Multidimensional Poverty-Related Variations in Infant Mortality in Nigeria

Abstract Infant Mortality Rate (IMR) and poverty level are high in Nigeria. Poverty predisposes children to avoidable deaths. The predictors of Infant Mortality (IM) are mostly examined at the national level in Nigeria, thus obscuring the effect of subgroup-specific factors. This study examined the multidimensionally poverty-related variations in infant mortality in Nigeria. This cross-sectional design study utilized 2024 Nigeria Demographic and Health Survey data. A multi-stage cluster sampling technique was used to select mothers aged 15–49 years (n = 27,534) who had ≤ 1 live birth 5 years before the survey. The Multidimensional Poverty Index (MPI) was generated from weighted responses to 7 questions: education, asset ownership, drinking water sources, toilet facility type, cooking fuel, building materials, and bank account ownership using Principal Component Analysis (PCA), but disaggregated into poor, middle, and rich. Weighted data were analyzed using a synthetic life-table method and Cox proportional hazard model (α = 5.0%). Mothers’ mean age was 29.8 ± 7.4 years, and the IMR was 74.24 (95% C.I: 65.54–82.04), 68.77 (95% C.I: 60.77–76.77), and 47.12 (95% C.I: 42.12–52.82) per 1,000 live births in the poor, middle, and rich MPI groups, respectively. The conventional U-shape of IMR by mother’s age at child’s birth and birth interval was observed across the MPI groups. The North-West and North-East mothers bear the highest burden of infant deaths in all the MPI categories. The hazard of IM was 52.9% (uHR = 1.529, 95% C.I = 1.343–1.741, p < 0.001) and 30.1% (uHR = 1.301, 95% C.I = 1.134–1.492, p < 0.001) higher among the children of mothers in the poor and middle MPI categories, respectively, compared to their rich counterparts. The predictors of IM among Poor mothers are: region, children ever born (CEB), birth order, birth interval, place of delivery, and COVID-19 vaccine receipt; Middle class are: mother’s age at the child's birth, residence, and birth interval; and Rich are: CEB, birth order, child’s sex, ethnicity, and partner’s education. IMR in Nigeria is high, but the children of poor mothers are mostly affected. Variation existed in the identified predictors of IM across MPI groups. Consequently, frameworks for IM reduction in Nigeria should target the MPI group-specific predictors, with priority attention given to poor mothers.