Functional Significance Of Iron Deficiency In Children

Researchers led by Dr. Betsy Lozoff, director of the U-M Center for Human Growth and Development (CHGD) and professor of pediatrics, have been conducting a longitudinal study of 191 infants born in 1981-83 in a lower-middle class community in Costa Rica. The infants, who were screened and treated for iron deficiency, had been previously re-evaluated at five years of age.

Recently, 167 of them were re-evaluated at ages 10-13. "Of the 167 children," said Lozoff, "48 had been severely, chronically iron deficient as infants and 119 had been iron sufficient either before or after iron therapy in infancy. The severe, chronic iron deficient group consisted of children who had had moderate iron-deficiency anemia as infants and those with higher hemoglobin levels with iron deficiency that did not completely correct with iron therapy in infancy."

The most recent evaluation included measures of cognitive and motor functions, scholastic achievement, and behavioral problems. The results were reported last month at the American Pediatric Society Meeting in Washington, D.C.

"At the five-year follow-up, we found that children who had had severe, chronic iron deficiency as infants tested lower than the children who had had better iron status on a variety of measures---visual-motor integration, quantitative or numerical concepts, visual matching, and performance IQ.

"Unfortunately, the trends continued at ages 10-13 and had a negative effect on their scholastic achievement scores," Lozoff said. "Although all of them were in the 'normal range,' we found that the children who had severe, chronic iron deficiency now scored lower on standardized achievement tests---about 7 points lower on tests [100 point scales] of reading, writing and arithmetic, with particularly marked differences in written expression. Sub-tests of IQ measures also determined that they had acquired less general knowledge of the world and were less able to do abstract reasoning. Their motor scores also continued to be lower," Lozoff said.

The children who had severe, chronic iron deficiency also scored higher for behavioral problems, which may have interfered with their learning, Lozoff suggested. "These children had more internalizing problems---they were reported to be more anxious and socially withdrawn and to have more somatic or physical complaints than the children who had had better iron status in infancy. In fact, by U.S. standards, their internalization scores were in the clinical range---that is, they would be considered for mental health evaluation and treatment in the United States."

The researchers will follow the children over the next five years, examining the impact of severe chronic iron deficiency in infancy on classroom grades, retention, need for special education or tutoring, and school dropout rates.

Lozoff's colleagues on the recent follow up study are Eileen Mollen, psychologist and assistant professor, U-M Department of Pediatrics and Communicable Diseases; John Hagen, research scientist at CHGD and U-M professor of psychology; Abraham W. Wolf, assistant professor of psychology, Department of Psychiatry, Case Western Reserve University School of Medicine; and Elias Jimenez, director of research, Hospital Nacional de Ninos, Costa Rica.