Epidemiology of Stroke in a General Japanese Population: The Hisayama Study

The Hisayama Study is an ongoing epidemiological study of stroke, coronary artery disease (CAD), and other noncommunicable diseases in a general Japanese population established in 1961. According to the longitudinal data from the Hisayama Study, average levels of systolic blood pressure among hypertensive individuals have decreased with time since 1961. In contrast, the prevalence of metabolic risk factors such as obesity, hypercholesterolemia, and glucose intolerance has increased with time. The incidence rates of ischemic stroke in this population have declined significantly as a result of improvement in hypertension management, but the proportion of atherothrombotic brain infarction (ATBI) and embolic stroke among the total ischemic stroke cases have increased probably due to the increased prevalence of metabolic risk factors and the increased number of patients with atrial fibrillation (AF) with super-aging population. Therefore, a strategy to reduce the risks of ATBI and embolic stroke by comprehensive management of their risk factors is necessary. In this review, we first show the secular trends in the incidence of stroke and the prevalence of its risk factors using the data from the Hisayama Study. Then, the studies for the association of traditional risk factors with stroke development in the Hisayama Study are introduced. Finally, we developed risk prediction models to estimate the absolute risk of atherosclerotic cardiovascular disease (ASCVD; including ATBI and CAD) and AF, that may be used for the stratification of future risk of ATBI and AF-related stroke in clinical practice or health examination.