Supercentenarians in Japan

Abstract

Abstract. This chapter provides an overview of two registration systems, the Family Register "Koseki" and the Registry Registration System, which are the basis of age validation in Japan. Data sources for centenarians and supercentenarians are described and the reliability of the information on birth and death is discussed. The chapter explains how we validated the ages of the persons studied and presents trends in the highest ages and the number of supercentenarians in Japan.

The Blue Zones: areas of exceptional longevity around the world

“…In Okinawa, as elsewhere in Japan, the individual validation of age is based on the koseki, a family register containing records of all members of a family, including gender, dates and places of birth, names of parents, dates of marriage and divorce if any, date and place of death (Saito 2010). Unfortunately, for privacy reasons, data extracted from the koseki such as birth and death records are only accessible by directly asking the relatives of the concerned persons or for official legal proceedings (Willcox et al 2008).…”

Exceptional Longevity in Okinawa:

“…Validating population longevity requires several types of demographic analysis, as well as verification of the accuracy of the demographic data. Saito (2010) has confirmed that individual age validation of the oldest olds in Japan is quite difficult because of limited access to original data sources. Certificates of residence (Juminahyo) may be obtained quite easily, but these are secondary sources that do not provide enough information for age validation purposes, and, furthermore, such data can be discarded five years after death.…”

“…It presents a battery of arguments that support the conclusion that the high prevalence of centenarians in Okinawa is valid and warrants further study of its genetic and environmental correlates. The present article intends to revisit these arguments, to assess the demographic aspects of the longevity of the population of Okinawa, and also to consider recent research by Saito (2010) on the age validation of super-centenarians in Japan.…”

The mystery of Japan's missing centenarians explained

“…(For a full discussion, see Saito (Saito 2010). The first source is the Family Registration System (Koseki), which was started in 1872.…”

“…The demographic information for all members of a given household, including the address registered in the family register, date of birth, date of death, relationship to the household head, and previous residential addresses, is recorded on a resident's card (Jyumin-hyo). The difference between a Family Register and a Resident Register is that information included in the latter is current and cannot be used to trace family lineage (Saito 2010). Changes in a Resident Register, such as the birth or death of a household member, are supposed to be reflected automatically in a Family Register.…”