Prevalence and of Factors Associated With Under-Five Child Mortality in Nigeria: A Comparative Study Between Cox PH and Cox Frailty Model

Background: Under-five mortality is one of the substantial indicators for childrens’ health well-being and, consequently, it’s level of socio-economic development. The primary focus of this study was to estimate the prevalence as well as to identify the factors that were associated with under-five mortality in Nigeria. Methods: This research utilized the most recent secondary data for Nigeria called Nigeria Demographic and Health Survey NDHS (2018). The response of this study was the death of the kids within 59 months from their birth. Cox PH and Cox Frailty models were adapted to identify the factors of under-five child mortality. Findings: A total of 33,924 under-five live-born, the percentage of death before reaching age five was 9.47% among Nigerian children. The model reported that educated mother (HR=0.936; CI: 0.833-0.950) and father (HR=0.803; CI: 0.719-0.895), richer family (HR=0.668; CI: 0.586-0.762), female child (HR=0.865; CI: 0.807-0.927), larger birth interval (HR=0.771; CI: 0.683-0.870) had lower hazard of under-five death. On the other hand, multiple births (HR=3.020; CI: 2.692-3.387) and small-size babies at birth (HR=1.352; CI: 1.226-1.490) were strongly associated with the high risk of under-five mortality. Based on the magnitude of AIC & BIC, the community-level shared frailty model was the best-fitted model with 0.198. So, factors operating at the community level are responsible for approximately 20% of individuals' variations regarding under-five children's death. Interpretation: The Nigerian Federal Ministry of Health can play an essential role in providing child care and maternal health-related knowledge to new and old parents. Besides, agencies should offer community-level interventions to Nigerian communities to reduce the mortality of under-five Nigerian children. Funding Statement: No fund has been received. Declaration of Interests: Authors declare no competing interests.