Three decades of inequality in neonatal and early childhood mortality in singleton births in Scotland.

Background: Socioeconomic inequality in child mortality highlights opportunities for policies to reduce child deaths.

Methods: We used singleton birth, death and maternity records from Scotland, 1981-2011, to examine mortality rate differences by age across deprivation quintiles over time. We measured the difference between the most and least deprived quintiles (Q5-Q1) and the slope index of inequality (SII) across all quintiles-measures of the absolute deprivation gap, providing an indication of the public health impact.

Results: Q5-Q1 remained relatively constant from 1990 onwards for early neonates, widened in the mid-2000s for late neonates, increased in the 1990 s then decreased in the 2000 s in the post-neonates and declined over time in early childhood. The trend over time in SII showed no significant change for early neonates (P = 0.440), significant decrease for post-neonates (P = 0.010) and early childhood (P = 0.043), and significant increase for late neonates (P = 0.011).

Conclusions: Over three decades, the absolute deprivation gap in mortality widened in late neonates but stabilized or declined at other ages. This may reflect improved survival beyond the early neonatal period of babies with conditions related to socioeconomic inequality such as prematurity. Monitoring birth cohort data could enhance understanding of this vulnerable group.