Limited evidence suggested that iron supplementation produced a small improvement in cognitive development but had no effect on physical growth .
CONCLUSIONS : In 2 to 5 year olds , daily iron supplementation increases hemoglobin and ferritin .
There is a concerning lack of data on the effect of iron supplementation on clinical ly important outcomes including anemia , ID anemia , ID , and cognitive development .
BACKGROUND AND OBJECTIVES : Iron deficiency ( ID ) is the most common cause of anemia worldwide .
The prevalence is highest among preschool-aged children .
Iron is widely administered to children with or at risk for ID , but evidence of benefit among 2- to 5-year-old children has not been evaluated by systematic review .
We summarize the evidence for the benefit and safety of daily iron supplementation with regard to hematologic , growth , and cognitive parameters in 2 to 5 year olds .
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 r and omized 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
Limited evidence suggested that iron supplementation produced a small improvement in cognitive development but had no effect on physical growth .
CONCLUSIONS : In 2 to 5 year olds , daily iron supplementation increases hemoglobin and ferritin .
There is a concerning lack of data on the effect of iron supplementation on clinical ly important outcomes including anemia , ID anemia , ID , and cognitive development .
BACKGROUND AND OBJECTIVES : Iron deficiency ( ID ) is the most common cause of anemia worldwide .
The prevalence is highest among preschool-aged children .
Iron is widely administered to children with or at risk for ID , but evidence of benefit among 2- to 5-year-old children has not been evaluated by systematic review .
We summarize the evidence for the benefit and safety of daily iron supplementation with regard to hematologic , growth , and cognitive parameters in 2 to 5 year olds .