Epidemiology of stroke among Japanese men in Hawaii during 24 years of follow-up: the Honolulu Heart Program

Abstract

This report present epidemiologic data on stroke incidence and mortality as well as on risk factors for total stroke and subtypes of stroke among Japanese men in Hawaii, who were known to have much lower stroke morbidity and mortality than indigenous Japanese men. Of 7,893 men aged 45 to 68 and free of stroke at baseline examination (1965-68), 587 developed first episodes of stroke during 24 years of follow-up through 1989. Comparing the distribution of stroke subtypes before and after the advent of CT scanning in 1976, there was an increase in thromboembolic stroke (67% to 74%), a decrease in subarachnoid hemorrhage (9% to 6%) and unknown type (7% to 2%), and little change in intracerebral hemorrhage (18% to 19%). Total stroke incidence declined from 5.1 to 2.4 per 1,000 person years between 1969 and 1988, with a mean annual rate of decline of 5%. Total stroke mortality in the target population (examined and nonexamined men combined) also declined markedly, at a rate similar to that reported for U.S. white men of comparable ages. The one-month case fatality ratio fell dramatically in hemorrhagic stroke (75% to 29%) and only slightly (13% to 11%) in thromboembolic stroke during the same period. Relationships between a variety of biological, sociocultural and lifestyle factors and the risk of stroke subtypes were evaluated by means of bivariate and multivariate Cox regression models. Hypertension was the strongest and most consistent risk factor for all subtypes of stroke. Other risk factors showed inconsistent patterns of association with stroke subtypes in multivariate analysis.