International Journal of Statistics and Applications 2019, 9(2): 59-66 DOI: 10.5923/j.statistics.20190902.03 Survival Analysis of Under-five Mortality and Its Associated Determinants in Nigeria: Evidence from a Survey Data Anthony I. Wegbom 1,* , Isaac D. Essi 1 , Victor A. Kiri 2 1 Department of Mathematics, Rivers State University, Port Harcourt, Nigeria 2 Department of Mathematics, Physics & Electrical Engineering, Northumbria University, Newcastle upon Tyne, United Kingdom Abstract Child mortality is a deciding factor of the well-being of a population and often serves as a pointer of the socio-economic status and health development of a nation. A 2017 report on child mortality indicated most child deaths happened in two regions of the world: Sub-Saharan Africa (38%) and South Asia (39%). In Nigeria, around 839,500 children die each year prior to their fifth birthday. This places Nigeria third among the nations of the world with the highest absolute number of child deaths, next to India and Pakistan. Our study is aimed at assessing the effect of socioeconomic, bio-demographic and health-related factors on mortality risk among the under-five (U5M) of Nigerian children, using the 2013 Nigerian Demographic and Health Survey data. We used the non-parametric Kaplan-Meier survival method to assess the influence of the sets of candidate factors on the survival of children aged under-five (U5) and used the Cox proportional hazard model to assess the form of the influence on mortality risk. Those found to have a significant influence on the risk in Nigeria were: mother's educational level, wealth index, marital status, place of residence, sex of the child, region, maternal age at childbirth, number of children ever born, birth interval, and child size at birth. We also found evidence that U5M in Nigeria may be more associated with social, economic, environmental and demographic factors, than with health-related factors. We conclude that for Nigeria to achieve the Sustainable Development Goals, its public health interventions may need to take into account, the factors we have identified. Keywords Survival analysis, Under-five mortality, Determinants, Nigerian Demographic and Health Survey, Nigeria 1. Introduction Globally, it was estimated that about 5.4 million children aged under-five die each year, with huge variations and trends across regions and nations [1]. A 2017 UNICEF report on child mortality states that most of these child deaths happened in two particular regions: sub-Saharan Africa (38%) and South Asia (39%). Over half of these deaths occurred in just five nations: the Democratic Republic of the Congo, India, Ethiopia, Nigeria and Pakistan. All things considered, 1 out of every 13 children born in sub-Saharan Africa dies before their fifth birthday as against 1 out of every 185 in high-income countries- meaning that the highest proportions of under-five mortality are concentrated in sub-Saharan Africa and South Asia [1]. About 839,500 Nigeria children die each year before their fifth birthdays. * Corresponding author: wegbomanthony@gmail.com (Anthony I. Wegbom) Published online at http://journal.sapub.org/statistics Copyright © 2019 The Author(s). Published by Scientific & Academic Publishing This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ This places Nigeria third among the countries of the world with the highest absolute number of child deaths, next to India and Pakistan [2-4]. The Millennium Development Goal (MDG) progress report of 2013 revealed that at the national level, only 1/5 of the countries with a high death rate of about 40 deaths per 1000 or more had the chance to achieve MDG Goal 4- the absence of adequate progress in reducing the rates of under-five mortality by many of the developing countries, has resulted in the newly adopted Sustainable Development Goals (SDGs), with the target of reducing U5 mortality to 25 per 1,000 or less by 2030 [5]. While U5 mortality rates have dropped globally by about 56%, that is, from 93 deaths/1,000 live births in 1990 to 41 deaths/1,000 live births in 2016, the rate of progress has been unbalanced across nations with the worst in sub-Saharan Africa where accelerated and sustainable improvements are urgently needed [1]. According to UNICEF 2017, in excess of 50 nations, including Nigeria are missing their SDG targets on child survival, and nearly 60 million children under age 5 will die between 2017 and 2030 if current trends continue. Nigeria is among the nations in sub-Saharan Africa with