Relationship between iron deficiency and anemia in children younger than 4 years.

OBJECTIVE To evaluate the prevalence of anemia, iron deficiency and iron deficiency anemia in a cohort of children. METHODS A cohort study nested in a randomized field trial. Children were recruited at birth at the maternity unit of the only public hospital in the city of São Leopoldo, southern Brazil. This study assessed iron status (hemoglobin and serum ferritin) when children were 12-16 months old and later at the age of 3-4 years. Anemia was defined as hemoglobin concentration < 11.0 g/dL; iron deficiency as serum ferritin < 15.0 µg/L; and iron deficiency anemia as hemoglobin concentration < 11.0 g/dL with iron deficiency. RESULTS At age 12-16 months, the overall prevalence of anemia, iron deficiency and iron deficiency anemia was 63.7, 90.3 and 58.8%, respectively. The values for age group 3-4 years were 38.1, 16.1 and 7.4%, respectively. At age 12-16 months, 95% of anemia cases were associated with iron deficiency against only 19.3% of cases at age 3-4 years. CONCLUSIONS Iron deficiency was the main cause of anemia in the second year of life, but not at age 3-4 years. Thus, we point out that anemia in preschool children may have other causes and deserves careful assessment.