RT Journal Article SR Electronic T1 P58 Understanding pathways to inequalities in child mortality: a mediation analysis using whole population linked data in Wales JF Journal of Epidemiology and Community Health JO J Epidemiol Community Health FD BMJ Publishing Group Ltd SP A68 OP A68 DO 10.1136/jech-2021-SSMabstracts.146 VO 75 IS Suppl 1 A1 Daniela Schlueter A1 Eric Lai A1 Hoda Abbasizanjani A1 Rowena Griffiths A1 Ashley Akbari A1 David Taylor-Robinson YR 2021 UL http://jech.bmj.com/content/75/Suppl_1/A68.2.abstract AB Background There has been an unprecedented rise in infant mortality rates in the UK since 2014, especially in disadvantaged areas. This trend is concerning since infant mortality is a sensitive indicator of the prevailing social conditions affecting health across the life course. Identifying potentially modifiable factors on the pathway linking childhood socio-economic conditions (SECs) to child mortality is important to inform public health policies to reduce health inequalities. The aim of this study was to assess the extent to which intervening on maternal health, perinatal factors and/or birth outcomes might reduce inequalities in child mortality.Methods We conducted a causal analysis of linked population level data from the SAIL Databank on all singletons born in Wales between 2000 and 2019 and their mothers. The exposure of interest was mother’s quintile of small area deprivation 3-years prior to pregnancy; the outcome was child mortality between birth and age 15-years. The data included gestational age, birthweight, parity, maternal age, maternal health conditions before and during pregnancy, pregnancy complications, congenital anomalies, smoking during pregnancy and perinatal maternal mental health. Using the framework of interventional disparity measures, we estimated the contribution of factors relating to maternal health, perinatal factors and birth outcomes to inequalities in child mortality adjusting for potential confounding by parity. Confidence intervals will be calculated by non-parametric bootstrap.Results There were 763,241 singleton live births in Wales between 2000 and 2019 and of these, 3,289 children died within the first 15 years of life. Initial results are based on a complete-case analysis of data on 463,200 births out of which 1,719 died by age 15. The probability to have died by age 15 was 1.37 times as high in the most deprived quintile compared to the least. After shifting the distribution of maternal health, perinatal factors and birth outcomes in the most deprived population quintile to that in the least deprived quintile, the survival probability ratio between the most and least deprived children was reduced to 1.09.Conclusion Child mortality is a rare event but with clear socio-economic patterning. Initial results indicate that maternal health, perinatal factors and birth outcomes may explain most of the observed inequalities. Further analyses will aim to disentangle the contribution of these mediating blocks to identify potential public health policy entry points.