Cerebrovascular diseases in a fixed population of Hiroshima and Nagasaki, with special reference to relationship between type and risk factors.

A study was made of the incidence of cerebrovascular disease, the chronological trends, and the relationship between the disease types and risk factors in 16,491 citizens of Hiroshima and Nagasaki. The subjects underwent medical examination at least once between 1958-74, and were free of cerebrovascular disease at the initial examination. During the 16-year period, 1.162 cases of cerebrovascular disease developed in the study population, with diagnosis definite in 621. By type, there were 108 cases of cerebral hemorrhage, 469 cases of cerebral infarction, 33 cases of subarachnoid hemorrhage, and 11 cases of other unclassifiable types. As a risk factor of cerebral hemorrhage, elevation of systolic and diastolic blood pressure was the most closely related to onset, and left ventricular hypertrophy on electrocardiogram (ECG), and proteinuria were also related. However, a tendency was seen for the risk to be higher when the levels of serum cholesterol were lower. In cerebral infarction, aging like systolic blood pressure, was a most important risk factor. Left ventricular hypertrophy on ECG, proteinuria, and diabetes could also be risk factors. However, the relation to blood pressure, especially diastolic blood pressure, was not so great as in the case of cerebral hemorrhage.