Title: Iron Deficiency After Arrival is Associated with General Cognitive and Behavioral Impairment in Post-Institutionalized Children from Eastern Europe
Study Location: N/A
Type of Paper: Original Article
Purpose: To investigate the association between iron deficiency and cognitive and behavioral development in recent adoptees.
Measures: Anthropometrics: weight-for-age, height-for-age, head circumference-for-age, weight-for-height; Iron deficiency: transferrin saturation <12%, serum ferritin <12μg/L, and mean corpuscular volume <74fL; Cognitive Development: Mullen Scales of Early Learning/Mullen Early Learning Composite Score; Behavior: Behavior Rating Scale from Bayley Scales of Infant Development II (investigator rating), temperament/TBAQ-R (parent rating) Participants: 57 recent adoptees from Russia, Kazakhstan and Ukraine between the ages of 8.9 and 45.6 months at baseline.
Methods: Participants were seen at baseline (approximately 1 month after arrival to US) and follow-up 6 months later. Anthropometrics, iron deficiency and cognitive development were assessed at baseline and follow-up. Parent-rated temperament (TBAQ-R) was assessed at baseline and behavior composite scores were assessed at follow-up only.
Results: Twenty-six percent of participants at baseline were iron deficient. There was no significant change in iron deficiency from baseline to follow-up. Rapid catch-up growth rates were associated with poorer iron status at follow-up. Iron deficiency at baseline was not associated with the Mullen Scales (cognitive development) or behavior measures. Those who were iron deficient at baseline, however, did tend to be more fearful on the parent-rated TBAQ-R at baseline.
At follow-up, those with iron deficiency tended to have lower scores on the expressive language subscale and the Mullen Early Learning Composite. These children were more likely to score below average on the Mullen Early Learning Composite compared to those children who were iron sufficient. Older age at adoption and smaller head circumference were also related to a greater tendency to score below average. Iron deficiency at follow-up was also associated with greater fearfulness, activity and impulsivity on the TBAQ-R. Children with iron deficiency at follow-up also had lower inattention and hyperactivity scores (investigator-rated). Upon further analysis, inattention and hyperactivity mediate the relationship between iron deficiency and Mullen Early Learning Composite Scores.
Conclusions and Implications: There was no association between iron status and cognitive abilities at baseline. The absence of distinction between iron deficient and iron sufficient children at baseline could be due to both groups having other dominant risk factors soon after adoption, such as macronutrient malnutrition and lack of psychosocial stimulation during institutionalization. However, those who remained iron deficient or developed iron deficiency between baseline and follow-up tended to score below average on the Mullen Early Learning Composite at follow-up. Due to this finding, it is recommended that iron status be followed-up at least through the first 6 months post-adoption despite good iron status at arrival. Those with iron deficiency exhibited increased fearfulness – a finding that is consistent in studies of iron deficiency in other populations. However, the finding that iron deficient children displayed hyperactivity is inconsistent with other descriptions of infants and children with iron deficiency. A possible explanation for this discrepancy is that effects on development and behaviors vary based on duration and severity of iron deficiency. Additionally, children in the sample of the present study did not have severe iron deficiency, and few had anemia or chronic iron deficiency (unlike those children profiled in past studies). Finally, the association between iron deficiency and poor performance on the Mullen Early Learning Composite was mediated by behavioral problems during testing. However, due to behavioral problems during testing, these scores may not be the best indication of cognitive competence.
Limitations: Major limitations of the study include a small sample size and limited scope of international adoptees (only adoptees from 3 Eastern Europe and Central Asian countries were included). The study only looked at the simultaneous occurrence of iron deficiency and development and behavior. Future research should be done to investigate whether these effects persist after children are treated for iron deficiency.
Citation/Reference: Fuglestad, A.J., Georgieff, M.K., Iverson, S.L., Miller, B.S., Petryk, A., Johnson, D.E., Kroupina, M.G. Iron Deficiency After Arrival is Associated with General Cognitive and Behavioral Impairment in Post-Institutionalized Children Adopted from Eastern Europe. Maternal and Child Health Journal. 2012. ePub. http://www.ncbi.nlm.nih.gov/pubmed/22872286