Plasma hepcidin concentrations and factors associated with hemoglobin levels in infants and young children in Zimbabwe
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Date
2014-03-07
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Johns Hopkins University
Abstract
Iron metabolism is very dynamic over the first year of life. Anemia is common in sub-Saharan African infants, particularly in the context of HIV infection. Hepcidin, a peptide hormone whose synthesis is simultaneously regulated by iron status and the innate immune system, has evolved as the master regulator of iron metabolism, thereby linking iron homeostasis, inflammation, infection and anemia. However little is known about normal hepcidin values in infancy, its role in the pathogenesis of anemia during infancy or its role in the pathology of HIV infection or exposure. Plasma hepcidin concentrations were higher in 3-month-old (median 9.7 ng/mL [IQR 2.5, 19.3]), than in 6-month-old (4.5 ng/mL [IQR 0.5, 7.3]) and 12-month-old infants (1.9 ng/mL [IQR 0.7, 6.2)]) (p<0.001, Kruskal–Wallis) among healthy, non-anemic Zimbabwean infants with normal iron parameters at 3 (n=60), 6 (n=47) and 12 (n=40) months of age. The correspondingly lower levels of plasma hepcidin at 6 and 12 months in healthy non-anemic infants is likely a physiologic response to mobilize iron stores and increase iron absorption to prevent anemia. Plasma hepcidin concentrations were higher in HIV-infected compared to HIV exposed uninfected (HEU) and HIV-unexposed groups throughout infancy and correlated with levels of plasma ferritin and C- reactive protein (CRP). HEU infants also had higher levels of plasma hepcidin and inflammation (alpha-1-acid glycoprotein (AGP) and CRP) compared to HIV unexposed infants. Overall, anemia had no effect on plasma hepcidin concentrations during infancy except in HIV unexposed infants. Plasma hepcidin declined with age in all groups; girls had higher plasma hepcidin concentrations than boys. Plasma hepcidin concentrations appear to be driven by inflammation in infants, as has been shown in adults. We did not find a significant association between infant and young child feeding (IYCF) indicators and hemoglobin levels in children 6-24 months using data from the 2010-11 Zimbabwe Demographic and Health Survey. However, Water, Sanitation and Hygiene (WASH) practice indicators were associated with hemoglobin levels in young Zimbabwean children adjusting for biological and social factors and warrant further investigation in randomized controlled trials.
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Keywords
hepcidin, anemia, infancy, HIV