Epidemiology of stroke in Japan and comparison with the world

Stroke was the leading cause of death in Japan until 1980s. The results from the Hisayama study, which is a population-based study in Japan, showed that incidence and mortality of stroke decreased with time owing to the improved management of hypertension. Although the incidence of hemorrhagic stroke decreased markedly, the proportion of hemorrhagic stroke among the incident cases of stroke in Japan is higher than in European countries. Among the incident cases of ischemic stroke, the proportion of lacunar infarction decreased significantly, whereas the proportion of atherothrombotic and cardioembolic stroke increased. These changes may be caused by elevating prevalence of metabolic disorders-namely, diabetes and hypercholesterolemia. Effective prevention and management of the metabolic disorder are necessary for further prevention of stroke.