Relative Familial Clustering of Cerebral Versus Coronary Ischemic Events

BACKGROUND Few population-based studies have ascertained both cerebral and coronary events or considered their relative heritability. Differences in heritability of transient ischemic attack and ischemic stroke versus acute coronary syndromes (ACS) may inform risk prediction, genetic studies, and understanding of disease mechanisms. METHODS AND RESULTS In a population-based study of all acute vascular events, irrespective of age, we studied family history of myocardial infarction (MI), stroke, and related risk factors in first-degree relatives. To allow for differences in rates of affected first-degree relatives caused by differences in disease incidence, we looked at the extent to which parental history was associated with affected siblings within disease category. Nine hundred six probands (604 men; mean age, 70 years) with ACS and 1015 (484 men; mean age, 73 years) with cerebral events had complete family history data. In ACS probands, parental MI was associated with MI in ≥1 sibling (1 parent with MI: odds ratio, 1.48; 1.04 to 2.10; P=0.03; both parents with MI: odds ratio, 5.97; 3.23 to 11.03; P