Prevalence and risk factors for iron-deficiency anemia in very-low-birth-weight preterm infants at 1 year of corrected age

Abstract

Objective: To determine the prevalence of iron-deficiency anemia and iron deficiency at 1 year of corrected age (CA) in preterm very-low-birth-weight infants, and to identify risk factors for iron-deficiency anemia.

Methods: A cohort of infants with birth weight <1500 g and gestational age <34 weeks on iron prophylaxis were followed up to 12 months' CA. Anemia diagnosis was based on hemoglobin <11 g/dl. Iron deficiency was defined by ferritin levels <10 μg/l, transferrin saturation <10% and mean corpuscular volume <80 fl. Neonatal data and feeding at 6 and 12 months' CA (breastfeeding and/or cow's milk or infant formula); hospitalizations during the first year and weight, head circumference, body mass index and length at 12 months' CA were analyzed.

Results: Prevalence of anemia in 310 participants was 26.5% [95% confidence interval (CI) 21.8-31.6%] and of iron deficiency was 48% (95% CI 39.0-56.9%). Increased consumption of cow's milk at 6 months [relative risk (RR) 1.687; 95% CI 1.146-2.483], lower maternal age (RR 0.953; 95% CI 0.923-0.983), high number of pregnancies (RR 1.256; 95% CI 1.122-1.406) and being born small for gestational age (RR 1.578; 95% CI 1.068-2.331) were independently associated with anemia after adjustments.

Conclusions: Prevalence of anemia is high at 1 year of CA. Dietary and environmental education strategies may help prevent anemia after discharge.

Keywords: anemia; iron deficiency; low birth weight; premature.