Aggregation of multiple risk factors for stroke in siblings of patients with brain infarction and transient ischemic attacks.

Hypertension, heart disease, and diabetes are not only the major risk factors for stroke, but they tend to cluster in families. It is unknown, however, whether these conditions occur more frequently among relatives of patients with specific types of stroke as compared to non-relatives. The frequencies of stroke and its major risk factors in two groups of subjects were compared. One group consisted of 76 siblings of 41 patients hospitalized with cerebral infarction and transient ischemic attacks in an investigative stroke unit; the other consisted of 55 siblings of the patients' spouses. The occurrence of these conditions in the relatives was determined from a questionnaire completed by the relatives and supported by information from the relatives' family physicians. When considered separately, hypertension, heart disease, and stroke occurred in a small but not statistically significant excess among the relatives in-law. However, various combinations of two or three diseases, (including diabetes), occurred in 20.9% of the patients' siblings as compared to only 3.6% of the relatives in-law (p less than 0.001). These results suggest that living siblings of patients with cerebral infarction and transient ischemic attacks may have an increased risk of stroke and cardiovascular disease as a result of multiple risk factors operating simultaneously. Prevention programs among this high risk population may be particularly worthwhile.