Variations in the association between standalone and coexisting forms of undernutrition and common infectious morbidities among children in sub-Saharan Africa

Background Undernutrition is a major driver of common infectious morbidity among children under five; however, the relationship between different forms of undernutrition and childhood infectious morbidity remains poorly understood. This study examined variations in the association between different forms of undernutrition measured according to the Composite Index of Anthropometric Failure (CIAF) and common infectious morbidity among children under the age of five in sub-Saharan Africa (SSA). Methods We performed a multilevel binary logistic regression analysis using country and community clusters as random effects. Our study utilised demographic and health survey (DHS) data collected between 2016 and 2024 in 27 SSA countries. A total weighted sample of 157, 800 under-five children whose nutritional status was assessed based on the World Health Organization (WHO) anthropometric techniques and data on Acute Respiratory tract Infection (ARI) and diarrhea recorded were included. An adjusted odds ratio (AOR) with a 95% Confidence Interval (CI) was reported, and variables’ effects with a p -value less than 0.05 were declared significant determinants of common infectious morbidity. Results The prevalence of common infectious morbidity among children under five in SSA was 30.20% (95% CI: 27.34, 33.06). The lowest and highest prevalences were reported in Mozambique (16.96%; 95% CI: 16.94, 16.98) and Uganda (53.26%; 95% CI: 53.24, 53.28), respectively. The odds of infectious morbidity significantly differs between children with standalone, double and triple forms of undernutrition. Children with double (AOR: 1.25; 95% CI: 1.16, 1.34 for stunting-underweight; AOR: 1.36; 95% CI: 1.22, 1.51 for wasting-underweight) and triple undernutrition (AOR: 1.51; 95% CI: 1.36, 1.68) were more susceptible to common infectious morbidity. Conclusions Children with coexisting undernutrition were more likely to experience common infectious morbidity, and those affected by the coexistence of stunting-wasting-underweight experienced the highest odds of infectious morbidity. Among the standalone forms, only underweight children were more likely to experience common infectious morbidity. Therefore, to mitigate the burden of childhood infectious morbidity, it is crucial for policymakers to implement targeted nutritional interventions for children experiencing coexisting undernutrition.