ASH 2022: Risk for Iron Deficiency Higher Among Preterm Infants Who Are Formula-Fed Versus Breastfed
Lower gestational age, lower birth weight, and need for blood transfusions associated with iron deficiency in very preterm, formula-fed infants
FRIDAY, Dec. 16, 2022 (HealthDay News) –For very preterm infants – born before 31 weeks – iron deficiency is significantly more prevalent in those who are formula-fed compared with breastfed preterm infants, according to research findings presented at the annual meeting of the American Society of Hematology, held from Dec. 10 to 13 in New Orleans.
“In the past, guidelines have often assumed that because formula-fed infants are receiving enough iron from formula, they don’t need supplementation, but based on the results of this study, this may not be the case,” Grace Power, from Dalhousie University in Halifax, Nova Scotia, Canada, told Elsevier’s PracticeUpdate.
Power and colleagues analyzed health records at four- to six-month follow-up from 392 very preterm infants born in Nova Scotia from 2005 to 2018. The infants’ gestational age ranged from 23 to 30 weeks, and 285 were exclusively fed an iron-rich formula, while 107 were exclusively or partially breastfed.
The researchers found that mean iron intake from formula in the formula-fed group was 1.66 mg/kg/day, and only 20.4 percent of formula-fed infants reached an elemental iron intake ≥2 mg/kg/day. Additionally, formula-fed versus breastfed infants were less likely to receive additional iron supplements. However, the overall mean total daily iron intake from formula and supplements was higher in the formula-fed than the breast-fed group. Despite this, 36.8 percent of infants in the formula-fed group developed iron deficiency compared with 20.6 percent in the breastfed group (P = 0.002).
As a secondary objective, the researchers evaluated risk factors associated with iron deficiency among the formula-fed infants. Among iron-deficient infants who were formula-fed, mean gestational age and birth weight were both lower than in non-iron-deficient infants. The iron-deficient group also had a higher percentage of infants born with weight <1,100 g (P = 0.01). Lastly, more infants in the iron-deficient group received at least one blood transfusion (odds, 1.1 to 3.0). Other variables were comparable between the two groups. Surprisingly, iron-deficient infants had a higher daily formula intake, daily iron intake from formula, and total daily iron intake combined from formula and supplements.
“Iron deficiency is significantly more prevalent in formula-fed infants than breastfed infants despite higher iron intake overall. A possible explanation for this finding could be that the bioavailability of iron from formula is lower than from breast milk,” the authors write. “Breast milk contains lactoferrin, which aids iron absorption.” Therefore, infants may better absorb iron from breast milk than from formula.
“If clinicians can take this into consideration when providing care for these babies, then hopefully they will be able to identify more infants who are at risk for iron deficiency and provide preventative supplementation earlier,” Power said.
Future studies on the topic could help confirm the findings and inform future guidelines, the researchers concluded.
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