FAMILIAL AGGREGATION OF STROKE - THE FRAMINGHAM-STUDY

Background and Purpose: Family history is perceived to be an important risk factor for stroke despite conflicting published data. We examine d patterns of familial aggregation of stroke among three generations u sing data from the Framingham Study. Methods: Cox proportional hazards analyses, adjusting for known stroke risk factors, were used to exami ne familial concordance in three groups: (1) members of the original F ramingham cohort using reported parental stroke death; (2) members of the Framingham Offspring Study and their parents (members of the origi nal Framingham Study); and (3) sibships within the original Framingham cohort. Results: We found no association between stroke or transient ischemic attack among original cohort members and their reported paren tal stroke death (n=4933; relative risk [RR]=1.07). Using verified cas es of parental stroke or transient ischemic attack, the Offspring anal yses revealed that both paternal (n=1762; RR=2.4; 95% confidence inter val [CI], 0.96 to 6.03) and maternal (n=2074; RR=1.4; 95% CI, 0.60 to 3.25) histories were associated with an increased risk. Parental histo ry of coronary heart disease was strongly associated with stroke or tr ansient ischemic attack among Offspring Study members (RR=3.33; 95% CI , 1.27 to 8.72). Sibling history of stroke or transient ischemic attac k was not associated with stroke or transient ischemic attack among or iginal cohort members, although a non-statistically significant increa sed risk associated with sibling history of atherothrombotic brain inf arction was observed (RR=1.8; 95% CI, 0.68 to 4.94). Conclusions: Thes e analyses suggest that parental history of stroke may be a risk facto r for stroke. As more stroke or transient ischemic attack events devel op among the Offspring Study members, it will be valuable to reexamine these associations.