Relationships between early mortality and sex ratio: changes over the last century in Italy

Italy, like other industrialized countries, experienced during the last century a dramatic change in socio-economic conditions and in sanitation. In order to ascertain whether the improvement in living conditions has modified the relationships between the sex ratio at birth and selection by early mortality (stillbirth, mortality up to 1 month, mortality up to 1 year of life), the secular trends of the sex ratio in total births, in survivors up to 1 month and up to 1 year of age have been calculated for the Italian population over the last century. The results can be summarized as follows: (i) the sex ratio in total births progressively decreases; (ii) the sex ratio in survivors up to 1 year progressively increases. As a result of these two opposite trends, the difference between sex ratio at birth and after the incidence of early mortality is progressively getting smaller.