Emergence of oldest old and centenarians: demographic analysis

The number of centenarians is increasing in most countries (including the developing countries). The numbers of centenarians and the corresponding growth rates in different countries are compared. Although there may be biases related to migration, there are large differences between countries in terms of the numbers of centenarians (Japan being highest, followed by France). Three components that could explain the increase in the numbers of centenarians were investigated, namely: the number of newborns a century ago, their survival up to age 100 years, and survival of the centenarians themselves. The most important factor was improved survival between age 80 and 100 years. The 2010 United Nations World Population Prospects estimate that the worldwide number of centenarians will continue to increase, more so in today’s developing countries, particularly in the second part of the 21st century. Accordingly, farreaching economic and social adjustments will become necessary to meet the growing needs of care for these oldest old.