DECOMPOSITION OF CHANGES IN UNDER-FIVE MORTALITY IN NIGERIA GEO-POLITICAL REGIONS

Abstract

Despite global decline in childhood mortality, public literature still indicates that child health outcomes are generally poor in Sub-Saharan Africa. India and Nigeria account for more than a third of all under-five mortality. The progress in lowering child mortality has been paralleled by progress in various determinants of health such as poverty reduction, improved health technologies, and quality education. There are gaps in evidence that capture if the decline in child mortality has been due to increase in absolute levels of factors or due to changes in impact of existing levels of health determinant. This study applies Oaxaca-Blinder decomposition to changes in childhood mortality levels in Nigeria to identify the relative contributions of the two components. Data on 31482 and 6029 under-five children in the birth history from NDHS 2013 and 2003 respectively were analyzed. The study adopted two methodologies. The first method involves the estimation of under-five mortality rate by using the life-table technique. The second method uses the Oaxaca-Blinder decomposition method to decompose changes in under-five mortality between 2003 and 2013 to determine how much of change can be attributed to impact of determinants of under-five mortality rate and how much is attributable to improved levels of the determinants. The Oaxaca-Blinder decomposition method which is a technique used to study mean outcome differences between two groups and to compare the effects of different contributing characteristics was applied. The under-five mortality rate decline from 191.2 per thousand live births to 118 per thousand live births in Nigeria. Across the region, the South South (51.4%) recorded the highest decline in under-five mortality between 2003 and 2013 and the South East (23.2%) experienced the least. There had been slight changes in the level of key determinants of under-five mortality between 2003 and 2013. Only the use of insecticides treated bed net shows a drastic improvement (14.4% in 2003 and 67.3% in 2013). Overall effect of change in factor level over time indicate that the demographic variable that contributes most to under-five mortality is birth interval less than 24months (-0.00019), followed by behavioural and health related factor- skilled delivery (-0.000032). Environmental factor-improved toilet facility (-0.00094) and the socio-economic factor is mothers with primary education (-0.000037). The slight change experienced in under-five mortality rate in Nigeria had been due to improvement in birth interval and maternal age at birth.