Patients with myocardial infarction constituted 2.36% of all the hospitalized patients during 1961-1968. The mortality of the hospitalized patients with myocardial infarction during the same term was 19.1%. The ratio of the male to female patients with myocardial infarction was 5.2. 2) As the risk factors of myocardial infarction, the following items were considered to be of importance: 1. gout in past history, 2. angina pectoris in family history, 3. diabetes mellitus in family history, 4. cigaret smoking over 40 pieces per day, 5. diabetes mellitus in past history, 6. administrative occupation, 7. serum cholesterol level over 250 mg/100 ml, 8. obesity of 20% excess over standard body weight, 9. hypertension in family history. 3) According to the statistical analysis, several groups of risk factors and interrelationship of risk factors are recognized.
