Association Between Total Duration of Breastfeeding and Iron Deficiency

OBJECTIVE: To determine whether there is an association between the total breastfeeding duration and iron stores, iron deficiency, and iron deficiency anemia in healthy urban children. METHODS: A cross-sectional study of healthy children, aged 1 to 6 years, seen for primary health care between December 2008 and July 2011 was conducted through the TARGet Kids! practice-based research network. Univariate and adjusted regression analyses were used to evaluate an association between total breastfeeding duration and serum ferritin, iron deficiency, and iron deficiency anemia. RESULTS: Included were 1647 healthy children (median age 36 months) with survey, anthropometric, and laboratory data. An association was found between increasing duration of breastfeeding and lower serum ferritin (P = .0015). Adjusted logistic regression analysis revealed the odds of iron deficiency increased by 4.8% (95% confidence interval: 2%-8%) for each additional month of breastfeeding. Exploratory analysis suggested an increasing cumulative probability of iron deficiency with longer total breastfeeding duration with an adjusted odds ratio of 1.71 (95% confidence interval: 1.05-2.79) for iron deficiency in children breastfed over versus under 12 months of age. The relationship between total breastfeeding duration and iron deficiency anemia did not meet statistical significance. CONCLUSIONS: Increased total breastfeeding duration is associated with decreased iron stores, a clinically important association warranting additional investigation.