Prolonged Exclusive Breastfeeding Duration Is Positively Associated with Risk of Anemia in Infants Aged 12 Months

Background: The association between exclusive breastfeeding duration and infant anemia is not clear.

Objective: This study aimed to assess the association of exclusive breastfeeding duration with risk of anemia in infants at 12 mo of age and in children aged 48-71 mo in mainland China.

Methods: Detailed breastfeeding information and anthropometric data were obtained for 65,256 children enrolled in the Jiaxing Birth Cohort at 1, 3, and 6 mo of age. Hemoglobin was measured in 25,549 children at 12 mo and in 32,770 children between the ages of 48 and 71 mo. Anemia was defined as hemoglobin concentrations <110 g/L in children aged <60 mo and <115 g/L in children aged ≥60 mo. The associations between exclusive breastfeeding duration and risk of anemia were assessed as adjusted ORs by using multiple logistic regression.

Results: Overall anemia prevalences at 12 and 48-71 mo were 24.9% and 9.9%, respectively. Exclusive breastfeeding for ≥6 mo, but not for 3-5 mo, was significantly associated with a higher risk of anemia in infants at age 12 mo (OR: 1.15; 95% CI: 1.02, 1.29; P = 0.02) compared with exclusive breastfeeding for <3 mo. For young children aged 48-71 mo, this finding was only marginally significant (OR: 1.13; 95% CI: 0.99, 1.29; P = 0.08). Prolonged duration of exclusive breastfeeding was also significantly associated with decreased hemoglobin concentrations of -0.56 g/L (95% CI: -1.10, -0.03; P = 0.04) in infants and -0.99 g/L (95% CI: -1.44, -0.55; P < 0.001) in young children.

Conclusions: Exclusive breastfeeding for ≥6 mo was associated with an increased risk of anemia in infants aged 12 mo and with lower hemoglobin concentrations in both infants aged 12 mo and young children aged 48-71 mo. Parents should provide infants with an adequate source of iron after 6 mo of exclusive breastfeeding.