Objectives: To identify common factors associated with post-neonatal, infant, child and under-5 mortality in Nigeria. Design, setting and participants: A cross-sectional data of three Nigeria Demographic and Health Surveys (NDHS) for the years 2003, 2008 and 2013 were used. A multistage, stratified, cluster random sampling method was used to gather information on 63 844 singleton live-born infants of the most recent birth of a mother within a 5-year period before each survey was examined using cox regression models. Main outcome measures: Postneonatal mortality (death between 1 and 11 months), infant mortality (death between birth and 11 months), child mortality (death between 12 and 59 months) and under-5 mortality (death between birth and 59 months). Results: Multivariable analyses indicated that children born to mothers with no formal education was significantly associated with mortality across all four age ranges (adjusted HR=1.30, 95% CI 1.01 to 1.66 for postneonatal; HR=1.38, 95% CI 1.11 to 1.84 for infant; HR=2.13, 95% CI 1.56 to 2.89 for child; HR=1.19, 95% CI 1.02 to 1.41 for under-5). Other significant factors included living in rural areas (HR=1.48, 95% CI 1.16 to 1.89 for postneonatal; HR=1.23, 95% CI 1.03 to 1.47 for infant; HR=1.52, 95% CI 1.16 to 1.99 for child; HR=1.29, 95% CI 1.11 to 1.50 for under-5), and poor households (HR=2.47, 95% CI 1.76 to 3.47 for postneonatal; HR=1.40, 95% CI 1.10 to 1.78 for infant; HR=1.72, 95% CI 1.19 to 2.49 for child; HR=1.43, 95% CI 1.17 to 1.76 for under-5). Conclusions: This study found that no formal education, poor households and living in rural areas increased the risk of postneonatal, infant, child and under-5 mortality among Nigerian children. Community-based interventions for reducing under-5 deaths are needed and should target children born to mothers of low socioeconomic status. © 2015, BMJ. All rights reserved.
