were consistent between probands with cerebral infarction (CI) or cerebral hemorrhage (CH), independent of diabetes, hypertension, and smoking. With regard to gender, family history of stroke was significant for both parents and siblings of the CH or CI patients, but not for the fathers of CI patients and sisters of CH patients. The family history of stroke was associated with an increased risk of stroke of all subtypes, except cardioembolism. Conclusions: This study supported the familial contribution to stroke in the case of both CI and CH but not cardioembolism, independent of the established risk factors for stroke. Gender differences in familial clustering of stroke subtypes were also revealed. These results warrant further molecular genetic studies.