Breastfeeding, Mixed, or Formula Feeding at 9 Months of Age and the Prevalence of Iron Deficiency and Iron Deficiency Anemia in Two Cohorts of Infants in China.
To assess associations between breastfeeding and iron status at 9 months of age in 2 samples of Chinese infants.



Associations between feeding at 9 months of age (breastfed as sole milk source, mixed fed, or formula fed) and iron deficiency anemia (IDA), iron deficiency, and iron sufficiency were determined in infants from Zhejiang (n = 142) and Hebei (n= 813) provinces. Iron deficiency was defined as body iron < 0 mg/kg, and IDA as iron deficiency + hemoglobin < 110 g/L. Multiple logistic regression assessed associations between feeding pattern and iron status.



Breastfeeding was associated with iron status (P < .001). In Zhejiang, 27.5% of breastfed infants had IDA compared with 0% of formula-fed infants. The odds of iron deficiency/IDA were increased in breastfed and mixed-fed infants compared with formula-fed infants: breastfed vs formula-fed OR, 28.8 (95% CI, 3.7-226.4) and mixed-fed vs formula-fed OR, 11.0 (95% CI, 1.2-103.2). In Hebei, 44.0% of breastfed infants had IDA compared with 2.8% of formula-fed infants. With covariable adjustment, odds of IDA were increased in breastfed and mixed-fed groups: breastfed vs formula-fed OR, 78.8 (95% CI, 27.2-228.1) and mixed-fed vs formula-fed OR, 21.0 (95% CI, 7.3-60.9).



In both cohorts, the odds of iron deficiency/IDA at 9 months of age were increased in breastfed and mixed-fed infants, and iron deficiency/IDA was common. Although the benefits of breastfeeding are indisputable, these findings add to the evidence that breastfeeding in later infancy identifies infants at risk for iron deficiency/IDA in many settings. Protocols for detecting and preventing iron deficiency/IDA in breastfed infants are needed.



ClinicalTrials.gov: NCT00642863 and NCT00613717.
Center for Human Growth and Development, University of Michigan, Ann Arbor, MI.
Katy M
KM
Clark
Department of Pediatrics, Peking University First Hospital, Beijing, China.
Ming
M
Li
Department of Child Health Care, Zhejiang University Children's Hospital, Hangzhou, China.
Bingquan
B
Zhu
Department of Pediatrics, Peking University First Hospital, Beijing, China.
Furong
F
Liang
Department of Child Health Care, Zhejiang University Children's Hospital, Hangzhou, China.
Jie
J
Shao
Department of Pediatrics, Peking University First Hospital, Beijing, China.
Yueyang
Y
Zhang
Department of Child Health Care, Zhejiang University Children's Hospital, Hangzhou, China.
Chai
C
Ji
Department of Child Health Care, Zhejiang University Children's Hospital, Hangzhou, China.
Zhengyan
Z
Zhao
Center for Human Growth and Development, University of Michigan, Ann Arbor, MI.
Niko
N
Kaciroti
Center for Human Growth and Development, University of Michigan, Ann Arbor, MI; Department of Pediatrics and Communicable Diseases, CS Mott Children's Hospital, University of Michigan, Ann Arbor, MI.
Betsy
B
Lozoff
D018798:Anemia, Iron-Deficiency / Q000453:epidemiology* / Q000517:prevention & control; D001942:Breast Feeding / Q000009:adverse effects / Q000379:methods*; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D016001:Confidence Intervals; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D007223:Infant; D041943:Infant Formula; D007501:Iron / Q000097:blood*; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D015995:Prevalence; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment
D007501:Iron
breastfeeding; feeding; human; iron deficiency