Abstract
Risk factors involved in the occurrence and progress of stroke are considered to be multiple, but are not yet clearly identified. Among the causes of death, stroke is still in the third position after cancer and cardiovascular diseases. The incidence of stroke is relatively high in Japan, compared with that in Western countries. We investigated risk factors of stroke by using 122 patients, consisting of 91 males and 31 females (mean age of 63.7±12.3 years), who were hospitalized due to stroke at Okayama National Hospital during the period of January 1985 to June 1987.
The cause of stroke was TIA in 8.2% of the patients, cerebral thrombosis in 39.3%, cerebral embolism in 5.7%, and cerebral hemorrhage in 46.7%. The lesion was detected in the internal carotid artery in 11.8% of the patients with cerebral infarction, in the cortical branch in 58.8%, in the perforating branch in 15.7%, in the cerebellum in 8.8%, and in the pons in 7.8%. Cerebral hemorrhage was found in the cortical branch in 21.2%, in the perforating branch in 54.4%, in the cerebellum in 8.8%, in the pons in 10.5% and in the cerebral ventricle in 3.5%. The incidence of stroke did not change with the seasons.
In cerebral infarction, hypertension and smoking were risk factors. In cerebral hemorrhage, alcohol drinking and high blood sugar levels on admission were found as risk factors. The primary vascular lesion was atherosclerosis in the cortical branch and was arterionecrosis in the perforating branch. Risk factor analysis was made separately in these two cases by discriminant function method. In the former case, cerebral infarction was related to smoking and cerebral hemorrhage was related to alcohol drinking and high blood sugar levels on admission. In the latter case, however, no such risk factors related to infarction and hemorrhage were noted. Analysis on risk factors in the responsible vessels revealed that hypertension was a risk factor in the perforating branch, but there was no risk factor in the cortical branch. Alcohol drinking and smoking seemed to be risky for the vertebrobasilary artery.
