1. ¹Simmons College, Boston, MA, USA
2. ²Institute of Child Health, Athens, Greece
3. ³University of CA, Davis, CA, USA
4. ⁴Paidon Hospital, Athens, Greece

Correspondence: E Metallinos-Katsaras, Nutrition Dept., Simmons College, 300 The Fenway, Boston, USA 02132. E-mail: metallin@simmons.edu

Guarantor: E Metallinos-Katsaras.

Contributors: EMK participated in all phases of the study including conception, design, clinical trail implementation, data collection, data analyses and interpretation, and manuscript preparation. EVA was the principal collaborator in Greece and was involved in site selection, subject recruitment, data collection, and manuscript revisions. EP was involved in the study conception, design, development of analytic strategies, interpretation of analyses, and manuscript revisions. KGD and BL participated in study design, interpretation of analyses, and manuscript revisions. AS conducted the hematologic analyses.

Received 26 June 2002; Revised 1 March 2004; Accepted 14 April 2004; Published online 30 June 2004.

Abstract

Objective: To examine effects of iron supplementation on vigilance, attention and conceptual learning in preschool children in Greece.

Design: Randomized Double-Blind Placebo Controlled trial of iron. Randomization stratified by iron status and day care center (DCC).

Setting: Nine public DCCs in Athens, Greece.

Subjects: In all, 49 3–4-y olds (21 anemic, 28 good iron status) with birth weight not less than 2500 g, currently healthy; benign past medical history, IQ 1 s.d. below the age-adjusted mean, serum Pb 200 ppb (none exceeded 50 ppb), and height, weight and head circumference for age 10th percentile. Anemia defined as: (1) pretreatment Hgb <112 g/l and TS <16% and ferritin <12 g/L OR (2) Hgb rise of >10 g/l (T2–T0) with iron supplementation. Good iron status was defined as baseline levels of Hgb >120 g/l and either TS >20% or serum ferritin >12 g/l.

Intervention: The intervention consisted of a 2–month supplementation of 15 mg iron (and MV) vs placebo (MV alone).

Results: After iron treatment, the anemic subjects made significantly fewer errors of commission (14% higher specificity, P<0.05), exhibited 8% higher accuracy (P<0.05) and were significantly more efficient (mean difference=1.09, P<0.05) than those given placebo. These effects of iron were not found among preschoolers with good iron status. No effects of iron treatment were found on the Oddity Learning task.

Conclusions: This study demonstrated that iron supplementation of iron-deficient anemic preschoolers results in an improvement in discrimination, specifically selective attention.

Sponsorship: University of California, Davis and Nutricia Corporation.