Dose-response relationships between iron deficiency with or without anemia and infant social-emotional behavior

Objective To assess dose-response relationships between severity of iron deficiency (ID) and infant social-emotional behavior. Study design The study group was a cohort of 9- to 10-month-old African-American infants (n = 77 with final iron status classification). The infants were given oral iron for 3 months. Social-emotional outcomes included mother and examiner ratings at 9 and 12 months and quantitative behavioral coding from videotape at 12 months. General linear model analyses tested for linear effects of iron status group (ordered from worst to best: iron-deficient anemia [IDA], nonanemic iron-deficient [NA ID], iron-sufficient [IS]) and determined thresholds for effects. Results There were significant (P < .05) linear effects of poorer iron status for shyness (increasing, maternal rating), orientation-engagement, and soothability (decreasing, examiner ratings), and the following quantitatively coded behaviors: positive affect (decreasing) and latencies to engage with the examiner (increasing) and move away from the examiner (decreasing). The threshold for all but 1 effect was ID with or without anemia versus IS. Conclusions Infant social-emotional behavior appears to be adversely affected by ID with or without anemia. ID without anemia is not detected by common screening procedures and is more widespread than IDA. Infant social-emotional behavior can profoundly influence the care-giving environment, with repercussions for overall development.