RESUMO
AIMS: To correlate the iron biochemical screening with cognitive and motor development, related to social background, in 6 to 24 month infants. METHODS: a population - based study of 276 children. The iron deficiency was determine by the modified criterion of Hillman (1996), combining three different screenings tests: serum ferritin, hemoglobin and erythrocyte protoporphyrin. To analyse development we used Bayley II Scale. RESULTS AND CONCLUSIONS: the anaemia was significative different (p< 0,05) between social levels, 36% in children with low socioeconomic background, 8% for the high one and iron deficiency without anaemia 42% in the total population. The motor development was homogeneous by social groups, showed 1% significative delay, 8% light delay. But the mental development shows significative differences (p<0,05) in both light and significative delay, been the must affected children with low socioeconomic background.