Epidemiologic studies of coronary heart disease and stroke in Japanese men living in Japan, Hawaii and California: incidence of stroke in Japan and Hawaii.

Abstract

As part of the Ni-Hon-San Study, stroke incidence was compared in the Japan and Hawaii cohorts. Stroke cases were classified in 2 types, intracranial hemorrhage (ICH) and thromboembolic stroke (T-E). For each type the incidence in Japan was about 3 times as great as in Hawaii. The ratio ICH/T-E was 1/2.2 and 1/1.6 in Japan and Hawaii, respectively. Blood pressure was the most important risk factor, followed by age for total stroke in both Japan and Hawaii. Proteinuria was also a risk factor in Hawaii. Conversely, an index of animal food intake was inversely related to total stroke, significantly in Hawaii, and at a suggestive level for total and hemorrhagic stroke in Japan. Since the levels of blood pressure do not differ between Japan and Hawaii, 1 possible explanation for the large difference in stroke incidence between the 2 cohorts may be the fact that animal protein and saturated fat intake, which is inversely associated with stroke incidence, is much greater in Hawaii than in Japan. This explanation would support epidemiologic and experimental studies in Japan which suggest that dietary animal protein and fat exert an inhibitory effect on the incidence of stroke.