A 15.5-year cohort study on risk factors for possible myocardial infarction and sudden death within 24 hours in a rural Japanese community.

A 15.5-year follow-up study of ischemic heart disease among residents 40 years and older in a rural community, A-I district, Shibata City, Niigata Prefecture, Japan, was completed in 1992. The response rate for the initial examination was 84.5% of 1,182 men and 92.6% of 1,469 women. Nine hundred and eighty-five men and 1,344 women who were initially free of ischemic heart disease were followed from July 1977 through December 1992. The person-year incidence of possible myocardial infarction (PMI) was 1.01 per 1,000 for men and 0.59 for women, and that of sudden death within 24 hours (24SD) was 1.08 for men and 0.64 for women. In the sex-, and age-stratified univariate analyses by the Cox proportional hazard regression model, statistically significant relative risk of PMI was observed for systolic (SBP), diastolic (DBP) and mean blood pressure (MBP), body mass index and smoking. For 24SD, DBP and albuminuria were selected as significant risk factors. In the multivariate analyses, MBP and smoking were selected as independent risk factors for PMI. No significant association of any factor with 24SD was detected. The influence of serum cholesterol on occurrence of PMI appeared to be subtle.