[Direct mail investigation of the social and physical background of centenarians in Tokyo metropolitan area].

This study was designed for the purpose of investigating the factors for longevity in the Tokyo metropolitan area. At first, we examined the social and physical background of centenarians by direct mail in 1992. A total of 398 questionnaires (from 81 males and 308 females) were returned. There was a significant gender difference in mobility, with 38% of males and 10% of females being able to take a walk. However 19% of male centenarians and 28% of female ones were bedridden. Hypertension, respiratory disease and heart disease were found in 22%, 16%, 16%, without any significant gender differences. On the contrary, there were more female centenarians with past histories of bone fracture (34%) than male (10%). This discrepancy suggest that bone fracture may be one of the factors causing the gender differences in mobility. Those who had a high level of education were more frequent in centenarians (27% of males and 8% of females) than in the general population of their contemporaries in Japan (less than 2%). The average age at death of the centenarians' parents was 69.6 +/- 15.7 y/o for their father and 71.2 +/- 17.2 y/o for their mother. These ages were significantly higher than the average life-span in the last decade of the 19th century, according to the First Life Tables in Japan. The possibility is suggested that longevity was inherited in these centenarians' families.