Objectives: Low-birth-weight (LBW) infants (<2500 g) have an increased risk of iron deficiency (ID) during their first 6 months of life. The optimal dose and duration of iron supplementation to LBW infants are, however, unknown. The objective of the present study was to investigate the long-term effect on iron status and growth in marginally LBW (2000-2500 g) infants, of iron supplements given until 6 months of life.
Methods: In a randomized controlled trial, 285 healthy marginally LBW infants received 0, 1, or 2 mg · kg(-1) · day(-1) of iron supplements from 6 weeks to 6 months of age. At 12 months and 3.5 years of life we measured length, weight, head circumference, and indicators of iron status (hemoglobin, ferritin, mean corpuscular volume, and transferrin saturation) and assessed the prevalence of iron depletion, functional ID, and ID anemia.
Results: At 12 months of age, there was a significant difference in ferritin between the groups (P = 0.006). Furthermore, there was a significant difference in the prevalence of iron depletion (23.7%, 10.6%, and 6.8%, respectively, in the placebo, 1-mg, and 2-mg groups, P = 0.009) and similar nonsignificant trends for functional ID and ID anemia. At 3.5 years of life there were no significant differences in iron status and the mean prevalence of iron depletion was 3.2%. Anthropometric data were not affected by the intervention.
Conclusions: Iron supplements with 2 mg · kg(-1) · day(-1) until 6 months of life effectively reduces the risk of ID during the first 12 months of life and is an effective intervention for preventing early ID in marginally LBW infants.
Trial registration: ClinicalTrials.gov NCT00558454.