Iron deficiency anemia and iron therapy effects on infant developmental test performance

The behavioral effects of iron deficiency and its treatment were evaluated in a double-blind randomized controlled community-based study of 191 Costa Rican infants, 12 to 23 months of age, with various degrees of iron deficiency. The Bayley Scales of Infant Development were administered before and both 1 week and 3 months after IM or oral administration of iron. Appropriate placebo-treated control infants were also tested. Infants with iron deficiency anemia showed significantly lower mental and motor test scores, even after considering factors relating to birth, nutrition, family background, parental IQ, and the home environment. After 1 week, neither IM nor oral iron treatments differed from placebo treatment in effects on scores. After 3 months, lower mental and motor test scores were no longer observed among iron-deficient anemic infants whose anemia and iron deficiency were both corrected (36%). However, significantly lower mental and motor test scores persisted among the majority of initially anemic infants (64%) who had more severe or chronic iron deficiency. Although no longer anemic, they still showed biochemical evidence of iron deficiency after 3 months of treatment. These persistent lower scores suggest either that iron therapy adequate for correcting anemia is insufficient to reverse behavioral and developmental disturbances in many infants or that certain ill effects are long-lasting, depending on the timing, severity, or chronicity of iron deficiency anemia in infancy.