Serum Ferritin, Dietary Iron Bioavailability, and Cognitive Function in Primary School Children in Ogun State

Iron deficiency without anaemia, detectable by serum ferritin measurement, has been associated with impaired cognitive development in school-age children, yet its dietary determinants and cognitive correlates in Nigerian school settings remain inadequately studied. This study examines serum ferritin levels, dietary iron bioavailability, and cognitive function scores in primary school children aged 6 to 11 years in Ijebu Ode and Odeda local government areas of Ogun State, South West Nigeria. An analytical cross-sectional design enrolled 300 children through school-based stratified random sampling. Serum ferritin and serum transferrin receptor were measured from venous blood samples, and iron status was classified using WHO-recommended thresholds. Dietary iron intake and bioavailability were assessed using a quantitative 24-hour dietary recall on two days, with bioavailability calculated based on meal composition using established algorithms accounting for enhancers and inhibitors. Cognitive function was assessed using the Kaufman Assessment Battery for Children, with subscores for sequential and simultaneous processing, as well as teacher-assessed academic performance scores in mathematics and literacy. Malarial parasite density and C-reactive protein were measured as potential confounders of ferritin interpretation. Multiple regression and path analysis were used to model relationships between iron bioavailability, ferritin, and cognitive scores. Findings will contribute to the understanding of subclinical iron deficiency as a cognitive risk factor in West African school-age children. Keywords: serum ferritin, iron bioavailability, cognitive function, school children, Ogun State.