Cohort analysis of gender gap after one hundred years old: the role of differential migration and survival trajectories

The persistence of mortality decline at all ages, and particularly at older ages, means that an increasing number of individuals are becoming centenarians and semi-super centenarians. Our hypothesis is that the gender differences in mortality level in old ages had an impact on the number of men and women reaching 100 years and so on the gender gap. Work-related international migration was also an important characteristic of Italian cohorts born in the last decades of the Nineteenth century, and in the first decades of the Twentieth, as these migrations affected more men than women. Referring to the Istat (Italian National Institute of Statistics) mortality data (Cause of Death Survey and Deaths of Resident Population survey) and the Semi super and Super centenarians Surve -SSC, that has been realized by Istat since 2009, the aim of this paper is to present the development of the gender gap for the cohorts born between 1870 and 1912 beyond 100 and 105 years old. We have confirmed our hypothesis, explaining the characteristics of this development on the basis of estimates of the role played by the different migratory histories of the two genders and, above all, by the differences in the male and female survival trajectories of the cohorts in the study.