The Zinc Protoporphyrin/Heme Ratio in Premature Infants: Has it Found its Place?

Kling, Pamela J.

doi:10.1016/j.jpeds.2005.09.029

Cited by 10 publications

(8 citation statements)

References 17 publications

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“…Anaemia in pregnant women was defined as Hb less than 11 g/dl (WHO, 2001). Iron deficiency was defined as ZPP above 80 mmol/mol haem for adults and infants (Hinchliffe, 1999;Rettmer et al, 1999;Domellof et al, 2002;Juul et al, 2003;Soldin et al, 2003;Kling, 2006;Lott et al, 2006). No published ZPP cutoff values are established to diagnose iron deficiency in cord blood.…”

Section: Definitionsmentioning

confidence: 99%

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A cohort study of haemoglobin and zinc protoporphyrin levels in term Zambian infants: effects of iron stores at birth, complementary food and placental malaria

et al. 2007

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Objective: To examine zinc-protoporphyrin (ZPP) and haemoglobin levels, and to determine predictors of iron deficiency anaemia (IDA) in Zambian infants. Subjects and methods: Ninety-one women and their normal birth weight (NBW) infants were followed bi-monthly during the first 6 months of life, and iron status, food intake, malaria parasitaemia and growth were monitored. At 4 months, the infants were divided into two groups, and the data were analysed according to whether or not they were exclusively breastfed. Results: Almost two-third of infants were born with low iron stores as defined by ZPP levels, and this proportion increased with age. Over 50% had developed IDA by 6 months. Exclusive breastfeeding at 4 months could be a protective factor for IDA (odds ratio (OR): 0.2; 95% confidence interval (CI): 0.0-1.1). Exclusively breastfed infants had higher haemoglobin values at 4 and 6 months (mean difference 0.6; 95% CI: 0.1-1.2 g/dl and mean difference 0.9; 95% CI: 0.2-1.7 g/dl, respectively), compared with infants with early complementary feeding. In univariate analysis, past or chronic placental malaria appeared to be a predictor of IDA at 4 and 6 months, but the significance was lost in multivariate analysis. Conclusions: Zambian NBW infants are born with low iron stores and have a high risk to develop IDA in the first 6 months of life. Continuation of exclusive breastfeeding after 4 months is associated with a reduction of anaemia. The effect of placental malaria infection on increased risk of infant IDA could not be proven.

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Section: Definitionsmentioning

confidence: 99%

“…Raised ZPP levels indicate incomplete iron incorporation into protoporphyrin, as zinc substitutes for iron when stores are low. ZPP is regarded as a sensitive indicator of iron deficiency (Rettmer et al, 1999;Juul et al, 2003;Miller et al, 2003;Kling, 2006;Lott et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

A cohort study of haemoglobin and zinc protoporphyrin levels in term Zambian infants: effects of iron stores at birth, complementary food and placental malaria

et al. 2007

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“…Because reticulocyte indices are not universally available, whole blood ZnPP/H ratios are simple, cost-effective and require minimal sample volume when screening iron status of premature infants (9, 10). Ratios are directly measured by two commercially available hematofluorometers on drops of blood with minimal cost (34, 35).…”

Section: Discussionmentioning

confidence: 99%

“…The intent of the third, at-risk group was to obtain cord blood from term ethnic minority and Caucasian mothers exhibiting intermediate iron status. From the at-risk group, we defined a mild ID subset with cord plasma ferritin values in the lowest quartile of our samples, but normal cord whole blood ZnPP/H (10). The fourth, premature group included cord blood from newborns with birth weight less than 1500 g, but without known impairment of iron status by maternal diabetes or growth restriction.…”

Section: Methodsmentioning

confidence: 99%

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Reticulocyte Enrichment of Zinc Protoporphyrin/Heme Discriminates Impaired Iron Supply During Early Development

et al. 2008

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ABSTRACT:In infants and children, elevated whole blood zinc protoporphyrin/heme (ZnPP/H) measures iron-deficient (ID) erythropoiesis. Because immature erythrocytes are less dense than mature erythrocytes, we hypothesized that the sensitivity of ZnPP/H is improved if measured in the least dense cells. Blood was collected from control suckling, mildly and severely ID suckling rats. Cord blood was collected after uncomplicated pregnancies (control), diabetic pregnancies (severe ID) and after pregnancies at-risk for iron deficiency (mild ID). ZnPP/H was measured before and after a two-step density centrifugation to obtain the lightest 6.25% of erythrocyte (top fraction). The difference between whole blood and top fraction was defined as ⌬ZnPP/H. In rats, although the whole or top ZnPP/H differed by postnatal age, ⌬ZnPP/H was greatest after the interval with least body iron accrual. In either rats or humans with mild ID, whole blood ZnPP/H was similar to, but ⌬ZnPP/H was greater than controls. In rats and newborn humans, ⌬ZnPP/H is more sensitive than whole blood ZnPP/H in identifying conditions associated with impaired erythrocyte iron delivery and may become a useful tool in measuring erythrocyte iron incorporation in early development. T here is need for a sensitive clinical index of iron-deficient (ID) erythropoiesis in growing premature infants. In premature infants, clinical practices, such as conservative transfusion criteria and erythropoietin therapy may deplete tenuous iron stores (1-4). When iron supply is limited, zinc replaces iron in the protoporphyrin IX ring to form zinc protoporphyrin (ZnPP) (5). An increased ratio of whole blood ZnPP-to-heme (ZnPP/H) reflects impaired erythrocyte iron incorporation (5,6). In older infants, whole blood zinc protoporphyrin/heme (ZnPP/H) is a more sensitive indicator of early, preanemic iron deficiency than Hb or ferritin (7). Whole blood ZnPP/H from cord blood or ill newborns also reflects iron status (4,8). ZnPP/H is higher in newborns born small for dates and offspring of mothers with insulin-treated diabetes (IDM), two conditions commonly exhibiting severely impaired tissue iron content, i.e., severe iron deficiency (severe ID) at birth (4,8). In premature infants, whole blood ZnPP/H falls in response to iron therapy (9) or with indirect delivery of iron via transfusion (3). In premature infants, whole blood ratios are inversely related to gestation (8), a clinical disadvantage because of gestation-based normal values are necessary to guide interpretation (4,8 -10).In mild ID, when Hb levels have not yet fallen, employing a more sensitive test of iron incorporation would be useful to facilitate earlier treatment. When iron demands are great and iron is limited, testing the iron status of reticulocytes, the most recently produced erythrocytes, would decrease the number of false negative assessments and improve the sensitivity of ZnPP/H to detect impaired iron incorporation. Previous work supports that measuring iron incorporation into reticulocytes (reticulocyte Hb,...

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Macro and Micronutrients

Greer¹

2008

Gastroenterology and Nutrition: Neonatology Questions and Controversies

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The Zinc Protoporphyrin/Heme Ratio in Premature Infants: Has it Found its Place?

Cited by 10 publications

References 17 publications

A cohort study of haemoglobin and zinc protoporphyrin levels in term Zambian infants: effects of iron stores at birth, complementary food and placental malaria

A cohort study of haemoglobin and zinc protoporphyrin levels in term Zambian infants: effects of iron stores at birth, complementary food and placental malaria

Reticulocyte Enrichment of Zinc Protoporphyrin/Heme Discriminates Impaired Iron Supply During Early Development

Macro and Micronutrients

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