Geospatial Modelling of Stunting and Underweight Among Children Under Five Years: Insights from Sub-Saharan Africa

Abstract Child malnutrition remains a major public health challenge in Sub-Saharan Africa, with persistent disparities in stunting and underweight among children under five. This study examined subnational spatial variation and structural determinants of child growth failure across the region using Demographic and Health Survey data from 24 Sub-Saharan African countries collected between 2015 and 2023 ( n  = 198,443). Generalized additive models with spatial smoothing were used to assess geospatial patterns of stunting and underweight. Stunting prevalence ranged from 16% to 55%, and underweight from 5% to 29%, with substantial within-country heterogeneity. Children in the highest cumulative disadvantage quartile, characterized by poor maternal education, low household wealth, limited healthcare access, and reduced access to information, had substantially higher odds of stunting and underweight compared with those in the lowest quartile. Population-attributable risk estimates suggested that 45% to 89% of the burden was statistically associated with the included structural and socioeconomic risk factors under model assumptions. Spatial interpolation and smoothed intensity maps revealed localized hotspots of malnutrition that were often obscured by national averages. Despite variation in overall prevalence across countries, similar structural and socioeconomic factors were consistently associated with poor growth outcomes. These findings highlight the value of integrating high-resolution geospatial analysis with population-level impact measures to inform targeted, equity-focused nutrition policies and resource allocation strategies across Sub-Saharan Africa. Graphical Abstract Country-specific Observed vs. Theoretical Prevalence of Stunting and Underweight Among Children Under Five Across 24 African Countries (R-Script given in Appendix 2, Part C) ( a ) Stunting Prevalence ( b ) Underweight Prevalence. Observed Prevalence and Model-Based Estimates of Associated Burden. As presented in Fig. 1, only 4 out of 24 countries (17%) had stunting prevalence below the WHO-defined “low” threshold of 20%. The remaining 20 countries (83%) fell into the “medium” (20–29%) to “very high” (≥ 40%) categories, with nearly half (46%) classified as having “high” (30–39%) or “very high” (≥ 40%) stunting levels. When population-attributable risk percentages were applied, the model-based estimates suggested that the proportion of stunting burden statistically associated with the included structural and socioeconomic risk factors was substantial across countries. Under these theoretical assumptions, estimated stunting prevalence would fall below 20% in all 24 countries. Similarly, only 7 countries (29%) had underweight prevalence below the 10% threshold classified as “low,” while the majority (71%) were categorized as having “medium” (10–19%) to “high” (20–29%) prevalence, with 6 countries (25%) falling into the “high” category. Under the same model-based assumptions, the estimated proportion of underweight burden statistically associated with the included risk factors was also substantial, with theoretical underweight prevalence falling below 10% in all countries. These findings should be interpreted as theoretical, model-based estimates of associated burden rather than evidence of directly preventable reductions