Background: Iron-deficiency anemia has been associated with lowered scores on tests of mental and motor development in infancy. However, the long-term developmental outcome of infants with iron deficiency is unknown, because developmental tests in infancy do not predict later intellectual functioning.
Methods: This study is a follow-up evaluation of a group of Costa Rican children whose iron status and treatment were documented in infancy. Eighty-five percent (163) of the 191 children in the original group underwent comprehensive clinical, nutritional, and psychoeducational assessments at five years of age. The developmental test battery consisted of the Wechsler Preschool and Primary Scale of Intelligence, the Spanish version of the Woodcock-Johnson Psycho-Educational Battery, the Beery Developmental Test of Visual-Motor Integration, the Goodenough-Harris Draw-a-Man Test, and the Bruininks-Oseretsky Test of Motor Proficiency.
Results: All the children had excellent hematologic status and growth at five years of age. However, children who had moderately severe iron-deficiency anemia as infants, with hemoglobin levels less than or equal to 100 g per liter, had lower scores on tests of mental and motor functioning at school entry than the rest of the children. Although these children also came from less socioeconomically advantaged homes, their test scores remained significantly lower than those of the other children after we controlled for a comprehensive set of background factors. For example, the mean (+/- SD) adjusted Woodcock-Johnson preschool cluster score for the children who had moderate anemia in infancy (n = 30) was 448.6 +/- 9.7, as compared with 452.9 +/- 9.2 for the rest of the children (n = 133) (P less than 0.01); the adjusted visual-motor integration score was 5.9 +/- 2.1, as compared with 6.7 +/- 2.3 (P less than 0.05).
Conclusions: Children who have iron-deficiency anemia in infancy are at risk for long-lasting developmental disadvantage as compared with their peers with better iron status.