Association between total duration of breastfeeding and iron deficiency.

Maguire JL, Salehi L, Birken CS, Carsley S, Mamdani M, Thorpe KE, Lebovic G,
Khovratovich M, Parkin PC; TARGet Kids! collaboration.
MSc, FRCPC, Department of Pediatrics, St Michael's Hospital, 30 Bond St,
15CC-014, Toronto ON M5B 1W8 Canada. jonathon.maguire@utoronto.ca.

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.

[PubMed - in process]