Abstract
Introduction: Iron deficiency anemia in early childhood continues to be a public health concern in
Thailand. However, before modifying the current iron supplementation policy for infants from weekly
to daily supplementation, as recommended by the World Health Organization, it is crucial to conduct
a study specifically in Thai children. Findings from this research will provide valuable evidence to
guide future policy decisions regarding iron supplementation strategies for infants.
Objective: To compare the effects of daily iron supplementation with weekly iron supplementation
in infants aged 6-12 months on the prevalence of anemia, hemoglobin level and serum ferritin
levels.
Methods: A double-blinded randomized controlled trial was conducted among 287 healthy infants
aged 6-12 months to compare two forms of iron supplementation. Group 1 (Daily group) received a
daily iron supplement of 12.5 mg for 3 months (ages 6-9 months), followed by a weekly iron
supplement of 12.5 mg until 12 months of age. Group 2 (Weekly group) received a 12.5 mg iron
supplement once a week from 6 to 12 months of age. Hemoglobin, hematocrit, serum ferritin, and
serum transferrin receptor levels were measured at the start of the study (at 6 months of age) and
during follow-up assessments at 9 and 12 months of age.
Results: At the beginning of the study, there were no differences in hemoglobin, hematocrit, and
serum ferritin between infants receiving daily and weekly iron supplementation, except for serum
transferrin receptor levels. However, when followed up at 9 months of age, serum ferritin levels
were higher in the infants who received daily iron supplementation compared to those who received
weekly supplementation. No differences were observed between the two groups in terms of
hemoglobin, hematocrit, or serum transferrin receptor levels. These findings suggest a trend where
daily iron supplementation starting at 6 months and continuing for 3 months may enhance the iron
status of infants. However, after all infants switched to weekly iron supplementation from 9 to 12
months of age, no further differences were noted between the groups. Additionally, there were no
differences in the proportions of anemia or iron deficiency between the two groups at 6, 9, or 12
months of age. The observed trend that iron levels in the group receiving daily supplementation
were better than those in the weekly group at 9 months, but showed no difference at 12 months,
may be due to the fact that weekly supplementation takes longer to show effects compared to
daily supplementation. This may result in lower effects of weekly supplementation during the early
stages. Therefore, considering the potential increase in budget, adjusting the policy to provide daily
iron supplementation may not yet be necessary for Thailand.
