Temporal socio-economic inequalities in the double burden of malnutrition (DBM) among under-five Children: An analysis of within- and between-group disparities in 20 sub-Saharan African countries (2004–2024)

The double burden of malnutrition (DBM) in sub-Saharan Africa is a pressing public health issue, particularly among children under five years old. DBM encompasses both undernutrition (stunting) and overnutrition (overweight) within the same population, often shaped by socio-economic disparities. Addressing DBM in early childhood is vital, as malnutrition can lead to long-term health, cognitive, and developmental challenges. Using nationally representative data from the Demographic and Health Surveys (DHS) across 20 sub-Saharan African countries, this study examines temporal socio-economic inequalities in DBM. Countries include Zimbabwe, Kenya, Nigeria, and Mozambique, among others. DBM was defined using anthropometric measures, while socio-economic status (SES) was categorized as poor, middle, or rich. Temporal trends were analyzed, and inequalities were quantified using Erreygers Normalized Concentration Indices (ENCI) and Theil indices to explore within- and between-group disparities by SES and urban/rural residence. DBM prevalence across countries ranged from 0.2 % to 4.6 %. Declines were noted in Zimbabwe and Kenya. Socio-economic inequalities were significant, with overnutrition increasingly concentrated in wealthier households, while undernutrition remained prevalent among poorer populations. Theil index analyses revealed within-group disparities as the primary drivers of overall inequality, particularly in urban wealthier populations, though rural and low-SES groups also contributed significantly in countries like Senegal and Mali. DBM is still present in sub-Saharan Africa and is driven by socio-economic inequalities. Targeted interventions focusing on improving access to nutritious food, healthcare, and education for vulnerable populations, particularly in rural and low-SES groups, are essential to reduce malnutrition disparities. • Socio-economic Inequality Trends: Overnutrition rises in wealthier households (Kenya, Nigeria), while undernutrition lingers in poorer rural areas. • Shifting DBM Patterns: DBM increased in urban Kenya, Mozambique, Ghana but declined in Zimbabwe, Malawi. • Inequality Decomposition: ENCI & Theil indices show within-group (rural/low-SES) disparities drive DBM inequalities more than between-group. • Rural-Urban Divide: Rural areas (Senegal, Mali) face higher malnutrition; urban inequality grows in Kenya, Nigeria. • SES Gradients: Wealthier households see more overnutrition, poorer ones face undernutrition (e.g., Burundi).