Babies with iron deficiencies may have learning problems when they get older, according to a report released Monday. The study showed that teenagers who had low iron levels at about 17 months scored lower on cognitive tests than their peers who had adequate iron levels at the same age.

The study, led by Dr. Betsy Lozoff of the University of Michigan Ann Arbor, spanned about 20 years. Lozoff and her team studied 185 children at about one year of age. The children who screened for iron deficiencies were given supplements, but some of them were never able to achieve normal iron levels.

The children were regularly given cognitive tests to measure their ability to think, learn and remember. The participants with low iron levels at the start of the study consistently scored lower than those who had shown adequate iron levels.

The researchers found the the disparity in test scores remained throughout the course of the study, with children from poorer families testing worse as time went on.

The researchers wrote that "those in lower-socioeconomic status families seemed doubly burdened; the gap widened substantially from 10 points in infancy to 25 points at the age of 19 years."

"If direct and indirect effects of iron deficiency on the brain disrupted or delayed basic developmental processes, there could be a snowball effect," Lozoff told Reuters.

The study is published in the Archives of Pediatrics and Adolescent Medicine.