Stroke trends in Japan.

In Japan, stroke now ranks third among all causes of death following cancer and heart disease. Stroke was the leading cause of death for 3 decades after 1951. Stroke mortality tended to increase until about 1970, but it decreased and yielded first place to cancer in 1981. Heart disease deaths outnumbered stroke deaths beginning in 1985. There have not been any nationwide studies of stroke incidence in Japan, but results of studies in model areas such as Akita/Osaka, Nagano, Hiroshima/Nagasaki, and Hisayama show remarkable decreases in the incidence of cerebral infarction and cerebral hemorrhage. However, the decrease in cerebral infarction is less, especially at advanced ages where the frequency of disability is still high, and a major problem. There have not been any nationwide studies of survival rates after stroke either. In the Hiroshima/Nagasaki Study, the cumulative survival rates of cerebral hemorrhage and cerebral infarction improved from 1958 to 1969 to the period from 1970 to 1984. The decreasing incidence and mortality rates of stroke and the improving survival rate may be explained by the trends toward less severe strokes and improved medical service; however, the most influential factors are considered to be adoption of a less traditional life-style and improved blood pressure management throughout Japan.