Worldwide demography of centenarians.

The global number of centenarians should strongly increase during the 21 st century. According to the Population Division of the United Nations it should reach more than 25 million people in 2100. To better understand the dynamics of the emergence and growth of the centenarian population, we focused on four European countries having long chronological series and high quality data about centenarians, Denmark, France, Sweden, and Switzerland, and Japan which has had the highest life expectancy at birth for several years. we analysed the emergence of the centenarian populations and their pace of growth in the wider context of the adult longevity revolution, as well as the trends in mortality level among these new populations. We found that out of the 5 countries studied, the decrease in mortality at age 100 for females who are leading the adult longevity revolution, seems to be interrupted in 4 countries, including in Japan. These results are in favour of the scenario of "compression of mortality", possibly limiting the future number of centenarians. However, previous studies have shown that demographic transitions are not linear and, after periods of interruption, trends can resume towards an always greater longevity.