IS FAMILY HISTORY AN INDEPENDENT RISK FACTOR FOR STROKE

Objective--To estimate the influence of family history on the occurren ce of stroke. Methods--A case-control study was carried out from Augus t 1992 to January 1994. The study population comprised 502 patients wi th a first stroke, aged between 20 and 70 years, who were treated at 4 8 affiliated hospitals. The same number of age and sex matched control s were selected from outpatients. Diagnoses were based on CT findings and clinical signs. There were 155 case-control pairs for subarachnoid haemorrhage, 158 for intracerebral haematoma, and 159 for cerebral in farction. Information about the patients and their families was obtain ed from a questionnaire which included the family histories of each su btype of stroke and other potential risk factors for stroke. The data were analysed focusing on the role of the family histories in the occu rrence of stroke. Results--In univariate analysis, the family historie s of subarachnoid haemorrhage and intracerebral haematoma were positiv ely associated with each of the subtypes of stroke (odds ratios 11.24 for subarachnoid haemorrhage, 2.39 for intracerebral haematoma), where as family history of cerebral infarction was not a significant risk fa ctor for its occurrence (odds ratio 1.41). Family history of intracere bral haematoma was correlated with a personal history of hypertension and habitual alcohol consumption. After adjustment for potential risk factors (hypertension, diabetes, hyperlipidaemia, obesity, alcohol con sumption, and regular smoking), family history of subarachnoid haemorr hage still remained the most powerful risk factor for subarachnoid hae morrhage, whereas family history of intracerebral haematoma no longer showed a significant association with haematoma. Conclusion--Genetic f actors play a major part in the pathogenesis of subarachnoid intracere bral haematoma via certain hereditary components such as hypertension, and even lifestyle factors such as alcohol consumption. In cerebral i nfarction, genetic factors play a minor part in its pathogenesis.