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 of the number attaining the age of 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 the current rates of mortality improvement persist, then it will be as likely for a child born today to reach the age of 100 as it was for a child born eight decades ago to reach the age of 80 (Vaupel and Gowan 1986).

Despite high mortality in the past, China has a large number of elderly people, because the Chinese population is so huge, currently totalling more than 1.25 billion people. The 1990 census reported 6,681 centenarians, 64,532 persons aged 95 or over, 416,134 persons aged 90 or over, and 2.32 million persons aged 85 or over. The annual growth rate of centenarians in China between 1982 and 1990 was 7.1%. The proportion of centenarians is much lower in China than in developed countries. For example, there were between 4 and 5 centenarians per million in China in 1990, while in Denmark there were 80 centenarians per million (Jeune and Kannisto 1997). Consequently, Chinese centenarian research may give us a better understanding of population ageing.

However, the fact that a large number of centenarians was recorded, whether in a census or in an official population register, does not necessarily mean that the country has a large population of centenarians, because elderly people may tend to exaggerate how old they are. Any study on centenarians has to deal with this issue of the age inflation. How good is the data quality on centenarians in China? This chapter attempts to answer this question by presenting a careful validation on age-reporting of Han Chinese centenarians. The next section will give a brief review of the literature on age reporting among centenarians. We will then discuss data resources, methods and results of analyses, which involve comparing information as reported in the Chinese census of 1990 with survey interview data collected by Wang (1996). We will also look at the cultural background of the Chinese, with emphasis on the Han Chinese in particular. As will be shown, the cultural background of people can be an essential tool in the confirmation of age