Effectiveness of weekly and daily iron administration for the prevention of iron deficiency anemia in infants.

Introduction. Iron deficiency (ID) is the most prevalent nutritional deficiency and the main cause of anemia in infants. There is consensus on daily iron supplementation as a preventive strategy; and weekly iron supplementation has also been shown to be effective, but evidence in infants is scarce. The objective of this study was to compare the effectiveness of daily versus weekly iron administration for the prevention of ID anemia (IDA) in infants. Population and methods. Randomized, controlled clinical trial. Infants seen at a public health center, without anemia at 3 months of age, were randomized into 3 groups: daily supplementation (1 mg/kg/day), weekly supplementation (4 mg/kg/week), or no supplementation (control group with exclusive breastfeeding [EB]). Anemia and ID were assessed at 3 and 6 months old. Adherence and adverse events were recorded. Data were analyzed using the R software, version 4.0.3. Results. A total of 227 infants participated. At 6 months, the group of infants with EB without supplementation (control) had a higher prevalence of ID and IDA than the intervention groups (daily and weekly). ID: 40.5% versus 13.5% and 16.7% (p = 0.002); IDA: 33.3% versus 7.8% and 10% (p < 0.001). There were no differences between the daily and weekly supplementation groups. There were also no differences in the percentage of high adherence to supplementation (50.6% daily versus 57.1% weekly) or adverse events. Conclusions. No significant differences in effectiveness were observed between daily and weekly administration for the prevention of infant IDA.