SAN DIEGO – The administration of iron supplements to marginally low-birth-weight children during infancy may have a positive effect on cognitive development and behavioral problems by the time they reach the age of 7 years, results from a novel randomized study demonstrated.
“It is known that iron is essential for brain development and it is known that low-birth-weight infants are at risk of iron deficiency and they are also at risk of cognitive-behavioral problems,” Dr. Magnus Domellöf, one of the study authors, said in an interview in advance of the annual meeting of the Pediatric Academic Societies. “However, this is the first randomized, controlled intervention trial to show that early iron supplementation of low-birth-weight infants improves brain function at school age. Our focus has been infants with marginally low-birth-weight (2,000-2,500 g), which constitutes about 5% of newborns in the United States, so it is a large group which is seldom studied.”
For the randomized controlled trial, Dr. Domellöf, professor and head of pediatrics in the department of clinical sciences at Umea University, Sweden, and his associates enrolled 285 healthy, marginally low-birth-weight (MLBW) infants to receive 0, 1, or 2 mg/kg per day of iron supplements from 6 weeks to 6 months of age. An additional 95 normal-birth-weight controls were included at 3 years of age. When the cohort reached the age 7, a pediatric psychologist assessed 70 controls and 186 MLBW children with the Wechsler Intelligence Scale of Children (WISC-IV), while parents of 74 controls and 189 MLBW children completed the validated Child Behavior Checklist (CBCL), a widely used tool to identify problem behavior in children.
The researchers found that MLBW children showed signficantly lower WISC-IV scores, compared with controls, in verbal comprehension (104.9 vs. 107.7; P = .039), but not in perceptual reasoning (P = .402), working memory (P = .560), processing speed (P = .896), or full-scale IQ (100.4 vs. 102.9; P = .236). The differences in verbal comprehension remained after controlling for maternal age and education and were not related to iron supplementation in infancy.
Dr. Domellöf went on to report that the CBCL externalizing score was significantly higher in the placebo group, compared with the two iron groups (median scores of 49 and 44, respectively; P = .015). The proportion of children with a total CBCL score above the cut-off for clinical problems was higher in MLBW children than for controls (5.6% vs 2.7%) and the proportion of children in the placebo group was higher than in the 1-mg and 2-mg supplementation groups (10% vs. 1.8% and 4.2%), but these differences did not reach statistical significance.
“Our study suggests that it is actually possible to prevent some behavioral problems at school age in low-birth-weight infants by giving them iron supplements during infancy,” Dr. Domellöf said. “All low-birth-weight infants [less than 2,500 g] should receive iron supplements during the first 6 months of life.”
Dr. Domellöf reported having no relevant financial disclosures.
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