Infant, neonatal, postneonatal and perinatal mortality in Spain, 1975-1984. Interregional and interannual differences.

The national infant, neonatal, postneonatal and perinatal mortality in Spain does not reflect the differences which exist among regions. The aim of the present study is to demonstrate and to quantify these differences, as well as their annual trends. We have also attempted to define groups of regions presenting similar rates. The results of the study confirmed a decrease in all mortality rates during the analyzed period. Regions were grouped according to their rates. Differences between the top and the bottom groups (with the lowest and the highest rates, respectively) resulted in statistical significance. However, the differences between these and the middle groups were not sharply defined. In addition, a clear geographic aggregation was evidenced in both top and bottom groups. These differences are mainly due to economic and sanitary factors.