Age validation of centenarians and gathering data about the
demographic patterns and health status of centenarians have become a
research area of importance because populations in most countries are aging.
China’s population, in particular, is aging at an extraordinarily rapid rate
(Banister, 1990; Ogawa, 1988; Zeng and Vaupel, 1989). Centenarians used to
be exceedingly rare. They are still rare today, but the number of centenarians
is now doubling approximately every decade (Kannisto 1994, Vaupel and
Jeune 1995). The average annual growth rates in the 1970s and 1980s in the
number attaining age 100 were, for example, 10.2%, 9.2%, and 9.1% in Japan,
Switzerland, and West Germany respectively (Vaupel and Jeune, 1995, p.
112). If current rates of mortality improvement persist, then it will be as likely
for a child born today to reach age 100 as it was for a child born eight decades
ago to reach age 80 (Vaupel and Gowan, 1986).