Iron Shown to Give Small Babies a Behavioral Boost

Giving babies born with a low birth weight iron supplements during the first six months of life appears to improve their behavior around preschool age, a new study found.

Compared with infants receiving placebo, those who received 1 or 2 milligrams per kilogram of ferrous succinate drops per day were significantly less likely to exceed the subclinical cutoff for behavioral problems around age 3.5, according to Dr. Staffan Berglund of Umeå University in Sweden and colleagues.

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The rates in the supplemented infants were similar to the rate among children who had been born with a normal birth weight, the researchers reported online ahead of the January issue of Pediatrics.

"These results not only suggest that the increased risk of behavioral problems in children with low birth weight may be partially prevented but also lend support to a causal relationship between preventive iron supplementation and improved neurobehavioral development in infants at risk for iron deficiency," they wrote.

"This trial supports the inclusion of marginally low birth weight infants in general iron supplementation programs during early infancy," they wrote.

Infants born weighing less than 5.5 pounds have been shown to have a greater risk of cognitive and behavioral problems compared with heavier infants. They are also at risk for iron deficiency, which has been associated with impaired neurodevelopment.

Conducted at two Swedish hospitals, the current trial examined the longer-term effects of iron supplementation in 285 infants with a marginally low birth weight of 4.4 to 5.5 pounds. The participants were given 0, 1, or 2 mg/kg/day of iron supplements, divided into two daily doses. from ages six weeks to six months.

All of the infants' parents were given standard Swedish dietary recommendations. At six weeks, 91 percent of the infants were breastfed, including 54 percent exclusively. The rates at six months were 67 percent and 5 percent.

When the children were about 3-and-a-half years old, they and 95 controls who were born with a normal birth weight underwent a psychometric test -- the Wechsler Preschool and Primary Scale of Intelligence-Third Edition -- and their parents completed a questionnaire of behavioral problems, the Achenbach Child Behavior Checklist (CBCL).

The intelligence test was the primary outcome and the behavioral assessment was the secondary outcome.

Iron supplementation did not have any effect on cognition. There were no differences in the average full-scale IQ between the placebo, 1-mg, and 2-mg supplementation groups or between the combined low birth weight infants and the healthy controls.

Supplementation did, however, reduce the percentage of children who exceeded the CBCL threshold for subclinical behavioral problems (scores exceeding the 83rd percentile).

The risk of exceeding the subclinical cutoff was significantly higher in the placebo group than in the combined supplemented group. There were significant differences between the groups on the "emotionally reactive" and "attention problems" subscales, and similar trends for four of the five other subscales, with the exception of "withdrawn."

The authors acknowledged that the study was limited by the lack of statistical power for subgroup analyses and by the possibility that the CBCL data were subject to parental bias.

Also, they noted that the trial was conducted in a high-income country with a high rate of breastfeeding.

"Additional randomized trials, exploring the effects of iron supplements in other settings and in larger populations, are needed," they wrote.