[Incidence rate of acute myocardial infarction in Hokkaido, Japan].

ABSTRACT

A survey of acute myocardial infarctions (AMI) that occurred from October 1990 through September 1993 in Obihiro City, Hokkaido, was conducted. A total of 114 new cases of AMI was registered over the 3-year period. The incidence rate of AMI was 33.4 cases per 100,000 men per year and 137 cases per 100,000 women per year (total, 23.2 cases). The mean age at which AMI occurred was 11 years higher in women (71.1 +/- 9.4 years) than in men (60.0 +/- 11.8 years). In men, AMI was most common during the eighth decade of life, while in women the incidence of AMI increased after menopause. The ratio of cases of AMI to cases of stroke in the same period was 14.5. These results did not differ from the results of other surveys done over the same period in seven other area of Japan. To study risk factors for myocardial infarction, the data were grouped according to the results of medical examinations. Hypertension, diabetes, obesity and smoking were common among people with AMI. The incidence rate of hypercholesterolemia did not differ between those with AMI and those without, and only a relatively small number of people with AMI drank alcohol. Past reports have pointed out changes in the 'structure' of cardiovascular disease in Japan, which have accompanied changes in diet and lifestyle. This study has shows that aging hypertension, diabetes, obesity, and smoking are risk factors for myocardial infarction. Proper management, including early detection of these factors, will help to prevent of ischemic heart disease in Japan.