[Geographical epidemiologic studies on factors associated with centenarians in Japan]

To explore factors associated with longevity, we studied geographic distribution of centenarians in Japan, based on 1990 the population census. We calculated the proportion of centenarians from ratio of number of centenarian to that of population aged 65 years or older. Centenarians in Japan consisted of number 4,152 persons. By prefecture, Tokyo had the most centenarians (383), followed by Okinawa (193) and Fukuoka (151) prefectures. Fukui had the least (24), followed by Akita (26) and Ishikawa (29) prefectures. The proportion of centenarians in Japan was 21.6 (per 100,000 populations) in 1990. By prefecture, the highest proportion lived in Okinawa (133.8), whereas the fewest were found in Akita (8.9). The relationship between geographic distribution of centenarians and environmental factors and nutritional factors were analyzed. Correlation coefficients between proportion of centenarians and mean temperature, high quality of welfare work and of medical services, and having much leisure time were positively significant. As for nutritional factor, correlation coefficients between proportion of centenarians and protein (% of energy) was positively significant, while intake of total energy was negatively significant.