Iron assessment tests: transferrin receptor vis-à-vis zinc protoporphyrin

Comparison of Current World Health Organization Guidelines with Physiologically Based Serum Ferritin Thresholds for Iron Deficiency in Healthy Young Children and Nonpregnant Women Using Data from the Third National Health and Nutrition Examination Survey

BACKGROUND

Current WHO serum ferritin (SF) thresholds for iron deficiency (ID) in children (<12 μg/L) and women (<15 μg/L) are derived from expert opinion based on radiometric assays in use decades ago. Using a contemporary immunoturbidimetry assay, higher thresholds (children, <20 μg/L; women, <25 μg/L) were identified from physiologically based analyses.

OBJECTIVE

We examined relationships of SF measured using an immunoradiometric assay from the era of expert opinion with 2 independently measured indicators of ID, hemoglobin (Hb) and erythrocyte zinc protoporphyrin (eZnPP), using data from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). The SF at which circulating Hb begins to decrease and eZnPP begins to increase provides a physiological basis for identifying the onset of iron-deficient erythropoiesis.

METHODS

We analyzed NHANES III cross-sectional data from 2616 apparently healthy children, aged 12-59 mo, and 4639 apparently healthy nonpregnant women, aged 15-49 y. We used restricted cubic spline regression models to determine SF thresholds for ID.

RESULTS

SF thresholds identified by Hb and eZnPP did not differ significantly in children, 21.2 μg/L (95% confidence interval: 18.5, 26.5) and 18.7 μg/L (17.9, 19.7), and, in women, were similar although significantly different, 24.8 μg/L (23.4, 26.9) and 22.5 μg/L (21.7, 23.3).

CONCLUSIONS

These NHANES results suggest that physiologically based SF thresholds are higher than the thresholds from expert opinion established during the same era. SF thresholds found using physiological indicators detect the onset of iron-deficient erythropoiesis, whereas the WHO thresholds identify a later, more severe stage of ID.

Effectiveness of zinc protoporphyrin/heme ratio and ferritin for assessing iron status in preterm infants

BACKGROUND

Since iron is crucial for many tissue processes, we, therefore, aimed to assess ferritin and the zinc protoporphyrin to heme ratio (ZnPP/H) as indicators of iron status in preterm newborns, particularly during certain inflammatory episodes.

METHODS

From 170 preterm babies, paired ferritin and ZnPP/H measurements were collected twice (on the first postnatal day and six weeks later). To compare these measures and assess the impact of anemia, sepsis, and packed red blood cell transfusion (PRBT), three different scenarios were considered.

RESULTS

Compared to the non-anemic group, the anemic patients' serum ferritin level was considerably lower (p = 0.044), whereas the anemic patients' ZPP/H ratio was significantly greater (p < 0.001). In neonates with sepsis, ferritin levels were considerably greater in both anemic and non-anemic septic neonates compared to neonates without sepsis (p < 0.001 for each). Regarding ZPP/H ratio, no appreciable variations were found between the two groups. In addition, serum ferritin significantly increased following each PRBT (p < 0.001 for each). As a result of each PRBT, the ZPP/H ratio considerably decreased (p < 0.001).

CONCLUSION

As a measure of iron status during particular inflammatory processes like infection and PRBT, ZnPP/H may be more accurate.

Zinc protoporphyrin levels in COVID-19 are indicative of iron deficiency and potential predictor of disease severity

Background

Coronavirus disease (COVID-19) has a severe impact on all aspects of patient care. Among the numerous biomarkers of potential validity for diagnostic and clinical management of COVID-19 are biomarkers at the interface of iron metabolism and inflammation.

Methods

The follow-up study included 54 hospitalized patients with laboratory-confirmed COVID-19 with a moderate and severe/critical form of the disease. Iron deficiency specific biomarkers such as iron, ferritin, transferrin receptor, hepcidin, and zinc protoporphyrin (ZnPP) as well as relevant markers of inflammation were evaluated twice: in the first five days when the patient was admitted to the hospital and during five to 15 days; and their validity to diagnose iron deficiency was further assessed. The regression and Receiver Operating Characteristics (ROC) analyses were performed to evaluate the prognosis and determine the probability for predicting the severity of the disease in the first five days of COVID-19.

Results

Based on hemoglobin values, anemia was observed in 21 of 54 patients. Of all iron deficiency anemia-related markers, only ZnPP was significantly elevated (P<0.001) in the anemic group. When patients were grouped according to the severity of disease, slight differences in hemoglobin or other anemia-related parameters could be observed. However, the levels of ZnPP were significantly increased in the severely ill group of patients. The ratio of ZnPP to lymphocyte count (ZnPP/L) had a discrimination power stronger than the neutrophil to lymphocyte count ratio (N/L) to determine disease severity. Additionally, only two markers were independently associated with the severity of COVID-19 in logistic regression analysis; D-dimer (OR (5.606)(95% CI 1.019–30.867)) and ZnPP/L ratio (OR (74.313) (95% CI 1.081–5108.103)).

Conclusions

For the first time ZnPP in COVID-19 patients were reported in this study. Among all iron-related markers tested, ZnPP was the only one that was associated with anemia as based on hemoglobin. The increase in ZnPP might indicate that the underlying cause of anemia in COVID-19 patients is not only due to the inflammation but also of nutritional origin. Additionally, the ZnPP/L ratio might be a valid prognostic marker for the severity of COVID-19.

Serum or plasma ferritin concentration as an index of iron deficiency and overload

BACKGROUND

Reference standard indices of iron deficiency and iron overload are generally invasive, expensive, and can be unpleasant or occasionally risky. Ferritin is an iron storage protein and its concentration in the plasma or serum reflects iron stores; low ferritin indicates iron deficiency, while elevated ferritin reflects risk of iron overload. However, ferritin is also an acute-phase protein and its levels are elevated in inflammation and infection. The use of ferritin as a diagnostic test of iron deficiency and overload is a common clinical practice.

OBJECTIVES

To determine the diagnostic accuracy of ferritin concentrations (serum or plasma) for detecting iron deficiency and risk of iron overload in primary and secondary iron-loading syndromes.

SEARCH METHODS

We searched the following databases (10 June 2020): DARE (Cochrane Library) Issue 2 of 4 2015, HTA (Cochrane Library) Issue 4 of 4 2016, CENTRAL (Cochrane Library) Issue 6 of 12 2020, MEDLINE (OVID) 1946 to 9 June 2020, Embase (OVID) 1947 to week 23 2020, CINAHL (Ebsco) 1982 to June 2020, Web of Science (ISI) SCI, SSCI, CPCI-exp & CPCI-SSH to June 2020, POPLINE 16/8/18, Open Grey (10/6/20), TRoPHI (10/6/20), Bibliomap (10/6/20), IBECS (10/6/20), SCIELO (10/6/20), Global Index Medicus (10/6/20) AIM, IMSEAR, WPRIM, IMEMR, LILACS (10/6/20), PAHO (10/6/20), WHOLIS 10/6/20, IndMED (16/8/18) and Native Health Research Database (10/6/20). We also searched two trials registers and contacted relevant organisations for unpublished studies.

SELECTION CRITERIA

We included all study designs seeking to evaluate serum or plasma ferritin concentrations measured by any current or previously available quantitative assay as an index of iron status in individuals of any age, sex, clinical and physiological status from any country.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. We designed the data extraction form to record results for ferritin concentration as the index test, and bone marrow iron content for iron deficiency and liver iron content for iron overload as the reference standards. Two other authors further extracted and validated the number of true positive, true negative, false positive, false negative cases, and extracted or derived the sensitivity, specificity, positive and negative predictive values for each threshold presented for iron deficiency and iron overload in included studies. We assessed risk of bias and applicability using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 tool. We used GRADE assessment to enable the quality of evidence and hence strength of evidence for our conclusions.

MAIN RESULTS

Our search was conducted initially in 2014 and updated in 2017, 2018 and 2020 (10 June). We identified 21,217 records and screened 14,244 records after duplicates were removed. We assessed 316 records in full text. We excluded 190 studies (193 records) with reasons and included 108 studies (111 records) in the qualitative and quantitative analysis. There were 11 studies (12 records) that we screened from the last search update and appeared eligible for a future analysis. We decided to enter these as awaiting classification. We stratified the analysis first by participant clinical status: apparently healthy and non-healthy populations. We then stratified by age and pregnancy status as: infants and children, adolescents, pregnant women, and adults. Iron deficiency We included 72 studies (75 records) involving 6059 participants. Apparently healthy populations Five studies screened for iron deficiency in people without apparent illness. In the general adult population, three studies reported sensitivities of 63% to 100% at the optimum cutoff for ferritin, with corresponding specificities of 92% to 98%, but the ferritin cutoffs varied between studies. One study in healthy children reported a sensitivity of 74% and a specificity of 77%. One study in pregnant women reported a sensitivity of 88% and a specificity of 100%. Overall confidence in these estimates was very low because of potential bias, indirectness, and sparse and heterogenous evidence. No studies screened for iron overload in apparently healthy people. People presenting for medical care There were 63 studies among adults presenting for medical care (5042 participants). For a sample of 1000 subjects with a 35% prevalence of iron deficiency (of the included studies in this category) and supposing a 85% specificity, there would be 315 iron-deficient subjects correctly classified as having iron deficiency and 35 iron-deficient subjects incorrectly classified as not having iron deficiency, leading to a 90% sensitivity. Thresholds proposed by the authors of the included studies ranged between 12 to 200 µg/L. The estimated diagnostic odds ratio was 50. Among non-healthy adults using a fixed threshold of 30 μg/L (nine studies, 512 participants, low-certainty evidence), the pooled estimate for sensitivity was 79% with a 95% confidence interval of (58%, 91%) and specificity of 98%, with a 95% confidence interval of (91%, 100%). The estimated diagnostic odds ratio was 140, a relatively highly informative test. Iron overload We included 36 studies (36 records) involving 1927 participants. All studies concerned non-healthy populations. There were no studies targeting either infants, children, or pregnant women. Among all populations (one threshold for males and females; 36 studies, 1927 participants, very low-certainty evidence): for a sample of 1000 subjects with a 42% prevalence of iron overload (of the included studies in this category) and supposing a 65% specificity, there would be 332 iron-overloaded subjects correctly classified as having iron overload and 85 iron-overloaded subjects incorrectly classified as not having iron overload, leading to a 80% sensitivity. The estimated diagnostic odds ratio was 8.

AUTHORS' CONCLUSIONS

At a threshold of 30 micrograms/L, there is low-certainty evidence that blood ferritin concentration is reasonably sensitive and a very specific test for iron deficiency in people presenting for medical care. There is very low certainty that high concentrations of ferritin provide a sensitive test for iron overload in people where this condition is suspected. There is insufficient evidence to know whether ferritin concentration performs similarly when screening asymptomatic people for iron deficiency or overload.

Zinc Protoporphyrin Is a Reliable Marker of Functional Iron Deficiency in Patients with Inflammatory Bowel Disease

Iron deficiency (ID) is a common manifestation of inflammatory bowel disease (IBD), arising primarily due to chronic inflammation and/or blood loss. There is no gold standard for ID diagnosis, which is often complicated by concomitant inflammation. Zinc protoporphyrin (ZnPP) correlates with parameters of iron homeostasis and has been identified as a promising marker for ID, irrespective of inflammation. We investigated the diagnostic performance of ZnPP in ID, iron deficiency anemia, anemia of chronic disease and mixed anemia in a cross-sectional study in 130 patients with IBD. Different parameters were compared by receiver operator characteristic (ROC) analysis as detectors of iron-restricted erythropoiesis (IRE). IRE was detected in 91 patients (70.0%); fifty-nine (64.8%) had absolute ID and 23 (25.4%) functional ID. When inflammation was present, ZnPP was a more reliable sole biomarker of IRE than MCV, transferrin saturation (TSAT) or ferritin (AUC; 0.855 vs. 0.763, 0.834% and 0.772, respectively). The specificity of TSAT was significantly lower than ZnPP when inflammation was present (38% vs. 71%, respectively). We conclude that ZnPP is a reliable biomarker of functional ID in patients with IBD and more dependable than ferritin or TSAT, which are influenced by chronic inflammation. We propose that ZnPP may also have utility in patients with other chronic diseases.

Effect of locally produced complementary foods on fat-free mass, linear growth, and iron status among Kenyan infants: A randomized controlled trial

The impact of quality complementary food products on infant growth and body composition has not been adequately investigated. This study evaluated the effect on fat-free mass (FFM) accrual, linear growth, and iron status of locally produced complementary food products comparing to a standard product. In a randomized, double-blind trial, 499 infants at 6 months received nine monthly rations of (a) WinFood Classic (WFC) comprising germinated amaranth (71%), maize (10.4%), small fish (3%), and edible termites (10%); (b) WinFood Lite (WFL) comprising germinated amaranth (82.5%), maize (10.2%), and multimicronutrient premix; or (c) fortified corn-soy blend plus (CSB+). Primary outcomes were changes in FFM, length, and plasma ferritin and transferrin receptors (TfR). FFM was determined using deuterium dilution. Analysis was by intention to treat, based on available cases. Compared with CSB+, there were no differences in change from 6 to 15 months in FFM for WFC 0.0 kg (95% CI [-0.30, 0.29]) and WFL 0.03 kg (95% CI [-0.25, 0.32]) and length change for WFC -0.3 cm (95% CI [-0.9, 0.4]) and WFL -0.3 cm (95% CI [-0.9, 0.3]). TfR increased in WFC group 3.3 mg L^-1 (95% CI [1.7, 4.9]) and WFL group 1.7 mg L^-1 (95% CI [0.1, 3.4]) compared with CSB+. Compared with the increase in Hb in CSB+ group, there was a reduction in Hb in WFC of -0.9 g dl^-1 (95% CI [-1.3, -0.5]) and a lower increase in WFL -0.4 g dl^-1 (95% CI [-0.8, 0.0]). In conclusion, the tested WinFoods had the same effect on FFM and length as CSB+, whereas Hb and iron status decreased, suggesting inhibited iron bioavailability from the amaranth-based WinFoods.

Best Practices for Conducting Observational Research to Assess the Relation between Nutrition and Bone: An International Working Group Summary

Diet is a modifiable factor that can affect bone strength and integrity, and the risk of fractures. Currently, a hierarchy of scientific evidence contributes to our understanding of the role of diet on bone health and fracture risk. The strength of evidence is generally based on the type of study conducted, the quality of the methodology employed, the rigor and integrity of the data collected and analysis plan, and the transparency and completeness of the results. Randomized controlled trials (RCTs) are considered to be the gold standard from a clinical research paradigm, but there is a dearth of high-quality diet-related intervention trials with bone as the primary outcome, forcing the use of observational research to inform research and clinical practices. However, for observational research to be of the most utility, standardization and optimization of the study design, accurate and reliable measurement of key variables, and appropriate data analysis and data reporting are paramount. Although there have been recommendations made in relation to RCTs in the field of nutrition, no clear rubric exists for best practices in conducting observational research with regard to nutrition and bone health. Therefore, the purpose of this paper is to describe the best practices and considerations for designing, conducting, analyzing, interpreting, and reporting observational research specifically for understanding the role of nutrition in bone health, amassed by a global panel of scientific experts with strengths in bone, nutrition epidemiology, physical activity, public health, clinical and translational trials, and observational study methods. The global panel of scientific experts represents the leadership and selected participants from the 10th annual International Symposium for the Nutritional Aspects of Osteoporosis. The topics selected and best practices presented reflect expert opinion and areas of scientific expertise of the authors rather than a systematic or comprehensive literature review or professional reporting guidelines.

Non-invasive measurement of erythrocyte zinc protoporphyrin in children

BACKGROUND

Reliable screening for iron deficiency (ID) has required a blood sample and cost-intensive laboratory measurements. A novel method to non-invasively measure erythrocyte zinc protoporphyrin (ZnPP), an established marker for ID, is evaluated in children.

METHODS

ZnPP was determined non-invasively by fluorescence measurements on the wet vermillion of the lower lip in 99 hospitalized children aged 9 months to 5 years. For comparison, conventional ID parameters and ZnPP were determined from blood samples.

RESULTS

The non-invasively measured ZnPP values had limits of agreement (LoA) of 14 µmol ZnPP/mol heme (95% confidence interval: 9-20) compared to fluorescence measurements directly in blood. Repeated high-performance liquid chromatography reference determinations had comparable LoA of 14 µmol ZnPP/mol heme (9-17). Non-invasive ZnPP measurements had sensitivity and specificity of 67% (39-88%) and 97% (91-99%), and negative and positive predictive value of 94% (90-97%) and 80% (55-93%), for detecting ID as defined by the soluble transferrin receptor (sTfR). In groups with more severe ID as defined by serum ferritin and sTfR, higher ZnPP values were found, with the highest ZnPP values for the group with ID anemia.

CONCLUSION

Non-invasive ZnPP measurements are reliably feasible in children. The simple and fast method has the potential to enable wide-spread screening for ID.

Maternal and Infant Supplementation with Small-Quantity Lipid-Based Nutrient Supplements Increases Infants' Iron Status at 18 Months of Age in a Semiurban Setting in Ghana: A Secondary Outcome Analysis of the iLiNS-DYAD Randomized Controlled Trial

Background

Interventions are needed to address iron deficiency in low-income settings.

Objective

This secondary outcome analysis aimed to compare the hemoglobin (Hb) and iron status [zinc protoporphyrin (ZPP)] of children born to women enrolled in the iLiNS-DYAD trial in Ghana.

Methods

Women ≤20 wk pregnant (n = 1320) were assigned to receive 60 mg Fe/d and 400 µg folic acid/d until delivery and placebo thereafter, and no supplementation for infants (IFA group); or multiple micronutrients containing 20 mg Fe/d until 6 mo postpartum and no supplementation for infants (MMN); or small-quantity lipid-based nutrient supplements (SQ-LNSs) containing 20 mg Fe/d until 6 mo postpartum, and SQ-LNSs for infants from 6 to 18 mo of age (LNS). We compared infants' Hb (g/L) and ZPP (µmol/mol heme) at 6 and 18 mo of age.

Results

At 6 mo of age, groups did not differ in mean ± SD Hb (overall: 113 ± 9.9 g/L) or geometric mean (95% CI) ZPP [overall: 62.6 (60.6, 64.7)]. At 18 mo of age, mean ± SD Hb (overall: 112 ± 10.4 g/L) did not differ significantly between groups, whereas geometric mean (95% CI) ZPP was lower (P = 0.031) in the LNS group [53.9 (50.7, 57.3)] than the IFA [60.4 (56.7, 64.3)] but not the MMN [58.8 (55.6, 62.2)] group. Further, the LNS group, compared with the IFA and MMN groups combined, had a lower prevalence of elevated (>70) ZPP (27.5% compared with 35%; P = 0.02) and a marginally lower prevalence of anemia (38.7% compared with 44.9%; P = 0.06). These results generally remained unchanged when controlling for prespecified covariates or correcting for inflammation.

Conclusions

In this setting, providing SQ-LNSs or multiple micronutrients with 20 mg Fe/d, compared with iron (60 mg/d) and folic acid, to pregnant women does not affect their infants' Hb or iron status at 6 mo of age, but maternal and infant supplementation with SQ-LNSs increases infants' iron status at 18 mo of age. This trial was registered at clinicaltrials.gov as NCT00970866.

Dysregulated iron metabolism in polycythemia vera: etiology and consequences

Polycythemia vera (PV) is a chronic myeloproliferative neoplasm. Virtually all PV patients are iron deficient at presentation and/or during the course of their disease. The co-existence of iron deficiency and polycythemia presents a physiological disconnect. Hepcidin, the master regulator of iron metabolism, is regulated by circulating iron levels, erythroblast secretion of erythroferrone, and inflammation. Both decreased circulating iron and increased erythroferrone levels, which occur as a consequence of erythroid hyperplasia in PV, are anticipated to suppress hepcidin and enable recovery from iron deficiency. Inflammation which accompanies PV is likely to counteract hepcidin suppression, but the relatively low serum ferritin levels observed suggest that inflammation is not a major contributor to the dysregulated iron metabolism. Furthermore, potential defects in iron absorption, aberrant hypoxia sensing and signaling, and frequency of bleeding to account for iron deficiency in PV patients have not been fully elucidated. Insufficiently suppressed hepcidin given the degree of iron deficiency in PV patients strongly suggests that disordered iron metabolism is an important component of the pathobiology of PV. Normalization of hematocrit levels using therapeutic phlebotomy is the most common approach for reducing the incidence of thrombotic complications, a therapy which exacerbates iron deficiency, contributing to a variety of non-hematological symptoms. The use of cytoreductive therapy in high-risk PV patients frequently works more effectively to reverse PV-associated symptoms in iron-deficient relative to iron-replete patients. Lastly, differences in iron-related parameters between PV patients and mice with JAK2 V617F and JAK2 exon 12 mutations suggest that specific regions in JAK2 may influence iron metabolism by nuanced changes of erythropoietin receptor signaling. In this review, we comprehensively discuss the clinical consequences of iron deficiency in PV, provide a framework for understanding the potential dysregulation of iron metabolism, and present a rationale for additional therapeutic options for iron-deficient PV patients.

Utility of zinc protoporphyrin in management of whole blood donors

BACKGROUND

Deferral for low hemoglobin (Hb) increases the likelihood that donors do not return for future donations. Zinc protoporphyrin (ZPP) has been described as a sensitive marker of iron-deficient erythropoiesis, before Hb decreases. It is a relatively cheap, rapid, and easy-to-perform measurement in a drop of whole blood. To assess the utility of ZPP measurement in donor management we examined whether ZPP and Hb levels among first-time donors differ from repeat donors. We further explored whether ZPP increases over subsequent donations at a donor population level and whether increasing ZPP levels coincide with decreasing Hb levels and donor deferral.

STUDY DESIGN AND METHODS

We included first-time (n = 4983) and repeat (n = 3533) whole blood donors from the ZPP and Iron in the Netherlands Cohort (ZINC) study. ZPP and Hb were measured at each subsequent donation during a 4-year period after inclusion in the study.

RESULTS

Median ZPP levels were higher in repeat than in first-time donors. In first-time donors, especially women, ZPP levels were increased with a corresponding decline in Hb levels over subsequent donations. ZPP levels were increased among first-time donors deferred for low Hb.

CONCLUSION

Our results suggest that adding ZPP to Hb measurements in the daily blood collection setting, especially for first-time donors and first-time female donors may add to the identification of a donor subpopulation with low functional iron stores.

THE PREVALENCE OF CELIAC DISEASE IN PATIENTS WITH IRON-DEFICIENCY ANEMIA IN CENTER AND SOUTH AREA OF IRAN

BACKGROUND

Celiac disease is an immune-mediated enteropathy due to a permanent sensitivity to gluten in genetically susceptible people. Iron-deficiency anemia is the most widely experienced anemia in humans. Iron-deficiency anemia additionally is a common extra intestinal manifestation of celiac disease.

OBJECTIVE

To investigate correlation between tTg levels and histological alterations and then to determine the prevalence of celiac disease in Center and South area patients of Iran with iron deficiency anemia.

METHODS

A total of 402 patients aged 12-78 years who presented with iron-deficiency anemia were included in this study. Hemoglobin, mean corpuscular volume and serum ferritin were determined. Venous blood samples for anti-tissue transglutaminase antibody immunoglobuline A and G were obtained from these patients. Upper gastrointestinal endoscopy was recommended to patients who had positive serology.

RESULTS

Of 402 patients with iron-deficiency anemia, 42 (10.4%) had positive serology for celiac disease. The small intestine biopsy of all patients with positive serology showed pathological changes (Marsh I, II & III). There was not significant difference in the mean hemoglobin level between iron-deficiency anemia patients with celiac disease and without celiac disease, duodenal biopsy results did not show significant relationship between the severity of pathological changes and levels of anti-tTG IgG (P -value: 0/869) but significant relationship was discovered between pathological changes and levels of anti-tTG IgA (P -value: 0/004).

CONCLUSION

Screening of celiac disease by anti-tissue transglutaminase antibody should be completed as a routine investigation in patients with iron-deficiency anemia. Also physicians must consider celiac disease as a possible reason of anemia in all patients with iron deficiency anemia.

Nutritional Aspects of Essential Trace Elements in Oral Health and Disease: An Extensive Review

Human body requires certain essential elements in small quantities and their absence or excess may result in severe malfunctioning of the body and even death in extreme cases because these essential trace elements directly influence the metabolic and physiologic processes of the organism. Rapid urbanization and economic development have resulted in drastic changes in diets with developing preference towards refined diet and nutritionally deprived junk food. Poor nutrition can lead to reduced immunity, augmented vulnerability to various oral and systemic diseases, impaired physical and mental growth, and reduced efficiency. Diet and nutrition affect oral health in a variety of ways with influence on craniofacial development and growth and maintenance of dental and oral soft tissues. Oral potentially malignant disorders (OPMD) are treated with antioxidants containing essential trace elements like selenium but even increased dietary intake of trace elements like copper could lead to oral submucous fibrosis. The deficiency or excess of other trace elements like iodine, iron, zinc, and so forth has a profound effect on the body and such conditions are often diagnosed through their early oral manifestations. This review appraises the biological functions of significant trace elements and their role in preservation of oral health and progression of various oral diseases.

Iron deficiency anaemia

Anaemia affects roughly a third of the world's population; half the cases are due to iron deficiency. It is a major and global public health problem that affects maternal and child mortality, physical performance, and referral to health-care professionals. Children aged 0-5 years, women of childbearing age, and pregnant women are particularly at risk. Several chronic diseases are frequently associated with iron deficiency anaemia--notably chronic kidney disease, chronic heart failure, cancer, and inflammatory bowel disease. Measurement of serum ferritin, transferrin saturation, serum soluble transferrin receptors, and the serum soluble transferrin receptors-ferritin index are more accurate than classic red cell indices in the diagnosis of iron deficiency anaemia. In addition to the search for and treatment of the cause of iron deficiency, treatment strategies encompass prevention, including food fortification and iron supplementation. Oral iron is usually recommended as first-line therapy, but the most recent intravenous iron formulations, which have been available for nearly a decade, seem to replenish iron stores safely and effectively. Hepcidin has a key role in iron homoeostasis and could be a future diagnostic and therapeutic target. In this Seminar, we discuss the clinical presentation, epidemiology, pathophysiology, diagnosis, and acute management of iron deficiency anaemia, and outstanding research questions for treatment.

Non-invasive detection of iron deficiency by fluorescence measurement of erythrocyte zinc protoporphyrin in the lip

Worldwide, more individuals have iron deficiency than any other health problem. Most of those affected are unaware of their lack of iron, in part because detection of iron deficiency has required a blood sample. Here we report a non-invasive method to optically measure an established indicator of iron status, red blood cell zinc protoporphyrin, in the microcirculation of the lower lip. An optical fibre probe is used to illuminate the lip and acquire fluorescence emission spectra in ∼1 min. Dual-wavelength excitation with spectral fitting is used to distinguish the faint zinc protoporphyrin fluorescence from the much greater tissue background fluorescence, providing immediate results. In 56 women, 35 of whom were iron-deficient, the sensitivity and specificity of optical non-invasive detection of iron deficiency were 97% and 90%, respectively. This fluorescence method potentially provides a rapid, easy to use means for point-of-care screening for iron deficiency in resource-limited settings lacking laboratory infrastructure.

Iron deficiency, the most common health problem in the world, has required a blood test for diagnosis. Here, the authors show that iron deficiency can be detected non-invasively and quickly by measuring the fluorescence of red blood cell zinc protoporphyrin in the microcirculation of the lip.

A Review of Cutoffs for Nutritional Biomarkers

The nutritional status of an individual or population needs to be assessed through valid and reliable biomarkers. Cutoffs generally have an underlying relation to health status and are one of the important quantitative criteria against which biomarker outputs are compared. For this reason, cutoffs are integral for surveys, surveillance, screening, interventions, monitoring, and evaluation. Despite their importance, nutritional biomarker cutoffs have not been adequately addressed in the literature. Furthermore, the field has not reached a consensus on which cutoff to use for each biomarker, and different cutoffs are often used for the same biomarkers in published studies. This review provides a comprehensive overview of cutoffs related to nutritional biomarkers and highlights some of the high-priority research gaps and challenges of using micronutrient case studies.

Impact of Fetal-Neonatal Iron Deficiency on Recognition Memory at 2 Months of Age

OBJECTIVE

To assess the effects of fetal-neonatal iron deficiency on recognition memory in early infancy. Perinatal iron deficiency delays or disrupts hippocampal development in animal models and thus may impair related neural functions in human infants, such as recognition memory.

STUDY DESIGN

Event-related potentials were used in an auditory recognition memory task to compare 2-month-old Chinese infants with iron sufficiency or deficiency at birth. Fetal-neonatal iron deficiency was defined 2 ways: high zinc protoporphyrin/heme ratio (ZPP/H > 118 μmol/mol) or low serum ferritin (<75 μg/L) in cord blood. Late slow wave was used to measure infant recognition of mother's voice.

RESULTS

Event related potentials patterns differed significantly for fetal-neonatal iron deficiency as defined by high cord ZPP/H but not low ferritin. Comparing 35 infants with iron deficiency (ZPP/H > 118 μmol/mol) to 92 with lower ZPP/H (iron-sufficient), only infants with iron sufficiency showed larger late slow wave amplitude for stranger's voice than mother's voice in frontal-central and parietal-occipital locations, indicating the recognition of mother's voice.

CONCLUSIONS

Infants with iron sufficiency showed electrophysiological evidence of recognizing their mother's voice, whereas infants with fetal-neonatal iron deficiency did not. Their poorer auditory recognition memory at 2 months of age is consistent with effects of fetal-neonatal iron deficiency on the developing hippocampus.

Oral zinc supplementation decreases the serum iron concentration in healthy schoolchildren: a pilot study

The recognized antagonistic actions between zinc and iron prompted us to study this subject in children. A convenience sample was used. Thirty healthy children between 8 and 9 years of age were studied with the aim of establishing the effect of a 3-mo oral zinc supplementation on iron status. Fifteen individuals were given a placebo (control group), and 15 were given 10 mg Zn/day (experimental group). Blood samples were collected at 0, 60, 120, 180 and 210 min after a 12-h overnight fast, before and after placebo or zinc supplementation. This supplementation was associated with significant improvements in energy, protein, fat, carbohydrate, fiber, calcium, iron, and zinc intake in accordance with the recommendations for age and sex. The basal serum zinc concentration significantly increased after oral zinc supplementation (p < 0.001). However, basal serum iron concentrations and area under the iron curves significantly decreased in the experimental group (p < 0.0001) and remained at the same level throughout the 210-min study. The values obtained for hemoglobin, mean corpuscular volume, ferritin, transferrin, transferrin saturation, ceruloplasmin and total protein were within normal reference ranges. In conclusion, the decrease in serum iron was likely due to the effects of chronic zinc administration, and the decrease in serum iron was not sufficient to cause anemia.

Iron supplementation in premature infants using the zinc protoporphyrin to heme ratio: short- and long-term outcomes

OBJECTIVE

The objective of this study was to determine the effect of incrementally higher doses of iron on the zinc protoporphyrin to heme ratio (ZnPP/H) and serum ferritin, and developmental outcomes in premature infants at risk for iron deficiency.

STUDY DESIGN

Infants eligible for this prospective, randomized blinded trial were between 27 and 30 completed weeks of gestation, older than 1 week of age and tolerating 100 ml kg(-1) per day of enteral feedings. The control group was treated with 2.2 mg kg(-1) per day of ferrous sulfate and the treatment group was treated with 3 to 12 mg kg(-1) per day based on the ZnPP/H. Infants had follow-up with Bayley exams at 6 and 24 months corrected age. Statistical evaluation included Student's t-tests and Fisher's exact test.

RESULT

Eighty-one infants were enrolled (40 control, 41 treatment). The average total iron dose for the control group was 2.2 mg kg(-1) per day and for the treatment group was 10.4 mg kg(-1) per day (P<0.05). The ZnPP/H was not different between the two groups. The ferritin at the end of the study was decreased in the control group but remained stable in the treatment group (control initial 202±109 ng ml(-1), final 168±141 ng ml(-1) (P<0.05); treatment initial 187±131 ng ml(-1), final 176±118 ng ml(-1)). At 24 months, infants with psychomotor development index <85 occurred in 25% of the subjects in the control group and in 7% of subjects in the treatment group in a post hoc analysis (odds ratio, 4.2; 95% confidence interval, 0.7 to 43, P=0.07).

CONCLUSION

The ZnPP/H may not be a reliable marker of iron status when used in a short period of time during iron supplementation. Infants treated with a lower dose of ferrous sulfate had a decreasing serum ferritin and a trend toward increased motor delays at 24 months.

Erythropoiesis and the approach to anemia in premature infants

OBJECTIVE

To review causes of anemia in preterm infants and to suggest potential preventive measures.

METHODS

Data for this review is obtained from review of the literature.

RESULTS

An approach to investigating and treating causes of neonatal anemia is outlined.

CONCLUSIONS

Clinical practices can significantly impact anemia in premature infants. Delayed cord clamping, decreasing phlebotomy loss and optimizing nutritional support are practices that may decrease the severity of anemia, thereby decreasing the need for transfusions or erythropoietin treatment.

Zinc protoporphyrin-to-heme ratios in high-risk and preterm infants

OBJECTIVES

To refine the reference range for the zinc protoporphyrin-to-heme ratio (ZnPP/H) of preterm infants, we assessed the impact of maternal risk factors on ZnPP/H and evaluated the impact of changes in iron supplementation on iron status.

STUDY DESIGN

The reference range for neonatal ZnPP/H was refined using prospective data from 31 reference infants ≤ 35 weeks' postmenstrual age (PMA) plus retrospective data from 51 infants <30 weeks' PMA, and 59 infants 30-40 weeks' PMA. Cord blood and first week of life values were compared when both were available. The impact of maternal risk factors was assessed by examining prospectively collected ZnPP/H from 48 high-risk infants. The effect of changing iron supplementation guidelines was evaluated by retrospective chart review of serial ZnPP/H from 194 infants.

RESULTS

Cord ZnPP/H was lower at 30-35 weeks' gestation than at 24-26 weeks' gestation (P = .01). Cord ZnPP/H values from insulin-dependent diabetic mothers were elevated compared with reference values. Changing the iron supplementation protocol was not associated with improved ZnPP/H measurements.

CONCLUSIONS

Cord blood and postnatal reference ranges for ZnPP/H are defined. Iron balance depends on a complex interaction of prenatal and postnatal factors.

Optimal management of iron deficiency anemia due to poor dietary intake

Iron is necessary for the normal development of multiple vital processes. Iron deficiency (ID) may be caused by several diseases, even by physiological situations that increase requirements for this mineral. One of its possible causes is a poor dietary iron intake, which is infrequent in developed countries, but quite common in developing areas. In these countries, dietary ID is highly prevalent and comprises a real public health problem and a challenge for health authorities. ID, with or without anemia, can cause important symptoms that are not only physical, but can also include a decreased intellectual performance. All this, together with a high prevalence, can even have negative implications for a community’s economic and social development. Treatment consists of iron supplements. Prevention of ID obviously lies in increasing the dietary intake of iron, which can be difficult in developing countries. In these regions, foods with greater iron content are scarce, and attempts are made to compensate this by fortifying staple foods with iron. The effectiveness of this strategy is endorsed by multiple studies. On the other hand, in developed countries, ID with or without anemia is nearly always associated with diseases that trigger a negative balance between iron absorption and loss. Its management will be based on the treatment of underlying diseases, as well as on oral iron supplements, although these latter are limited by their tolerance and low potency, which on occasions may compel a change to intravenous administration. Iron deficiency has a series of peculiarities in pediatric patients, in the elderly, in pregnant women, and in patients with dietary restrictions, such as celiac disease.

Efficacy of a microencapsulated iron pyrophosphate-fortified fruit juice: a randomised, double-blind, placebo-controlled study in Spanish iron-deficient women

Fe-deficiency anaemia is a worldwide health problem. We studied the influence of consuming an Fe-fortified fruit juice on Fe status in menstruating women. A randomised, double-blind, placebo-controlled study of 16 weeks of duration was performed. Subjects were randomised into two groups: the P group (n 58) or the F group (n 64), and consumed, as a supplement to their usual diet, 500 ml/d of a placebo fruit juice or an Fe-fortified fruit juice, respectively. The Fe-fortified fruit juice, containing microencapsulated iron pyrophosphate, provided 18 mg Fe/d (100 % of the RDA). At baseline and monthly, dietary intake, body weight and Fe parameters were determined: total erythrocytes, haematocrit, mean corpuscular volume (MCV), red blood cell distribution width (RDW), Hb, serum Fe, serum ferritin, serum transferrin, transferrin saturation, soluble transferrin receptor (sTfR) and zinc protoporphyrin (ZnPP). The fruit juice consumption involved increased intake of carbohydrates and vitamin C, and increased BMI within normal limits. Ferritin was higher in the F group after week 4 (P < 0·05) and became 80 % higher than in the P group after week 16 (P < 0·001), and transferrin decreased in the F group compared with the P group after week 4 (P < 0·001). RDW was higher at weeks 4 and 8 in the F group compared with the P group (P < 0·05). Transferrin saturation increased after week 8, and haematocrit, MCV and Hb increased after week 12, in the F group compared with the P group. Serum Fe did not change. sTfR and ZnPP decreased in the F group at week 16 (P < 0·05). Iron pyrophosphate-fortified fruit juice improves Fe status and may be used to prevent Fe-deficiency anaemia.

The role of zinc protoporphyrin measurement in the differentiation between primary myelofibrosis and essential thrombocythaemia

The differentiation between primary myelofibrosis (PMF) and essential thrombocythaemia (ET) may be difficult especially in early-stage disease. In PMF, increased levels of inflammatory cytokines induce impaired iron utilisation and disturbed erythropoiesis. In conditions with impaired iron support to erythropoiesis, zinc protoporphyrin (ZPP) is produced instead of heme. Here, we investigate whether ZPP concentration can be useful in the differentiation between PMF and ET. Seventy newly diagnosed patients (PMF, n=24; ET, n=46) were analysed. Intraerythrocytic ZPP concentration (normal≤40 μmol/mol heme) was measured by an Aviv front-face haematofluorometer. In PMF, ZPP concentrations were significantly increased when compared to ET (99±37 μmol/mol heme vs. 36±13 μmol/mol heme, p<0.0001). There was also a significant difference between early-stage PMF and advanced disease (77±30 μmol/mol heme vs. 122±31 μmol/mol heme, p=0.003). ZPP>76 μmol/mol heme as observed in 71% of PMF patients were not seen in ET. In PMF patients responding to immunosuppressive treatment (n=4), the increase in haemoglobin was accompanied by declining ZPP. In summary, by detecting the disturbed iron metabolism common in PMF, ZPP may assist in the differentiation between PMF and ET. Concentrations>60 μmol/mol heme are unlikely in ET if iron deficiency is excluded. ZPP determination is also useful for monitoring the effect of therapy in PMF.

Commentary: Iron deficiency and hair loss: problems with measurement of iron

Iron is involved in many critical physiologic processes within the hair follicle, suggesting that iron deficiency could disrupt hair synthesis. However, studies of iron as a cause of hair loss have produced conflicting results. Some of the discrepancies may relate to limitations of assays for iron deficiency. This commentary discusses the sensitivity and specificity of available tests for iron deficiency and presents practical guidelines for testing and supplementation.

Iron status during anti-TNF therapy in children with juvenile idiopathic arthritis

Patients with active juvenile idiopathic arthritis (JIA) have frequently low haemoglobin (Hgb) due to inflammation and/or iron deficiency. The aim of the study was to evaluate the effect of anti-tumor necrosis factor (TNF) therapy on their iron status. Twenty children with JIA were treated with either etanercept (n = 8) or infliximab (n = 12) for 12 months. Iron status was assessed during anti-TNF treatment by Hgb, mean corpuscular volume of red blood cells (MCV), serum iron (sFe), ferritin, percent transferrin saturation (sTrfesat) and serum transferrin receptor concentration (sTfR). The sTfR/log ferritin index (TfR/logF) was also used. Prior to the therapy, Hgb and MCV were 118 ± 15.5 g/L and 79 ± 7.7 fl in the infliximab group, and 113 ± 12.5 g/L and 78 ± 5.8 fl in the etanercept group, respectively. In the whole group of patients, sFe was 6.3 ± 4.1 μmol/L and sTrfesat was 9% ± 6%. During anti-TNF therapy, Hgb and MCV improved significantly without use of iron supplementation, and sFe and sTrfesat increased from low to normal levels while inflammation markers decreased, except in one patient, in whom sTfR stayed elevated and the TfR/logF index value was high. In patients with active JIA associated with anaemia, low levels of sFe and sTrfesat cannot be used as markers for iron deficiency. In such patients, sTfR together with TfR/logF seem to be useful in assessing iron deficiency.

Metalloproteins and metal sensing

Almost half of all enzymes must associate with a particular metal to function. An ambition is to understand why each metal-protein partnership arose and how it is maintained. Metal availability provides part of the explanation, and has changed over geological time and varies between habitats but is held within vital limits in cells. Such homeostasis needs metal sensors, and there is an ongoing search to discover the metal-sensing mechanisms. For metalloproteins to acquire the right metals, metal sensors must correctly distinguish between the inorganic elements.

Evaluation of iron deficiency as a nutritional adaptation to infectious disease: an evolutionary medicine perspective

An evolutionary perspective suggests that iron deficiency may have opposing effects on infectious disease risk, decreasing susceptibility by restricting iron availability to pathogens, and increasing susceptibility by compromising cellular immunocompetence. In some environments, the trade-off between these effects may result in optimal iron intake that is inadequate to fully meet body iron needs. Thus, it has been suggested that moderate iron deficiency may protect against acute infection, and may represent a nutritional adaptation to endemic infectious disease stress. To test this assertion, we examined the association between infection, reflected by C-reactive protein, a biomarker of inflammation, and iron status, reflected by transferrin receptor (TfR) and zinc protoporphyrin to heme ratio (ZPP:H), among school-age Kenyan children, and evaluated the hypothesis that moderate iron deficiency is associated with lower odds of infectious disease. TfR > 5.0 mg/l, with sensitivity and specificity for iron deficiency (ZPP:H > 80 micromol/mol) of 0.807 and 0.815, was selected as the TfR definition of iron deficiency. Controlling for age and triceps skinfold thickness (TSF), the odds ratio (OR) for acute viral or bacterial infection associated with iron deficiency (compared to normal/replete) was 0.50 (P = 0.11). Controlling for age and TSF, the OR for infection associated with an unequivocally iron replete state (compared to all others) was 2.9 (P = 0.01). We conclude that iron deficiency may protect against acute infection in children.

Iron deficiency anemia: diagnosis and management

PURPOSE OF REVIEW

Iron deficiency anemia (IDA) still remains universally problematic worldwide. The primary focus of this review is to critique articles published over the past 18 months that describe strategies for the diagnosis and management of this prevalent condition.

RECENT FINDINGS

The medical community continues to lack consensus when identifying the optimal approach for the diagnosis and management of IDA. Current diagnostic recommendations revolve around the validity and practicality of current biomarkers such as soluble transferrin-receptor concentrations and others, and cause-based diagnostics that potentially include endoscopy. Management of IDA is based on supplementation combined with effective etiological treatment. Advances in oral and parenteral low-molecular-weight iron preparations has expanded and improved treatment modalities for IDA. Since the introduction of low versus high-molecular-weight intravenous iron administration, there have been fewer serious adverse events associated with parenteral iron preparations.

SUMMARY

Best practice guidelines for diagnosing and managing IDA should include the design of an algorithm that is inclusive of multiple biomarkers and cause-based diagnostics, which will provide direction in managing IDA, and distinguish between IDA from the anemia of chronic disease.

Methods to assess iron and iodine status

Four methods are recommended for assessment of iodine nutrition: urinary iodine concentration, the goitre rate, and blood concentrations of thyroid stimulating hormone and thyroglobulin. These indicators are complementary, in that urinary iodine is a sensitive indicator of recent iodine intake (days) and thyroglobulin shows an intermediate response (weeks to months), whereas changes in the goitre rate reflect long-term iodine nutrition (months to years). Spot urinary iodine concentrations are highly variable from day-to-day and should not be used to classify iodine status of individuals. International reference criteria for thyroid volume in children have recently been published and can be used for identifying even small goitres using thyroid ultrasound. Recent development of a dried blood spot thyroglobulin assay makes sample collection practical even in remote areas. Thyroid stimulating hormone is a useful indicator of iodine nutrition in the newborn, but not in other age groups. For assessing iron status, haemoglobin measurement alone has low specificity and sensitivity. Serum ferritin remains the best indicator of iron stores in the absence of inflammation. Measures of iron-deficient erythropoiesis include transferrin iron saturation and erythrocyte zinc protoporphyrin, but these often do not distinguish anaemia due to iron deficiency from the anaemia of chronic disease. The serum transferrin receptor is useful in this setting, but the assay requires standardization. In the absence of inflammation, a sensitive method to assess iron status is to combine the use of serum ferritin as a measure of iron stores and the serum transferrin receptor as a measure of tissue iron deficiency.

The paradox of anemia with high meat intake: a review of the multifactorial etiology of anemia in the Inuit of North America

Anemia is a serious concern among indigenous populations in North America, and it appears to be widespread among the Inuit despite abundant intakes of heme iron. It is therefore hypothesized that anemia for the Inuit involves other dietary factors not usually associated with animal foods, such as low intakes of vitamin A and/or folate, riboflavin, and vitamin C. Also, Helicobacter pylori infection and/or parasitosis may result in gastrointestinal blood loss and/or functional iron deficiency. This review aims to describe factors that may cause anemia in Inuit populations despite high meat intakes, abundant bioavailable iron, and other important hematological nutrients.

Cord blood zinc protoporphyrin/heme ratio in minority neonates at risk for iron deficiency

We measured cord blood zinc protoporphyrin/heme (ZnPP/H) and plasma ferritin in healthy African-American and Hispanic newborns, matched by gestation with Caucasian newborns. In these at-risk minorities, cord ZnPP/H was higher and plasma ferritin lower, supporting the feasibility of screening newborns at-risk for iron deficiency at birth.

Reticulocyte enrichment of zinc protoporphyrin/heme discriminates impaired iron supply during early development

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 DeltaZnPP/H. In rats, although the whole or top ZnPP/H differed by postnatal age, DeltaZnPP/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 DeltaZnPP/H was greater than controls. In rats and newborn humans, DeltaZnPP/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.

Critical review of strategies to prevent and control iron deficiency in children

Iron deficiency is prevalent in infants and young children in developing countries and is associated with adverse developmental outcomes. The routine provision of additional iron by food fortification or the use of iron supplements is generally recommended. The wisdom of this approach in regions where the transmission of Plasmodium falciparum malaria is perennial and intense is now being questioned, because a large trial in Pemba, Tanzania, demonstrated an increased risk of serious morbidity among children under the age of 3 years who were given routine daily iron and folic acid supplements. However, the results of a concurrent substudy suggest that the untoward effects occurred in children who were not iron deficient, and that iron deficiency itself is associated with an increased risk of severe morbidity that can be reduced by iron and folic acid supplementation. There is an urgent need for additional research to confirm these observations, to establish the role, if any, of the concurrent folic acid supplementation, to evaluate the risk of alternative methods for delivering iron that, on theoretical grounds, could be safer, and to establish the programmatic feasibility of targeting iron fortificants or supplements to iron-deficient children. It is evident that a single strategy for ensuring adequate iron nutrition in young children in different parts of the world is no longer likely to be satisfactory. Moreover, integration with other health-related strategies, particularly malaria control programs, will be essential.

Iron and anemia in human biology: a review of mechanisms

The biology of iron in relation to anemia is best understood by a review of the iron cycle, since the majority of iron for erythropoiesis is provided by iron recovered from senescent erythrocytes. In iron-deficiency anemia, storage iron declines until iron delivery to the bone marrow is insufficient for erythropoiesis. This can be monitored with clinical indicators, beginning with low plasma ferritin, followed by decreased plasma iron and transferrin saturation, and culminating in red blood cells with low-Hb content. When adequate dietary iron is provided, these markers show return to normal, indicating a response to the dietary supplement. Anemia of inflammation (also known as anemia of chronic disease, or ACD) follows a different course, because in this form of anemia storage iron is often abundant but not available for erythropoiesis. The diagnosis of ACD is more difficult than the diagnosis of iron-deficiency anemia, and often the first identified symptom is the failure to show a response to a dietary iron supplement. Confirmation of ACD is best obtained from elevated markers of inflammation. The treatment of ACD, which typically employs erythropoietin (EPO) supplements and intravenous iron (i.v.-iron), is empirical and often falls shorts of therapeutic goals. Dialysis patients show a complex pattern of anemia, which results from inadequate EPO production by the kidney, inflammation, changes in nutrition, and blood losses during treatment. EPO and i.v.-iron are the mainstays of treatment. Patients with heart failure can be anemic, with incidence as high as 50%. The causes are multifactorial; inflammation now appears to be the primary cause of this form of anemia, with contributions from increased plasma volume, effects of drug therapy, and other complications of heart disease. Discerning the mechanisms of anemia for the heart failure patient may aid rational therapy in each case.

Reticulocyte haemoglobin content vs. soluble transferrin receptor and ferritin index in iron deficiency anaemia accompanied with inflammation

Ferritin concentration, as a parameter of iron status that is commonly used in the diagnosis of iron deficiency anaemia (IDA), often has limited values if the iron deficiency is accompanied by inflammatory disease. This study evaluated the value of reticulocyte haemoglobin content (CHr) and soluble transferrin receptor-ferritin index (sTfR/F) in the diagnosis of IDA and differential diagnosis of IDA and anaemia of chronic disease. The study included 66 nonanaemic individuals as controls, 86 patients with IDA divided into noninflammatory and inflammatory subgroups, and 32 patients with anaemia of chronic disease. Blood count, iron, transferrin saturation, total iron binding capacity, ferritin, C-reactive protein, sTfR and CHr were determined. Receiver operator characteristic curve analysis showed very high discriminating power for CHr, soluble transferrin receptor (sTfR) and sTfR/F in the diagnosis of IDA. In patients with anaemia of chronic disease these parameters showed no significant difference from the control. CHr and sTfR enabled recognition of iron deficiency and were not affected by acute phase reaction. They are sensitive markers of body iron status with additional value to conventional tests for the detection of iron deficiency.

Zinc protoporphyrin, a useful parameter to address hyperferritinemia

Zinc protoporphyrin (ZPP) is produced instead of heme as soon as iron support to erythropoiesis becomes insufficient. In iron deficiency the intra-erythrocytic ZPP concentration is increased. The aim of this study was to investigate whether ZPP is influenced by increased iron levels in hereditary hemochromatosis (HE) and is useful in the clarification of hyperferritinemia. Twenty HE patients and 160 patients with hyperferritinemic caused by anemia of chronic disorders, liver diseases, transfusional iron overload and hematologic or solid malignancies were enrolled. ZPP was measured using the Aviv front-face hematofluorometer (normal <or= 40 micromol/mol heme). In HE, ZPP was significantly lower (median, 20 micromol/mol heme; p = 0.0005) compared to our historical control group. At diagnosis, 15 (75%) HE patients had ZPP values <or=25 micromol/mol heme. After phlebotomy, ZPP remained unchanged (median, 23 micromol/mol heme), although the initially high ferritin concentration decreased to normal. ZPP values in the other hyperferritinemic groups were significantly higher compared to HE and control groups. In contrast to HE, ZPP values <or=25 micromol/mol heme were only observed in 11% of cases with non-transfusional hyperferritinemia. The diagnostic accuracy of a ZPP <or=25 micromol/mol heme to detect HE in non-transfused hyperferritinemic patients was 87%, with a sensitivity of 75% and a specificity of 89%. Showing significantly lower values in HE, ZPP seems to be a useful parameter in distinguishing HE from other hyperferritinemic disorders as those conditions are generally accompanied by an increased ZPP.

Iron status of inner-city African-American infants

The iron status of African-American infants continues to be subject to debate. We characterized the iron status of 198 9-month-old inner-city infants (94% fed iron-fortified formula) using a comprehensive panel of measures and assessing lead and inflammation markers. The proportion with iron deficiency was calculated based on three approaches (> or = 2 abnormal iron measures with or without anemia for MCV model--NHANES II, ferritin model--NHANES III, or Sweden/Honduras study) and a promising new measure-body iron, calculated from ferritin and transferrin receptor (TfR). There were no sex differences for any iron measure. Hb < 110 g/l was observed in 25%; Hb < or = 105 g/l in 10.1%. Free erythrocyte protoporphyrin (FEP) values were elevated without elevated lead concentrations or an inflammatory response: mean FEP = 86.6 microg/dl red blood cells [75.5 micromol/mol heme]; 52.3% were > 80 microg/dl (1.42 micromol/l), almost half of which were accompanied by a second abnormal iron measure. The estimated prevalence of iron deficiency was 14.4, 5.3, and 2.5% for the MCV model, ferritin model, and Sweden/Honduras cutoffs, respectively, and 4.1% for body iron < 0 mg/kg. Regulation of iron storage is immature at < 1 year of age, making estimates of iron deficiency that depend on ferritin, including body iron, suspect in this age period. Thus, the "true" prevalence of iron deficiency could not be established with confidence due to major differences in the results, depending on the guidelines used. Functional indicators of poor iron status in young infants are urgently needed.

Zinc protoporphyrin/heme in large-for-gestation newborns

BACKGROUND

Zinc protoporphyrin/heme (ZnPP/H) ratios are indicators of incomplete erythrocyte iron delivery. ZnPP/H is more sensitive than measures of iron stores, such as plasma ferritin, in identifying early pre-anemic iron-deficient erythropoiesis. Cord ZnPP/H ratios are elevated in conditions associated with fetal hypoxia, such as diabetes mellitus during pregnancy. In chronic fetal hypoxemia, erythrocyte and hemoglobin syntheses are accelerated and iron is incorporated into erythrocytes. Cord ZnPP/H ratios are correlated with fetal size after diabetic pregnancy. Because fetal size is a surrogate for diabetes control, it is unclear whether glycemic control in diabetes mellitus or fetal size was the major determinant of ZnPP/H ratios and disturbed erythrocyte iron delivery.

OBJECTIVE

Our goal was to examine whether ZnPP/H ratios were elevated or were associated with growth in large-for-gestation newborns born to mothers without the diagnosis of diabetes mellitus.

METHODS

In cord blood samples from large and appropriately grown healthy newborns, we measured ZnPP/H and indices of erythropoiesis and iron status. Analyses included simple linear regression, Fisher's exact, and unpaired t testing.

RESULTS

In the absence of diabetes mellitus, ZnPP/H in 25 large and 24 appropriately grown healthy newborns was similar, and the ratios were within the limits of previously reported normal cord ZnPP/H. Ratios were not correlated with plasma ferritin levels. In large newborns, but not appropriately grown newborns, ZnPP/H ratios were positively correlated with fetal growth (p < 0.03) and estimates of body hemoglobin (p <0.04).

CONCLUSIONS

Despite 33% greater body hemoglobin mass observed in healthy large, compared to appropriately grown newborns, mean ZnPP/H was normal. Iron incorporation into erythrocytes in large newborns appears adequate. Because the association of ZnPP/H with size and estimated body hemoglobin was observed only in large newborns, factors determining ZnPP/H may differ between large and appropriately grown newborns.

Elevated zinc protoporphyrin/heme ratios in umbilical cord blood after diabetic pregnancy

OBJECTIVE

Offspring of diabetes patients may suffer from tissue iron deficiency. Erythrocyte zinc protoporphyrin/heme (ZnPP/H) ratios measure impaired iron status. The aim of the study was to examine whether cord ZnPP/H ratios were associated with pregnancy glycemic control.

METHODS

ZnPP/H was measured in cord blood from 31 pregnancies with insulin-treated diabetes (diabetes group) and compared to population normal values. Maternal glycemic control was assessed by daily glucose log, glycosylated hemoglobin and birth weight.

RESULTS

Median cord ZnPP/H was higher in the diabetes group than the population normal values (106 (65.2 to 146.8) microM/M vs 68.2 (37.6 to 98.8) micro/M, P < 0.0001). Ratios were directly correlated to surrogates of control (glycosylated hemoglobin, P = 0.05, and birth weight, P < 0.04). Cord ZnPP/H ratios from pregnancies with pre-existing and gestational diabetes were similar.

CONCLUSION

Because cord ZnPP/H was higher in large offspring of diabetic pregnancy, it might identify greater iron utilization for fetal erythropoiesis.

Hematologic manifestations of celiac disease

Celiac disease is a common systemic disorder that can have multiple hematologic manifestations. Patients with celiac disease may present to hematologists for evaluation of various hematologic problems prior to receiving a diagnosis of celiac disease. Anemia secondary to malabsorption of iron, folic acid, and/or vitamin B12 is a common complication of celiac disease and many patients have anemia at the time of diagnosis. Celiac disease may also be associated with thrombocytosis, thrombocytopenia, leukopenia, venous thromboembolism, hyposplenism, and IgA deficiency. Patients with celiac disease are at increased risk of being diagnosed with lymphoma, especially of the T-cell type. The risk is highest for enteropathy-type T-cell lymphoma (ETL) and B-cell lymphoma of the gut, but extraintestinal lymphomas can also be seen. ETL is an aggressive disease with poor prognosis, but strict adherence to a gluten-free diet may prevent its occurrence.