I. Stroke in general.

Stroke is the third most common cause of death following cancer and cardiac diseases in Japanese people. This order has not changed since 1980. However, because stroke is the most common disease leading to a bedridden state and its incidence is 3to 10-fold higher than that of myocardial infarction, there is no doubt that the prevention and treatment of stroke are important in Japan. Compared with Western countries, stroke may be more frequent in Japan due to differences in dietary habit such as higher salt intake and lower fat intake. The daily salt intake for Japanese people is around 12 g and is obviously higher than that for American people. Excessive salt intake is related to hypertension which is the greatest risk factor for stroke. In particular, salt sensitive hypertension is profoundly related to nocturnal hypertension, and may have a high risk of stroke. Nonetheless, non–salt-sensitive hypertension is somewhat more frequent than salt sensitive hypertension