The changes in incidence and mortality of stroke and its risk factors were studied in a general population of Hisayama town, where a prospective cohort study was initiated in 1961 (Hisayama study). The characteristics of this study exist 1) 99% of the study subjects had been followed, 2) the development of stroke was completely evaluated by study physicians, and 3) the cause of death was verified by autopsy with average 81% over 40 years. Age and sex-adjusted incidence and mortality of cerebral hemorrhage were markedly and significantly decreased from first cohort (1961-) to second cohort (1974-) and third cohort (1988-). Incidence and mortality of cerebral infarction were halved from the first to the second cohort, but changed little from the second to the third cohort. As for subtypes of cerebral infarction, incidence of lacunar infarction was decreasing, while incidence of atherothrombotic infarction and cardiogenic embolism tended to increase in the recent cohort. As for risk factors, the prevalence of hypertension (≥160/95mmHg) consistently decreased due to increasing of drug treatment and salt restriction. However, the prevalence of metabolic disorders such as glucose intolerance, hypercholesterolemia and obesity continued to increase in recent years, because of westernization of life styple and dietary habits. Changing of incidence and mortality of stroke is apparent in Hisayama population, mainly due to hypertension management, although only less than one-fourth of the hypertensives had been treated appropriately (<140/90mmHg) even in recent years. More strict controlling of hypertension is necessary for further reduction of stroke incidence.
