Background: Iron deficiency (ID) is the most common micronutrient deficiency worldwide, with potentially severe consequences on child neurodevelopment. Though exclusive breastfeeding (EBF) is recommended for 6 months, breast milk has low iron content. This study aimed to estimate the effect of the length of EBF on iron status at 6 - 8 months of age among a cohort of Bolivian infants. Methods: Mother-infant pairs were recruited from 2 hospitals in El Alto, Bolivia, and followed from one through 6 - 8 months of age. Singleton infants > 34 weeks gestational age, iron-sufficient at baseline, and completing blood draws at 2 and 6 - 8 months of age were eligible for inclusion (N = 270). Ferritin was corrected for the effect of inflammation. ID was defined as inflammation-corrected ferritin < 12 μg/L, and anemia was defined as altitude-corrected hemoglobin < 11 g/dL; IDA was defined as ID plus anemia. The effect of length of EBF (infant received only breast milk with no other liquids or solids, categorized as < 4, 4 - 6, and > 6 months) was assessed for ID, IDA, and anemia (logistic regression) and ferritin (Fer) and hemoglobin (Hb, linear regression). Results: Low iron status was common among infants at 6 - 8 months: 56% of infants were ID, 76% were anemic, and 46% had IDA. EBF of 4 months and above was significantly associated with ID as compared with EBF < 4 months (4 - 6 months: OR 2.0 [1.1 - 3.4]; > 6 months: 3.3 [1.0 - 12.3]), but not with IDA (4 - 6 months: OR 1.4 [0.8 - 2.4]; > 6 months: 2.2 [0.7 - 7.4]), or anemia (4 - 6 months: OR 1.4 [0.7 - 2.5]; > 6 months: 1.5 [0.7 - 7.2]). Fer and Hb concentrations were significantly lower with increasing months of EBF. Conclusions: Results suggest a relationship between prolonged EBF and ID, but are not sufficient to support changes to current breastfeeding recommendations. More research is needed in diverse populations, including exploration of early interventions to address infant IDA.
Bibliographical noteFunding Information:
This work was supported in part by NIH-NIAID K01 grant (1K01AI087724-01) grant; PHS Grant UL1 TR000454 from the Clinical and Translational Science Award Program, National Institutes of Health, National Center for Research Resource; the Emory + Children’s Pediatric Center Seed Grant Program; the National Institutes of Health / NIAID grant U19-AI057266; the Thrasher Research Fund; the International Collaborative Award for Research from the International Pediatric Research Foundation; the Laney Graduate School of Emory University; NIH T32 training grant in reproductive, pediatric and perinatal epidemiology (HD052460-01); Burroughs Wellcome Fund’s Molecules to Mankind Program (M2M); the ARCS Scholar Award from the Achievement Rewards for College Scientists (ARCS) Foundation; and the NIH T32 Vaccinology Training Program (T32AI074492). None of these funding sources played any role in the design of the study, the collection, analysis, or interpretation of data, or in the writing of the manuscript.
© 2018 The Author(s).
- Global health
- Global nutrition
- Infant nutrition
- Iron deficiency