34 巻 (1976) 4 号 p. 163-172
In Japan, districts of longevity have become the object of academic study since 1950. However, owing to the recent economic developement, the population and habits in these areas have been drastically changed. Moreover, in 1975, average life expectancy of Japanese people reached 71.76 (male) and 76.95 (female) years old. Thus, it became necessary to survey these districts in mountains, rice fields, isolated islands and seasides. The age of all centenarians in the areas was confirmed by the official birth record (Koseki). Population of old men and women in each area in Feburuary 1976 was listed. Most of the islands and seasides were visited during June, 1976. The results were as follows:
1. In every area except Nishinoshima (Shimane), Ishii and Aizumi (both are close to Tokushima city), the percent of inhabitants over seventy years of age has been increased since 1950 (Table 1). The highest figures (male 12.1%, female 19.6%) were observed in Ohgimison (Okinawa) as contrasted with 3.9% (male) and 5.3% (female) of the average Japanese (Table 2). The emigration of young population (maximum 30% per 5 years) was observed in every area except Ishii and Aizumi (Table 3).
2. The percent of inhabitants over ninety years of age was 0.19 (male) and 0.23 (female) in the mountains, 0.06 and 0.20 in the rice fields, 0.24 and 0.72 in the islands and 0.25 and 0.61 in the seasides. Ohgimison had the highest figures (male 0.4%, female, 1.3%) with population of 4, 126 including four centenarians. The eldest person in Japan was 112 years old. Most of these old people in the areas were hypertensive and their diet habits in their youth were characteristic to each area (Table 4). Otherwise, their case histories were similar to the reports on average Japanese centenarians (1975, male 157, female 651), and they had long-lived parents or close relatives.
3. The diet and life style of these old people (Table 4) and all inhabitants (Table 3) in these areas have changed completely. Instead of barley (most of the area) or sweet potatoes (Okinawa) taken in the past, rice became the major diet in every area. Characteristic diet in each area was lost except Okinawa. Of all working population in these areas, percentage of fishermen and foresters decreased (20 to 60%). Ten out of sixteen areas became resorts.