Objective: To determine the long-term effects of iron deficiency in infancy.
Design: Longitudinal follow-up study of children who had been tested and treated for iron deficiency as infants.
Setting: Periurban community near San Jose, Costa Rica.
Participants: Of the original 191 participants, 87% were reevaluated at 11 to 14 years old (average age: 12.3 years). The children were free of iron deficiency and growing normally by US standards. Those who had chronic, severe iron deficiency in infancy (n = 48) were compared with those who had good iron status before and/or after iron therapy in infancy (n = 114).
Outcome measures: Comprehensive set of cognitive, socioemotional, and motor tests and measures of school functioning.
Results: Children who had severe, chronic iron deficiency in infancy scored lower on measures of mental and motor functioning. After control for background factors, differences remained statistically significant in arithmetic achievement and written expression, motor functioning, and some specific cognitive processes (spatial memory, selective recall, and tachistoscopic threshold). More of the formerly iron-deficient children had repeated a grade and/or been referred for special services or tutoring. Their parents and teachers rated their behavior as more problematic in several areas, agreeing in increased concerns about anxiety/depression, social problems, and attention problems.
Conclusions: Severe, chronic iron deficiency in infancy identifies children who continue at developmental and behavioral risk >10 years after iron treatment.