IV. Subarachnoid Hemorrhage

Abstract

There is a clear difference in the age-standardized incidence of subarachnoid hemorrhages (SAHs) among different countries.1 According to reports, the lowest incidence is 1.04 people/100,000 population/year in the Middle East region,2 and approximately 20 people/100,000 population/year in Finland1 and Japan,3-5 showing a significant variance. Regarding sex, although it has been reported that no particularly consistent gender-related trend is seen on the occurrence of SAH,1 it has also been reported that it was more frequent in women. In Japan, SAHs tend to be more common in women (male-female ratio, 1:2).4 The SAH mortality rate based on a national mortality statistics in the United States is higher for women for all races.6 In Japan, the percentage of SAHs among all cerebrovascular diseases increased as of the late 1980s compared with that in the 1950s.7 The age-adjusted mortality rate remains on the same level for men, whereas it is doubling for women. Recent changes in lifestyle for women are likely to be associated with this,8 so this trend needs to be carefully followed in the future.