The population with life insurance by the organization amounted about to 18 millions in 1985. The incidence of stroke death was 0.36‰ in 1984 and 0.35‰ in 1985. The latter figure was corrected to the national population to ae 0.92‰(national stroke death 1.12‰). Stroke mortality was strongly dependent on the age. Sex differences were larger at 40 to 60 years of age and approach to 1.0 in the group over 70 years of age. According to the description on the death certificate, which was available in 4, 147 cases, the incidence of cerebral bleeding was 41%, cerebral thrombosis or embolism 27% and subarachnoidal hemorrhage 19%. Thirty percent of cases died within 24 hours from the onset of attacks and 25% within 1 month. Early death was frequent in cerebral hemorrhage and in younger cases. Out of 4, 147 cases above, 1, 655 cases had medical examination at the entry. They showed lower mortality rate than the corresponding age group of those without madical examination. Cases with high blood pressure at the entry showed shorter survival period and higher incidence of cerebral hemorrhage.

Cerebral stroke in rural areas is a very important disease both from medical and social aspects. Among strokes, infarction which occurs most frequently in elderly persons is liable to result from atherosclerosis. And for the development of atherosclerosis, essential hypertension is the most important predisposing factor. Other than hypertension, aging, diabetes mellitus, hyperlipemia, esp. low HDL/Tch ratio, increased hematocrit values, coronary insufficiency, cardiac failure, arythmia, esp. atrial fibrillation, are also accepted important risk factors. Affirmative of such findings, the authors are convinced of the fact that atrial fibrillation which is increasing recently is closely related to both cerebral thrombosis and embolism.
But, in regard to cerebral infarction no signifying or trigger factor, similar to very high blood pressure, that trigger cerebral hemorrhage, is clarified as yet. It is made clear in this connection that cardiac failure predisposed by hypertensive heart disease in old age, assisted by pathophysiological and other environmental conditions, is the important factor. The authors also studied the clinical predisposing parameters and preventive measures about strokes.

Cerebrovascular disease is still considered a serious health problem in Japanese rural areas. The rate of death from the disease is very high. Many clinical and epidemiological studies have been conducted so far. However, they have failed to come up with answers effective for prediction and prevention of the scourge.
As part of the agricultural coop commissioned research project entitled “Study of Cerebral Apoplexy: Its Prediction and Prevention, ” we took a questionnaire survey in 1985-86, to obtain data as regards patients' subjective symptoms, electrocardiographic observations, hematological findings and many others before the onset of cerebral apoplexy. Five medical research institutes affiliated with the national welfare federation of agricultural cooperatives responded to our questionnaire.
As a result, the subjective symptoms that showed stochastically significant increases from one year to three months before the onset of the disease as a whole were fatigue, forgetfulness and insomnia. When it comes to cerebrovascular infarction, shortness of breath, angina, forgetfulness, and nocturia were particularly notable.
All these symptoms are not peculiar to cerebral apoplexy, but it should be noted that these are the warning signals of the killer disease.