Background: Previous studies on the cognitive effects of iron treatment have focused on anemic or non-anemic iron-deficient infants. The effect of iron supplementation on cognitive development among iron-sufficient infants has not been studied. The aim of the present study was to examine the effect of iron supplementation on performance in the Bayley Scales of Infant Development (BSID) and anthropometric measurement in 6-month-old iron-sufficient healthy infants.
Methods: Healthy, iron-sufficient infants who were 6 months of age and were attending the Well Baby Clinic were considered for enrollment. Infants were randomly assigned to take ferrous sulfate supplementation (1 mg/kg per day) or no supplementation and were followed for 3 months. Anthropometric measurement, hematologic status and BSID were evaluated on admission and after 3 months.
Results: Seven infants in the intervention group and nine in the control group completed the study. No significant differences were observed in anthropometric measurements and complete blood counts between the two groups after the 3 month study period. The mean transferrin saturation (TS) level decreased significantly in the control group during the study period (from 15.3~2.6 to 7.8~5.1%; P=0.0117), but no such reduction was seen in the intervention group. At the end of the study, the TS of the control group was found to be significantly lower than that of the intervention group (7.8~5.1 vs 19.9~7.9%, respectively; P=0.0033). The BSID scores of infants in both groups were within the normal range on admission and at the end of the study period.
Conclusions: Short-term iron supplementation did not change developmental test scores despite the hematologic response in iron-sufficient healthy infants. The high prevelance of iron-deficiency anemia and its relationship with adverse developmental outcome suggests that prevention of iron-deficiency anemia with prophylaxis needs to be emphasized, rather than treatment.