Brain Derived Neurotrophic Growth Factor and Cognitive Function in Children with Iron Deficiency Anemia

Background: The negative effects of iron deficiency anemia (IDA) on cognition are well documented in previous studies; however, distinct mechanisms of these effects are still a matter of debate. Brain derived neurotrophic factor (BDNF) has an important role in brain functions specially memory and learning and was reported to be low in IDA in animal studies.
Objective: This study was thus designed to estimate BDNF serum level in patients suffering from IDA and correlate its level to their cognitive function.
Study Design: Cross sectional case-control study.
Place and Duration of the Study: The Outpatient Clinic in the Children`s Hospital, Ain Shams University, between May, 2009 and March, 2010.
Methods: The study was conducted on 27 child suffering from IDA (hemoglobin <11gm/dl and serum ferritin<12ng/ml) with a mean age of 7.96±3.06 years. Full history taking and thorough clinical examination were done. Complete blood count, serum ferritin and BDNF were measured. Cognitive assessment using Wechsler intelligence test was performed for enrolled children. Fifty healthy age and sex matched children were enrolled as controls.
Results: Wechsler intelligence test showed significantly lower verbal, performance and total IQ values among IDA patients compared to controls. Total IQ score showed significant positive correlation with hemoglobin level and significant negative correlation with red cell width (RDW). Although BDNF level was not significantly lower in IDA patients, it showed a significant positive correlation with object assembly. Multiple regression analysis using total IQ as a dependent variable showed that RDW was the most determinant factor that affected IQ scores.
Conclusion: Wechsler IQ test results were adversely affected in IDA patients. BDNF level was not significantly lower in IDA children but it showed a significant positive correlation with one of Wechsler IQ test items in such patients. Larger scale studies are recommended to further investigate BDNF as a possible mediator that disturb cognitive functions in IDA and explore other mediators.