Daily multivitamins with iron to prevent anemia in high-risk infants: a randomized clinical trial

The goal of this study was to assess the effectiveness of multivitamins with iron as prophylaxis against iron deficiency and anemia in infancy.

The study was a double-blinded, randomized, pragmatic, clinical trial conducted at 3 urban primary care clinics. Subjects included healthy, full-term infants who were enrolled at their 6-month well-child visit. Infants were randomly assigned to receive standard-dose multivitamins with or without iron (10 mg/day). Parents administered multivitamins by mouth daily for 3 months. Laboratory results at 9 months of age were analyzed for the presence of anemia and/or iron deficiency. Anemia was defined as hemoglobin level <11.0 g/dL. Iron deficiency was initially defined as any abnormal laboratory value of the following: mean corpuscular volume combined with red cell distribution width or zinc protoporphyrin (with blood lead level <10 microg/dL) for most subjects and ferritin, transferrin saturation, or reticulocyte hemoglobin content for a subset. Subsequent analyses defined iron deficiency as any 2 abnormalities of the above laboratory outcomes, except hemoglobin.

The control (n = 138) and intervention (n = 146) groups were equivalent with respect to all important sociodemographic and nutritional variables. At 9 months of age, anemia was found in 21% of infants (n = 58). A total of 229 (81%) had iron deficiency on the basis of 1 abnormal laboratory indicator and 139 (49%) on the basis of 2 abnormal laboratory indicators. No difference existed in the occurrence of anemia and iron deficiency between the intervention and control groups. In the intervention group, 22% and 78% of 138, respectively, were anemic or had 1 abnormal laboratory outcome indicative of iron deficiency. In the control group, 19% and 84% of 144 were anemic or iron deficient. When stratified by adherence, no differences in hematologic outcomes between groups were noted. However, in multivariate logistic regression, infants whose mothers were anemic during pregnancy were 2.15 times more likely than others to have any laboratory abnormality (95% confidence interval: 1.14-4.07). Increasing adherence, regardless of group assignment, was associated with a 0.56 times reduced risk of any abnormality (95% confidence interval: 0.41-0.76).

On the basis of intention-to-treat analysis, multivitamins with iron was not effective in preventing iron deficiency or anemia in 9-month-old infants. However, effective prevention and treatment of maternal anemia during pregnancy and giving multivitamins with or without additional iron during infancy may prove to be important approaches to the prevention of iron deficiency among high-risk children. Because of the consequences of iron deficiency and its high prevalence among low-income infants, additional investigation in these areas is warranted.