Iron-deficiency anemia in infancy and poorer cognitive inhibitory control at age 10 years.

Aim: The aim of this study was to assess the effects of iron-deficiency anemia (IDA) in infancy on executive functioning at age 10 years, specifically inhibitory control on the Go/No-Go task. We predicted that children who had IDA in infancy would show poorer inhibitory control.

Method: We assessed cognitive inhibitory control in 132 Chilean children (mean [SD] age 10 y [1 mo]): 69 children had IDA in infancy (45 males, 24 females) and 63 comparison children who did not have IDA (26 males, 37 females). Participants performed the Go/No-Go task with event-related potentials. Group differences in behavioral (accuracy, reaction time) and electrophysiological outcomes (N2 and P300 components) were analyzed using repeated-measures analyses of variance. N2 and P300 are interpreted to reflect attention and resource allocation respectively.

Results: Relative to comparison participants, children who had IDA in infancy showed slower reaction time (mean [SE], 528.7 ms [14.2] vs 485.0 ms [15.0], 95% confidence interval [CI] for difference between groups 0.9-86.5); lower accuracy (95.4% [0.5] vs 96.9% [0.6], 95% CI -3.0 to -0.1); longer latency to N2 peak (378.9 ms [4.9] vs 356.9 ms [5.0], 95% CI 7.5-36.6); and smaller P300 amplitude (4.5 μV [0.8] vs 7.6 μV [0.9], 95% CI-5.5 to -0.5).

Interpretation: IDA in infancy was associated with slower reaction times and poorer inhibitory control 8 to 9 years after iron therapy. These findings are consistent with the long-lasting effects of early IDA on myelination and/or prefrontal-striatal circuits where dopamine is the major neurotransmitter.