Iron Nutrition of Pre-Schoolers in High-Income Countries: A Review

Pre-schoolers are vulnerable to iron deficiency, which, in high-resource countries, is mainly caused by suboptimal or poorly absorbable iron intakes. This review examines the prevalence of inadequate iron intakes and status, and the non-dietary factors associated with these, among children aged between 2 and 5 years within high-income countries. It then considers the quality of the pre-schooler diet in terms of dietary factors, dietary patterns, and iron intakes. Additionally, it discusses the assessment of iron bioavailability and examines the various methods used to estimate the amount of absorbable iron in pre-schooler diets. Knowledge of the adequacy of iron intakes and bioavailability of iron intakes, and dietary patterns associated with iron intakes can facilitate the design and implementation of effectively targeted community-based intervention studies to improve iron intakes and iron bioavailability to minimise the risk of iron deficiency.

Prevalence and Associated Factors of Iron Deficiency and Iron Deficiency Anemia Among Under-5 Children: A Systematic Review and Meta-Analysis

Background. Iron deficiency anemia is a common health problem that affects children under the age of five. Children’s cognitive performance is impaired by iron deficiency, which impacts their psychomotor development. Therefore, the aim of this study was to determine the global prevalence and associated factors of iron deficiency and iron deficiency anemia among under-5 children. Methods. Relevant publications published till March 30, 2021 were identified in databases such as Medline/PubMed, Science Direct, Popline, EMBASE, African Journals Online, Scopus, and Google Scholar. The STATA version 11 software was utilized for the analysis. To determine the level of heterogeneity, I² test statistics were used. To detect publication bias, funnel plots analysis and the Egger weighted regression test were used. Results. The global pooled prevalence of iron deficiency anemia and iron deficiency was 16.42% (95% CI: 10.82, 22.01) and 17.95% (95% CI: 13.49, 22.41), respectively. Age less than 2 years (OR = 1.26; 95% CI: 1.14, 1.38) and living in a large family size (OR = 1.38; 95% CI: 1.18, 1.58) were associated with iron deficiency anemia. Children born from anemic mother, low birth weight, and do not drink iron fortified milk (OR = 1.20; 95% CI: 1.05, 1.36), (OR = 1.15; 95% CI: 1.01, 1.36) and (OR = 1.28; 95% CI: 1.10, 1.46), respectively were associated factors of iron deficiency in under-5 children. Conclusion. The prevalence of iron deficiency anemia and iron deficiency was significant across the globe, particularly in Asia and Africa. Therefore, regular screening and treatment of iron deficiency and iron deficiency anemia are required especially in high-risk children to reduce their complication.

PROSPERO registration number: CRD42021267060

Clinical Immunoassay for Human Hepcidin Predicts Iron Deficiency in First-Time Blood Donors

BACKGROUND

Serum markers currently used as indicators of iron status have clinical limitations. Hepcidin, a key regulator of iron homeostasis, is reduced in iron deficiency (ID) and increased in iron overload. We describe the first CLIA-validated immunoassay with excellent accuracy and precision to quantify human serum hepcidin. Its diagnostic utility for detecting ID in first-time blood donors was demonstrated.

METHODS

A monoclonal competitive ELISA (C-ELISA) was developed for the quantitation of human hepcidin and validated according to CLIA guidelines. Sera from nonanemic first-time blood donors (n = 292) were analyzed for hepcidin, ferritin, transferrin, and serum iron. Logistic regression served to determine the utility of hepcidin as a predictor of ID.

RESULTS

The C-ELISA was specific for human hepcidin and had a low limit of quantitation (4.0 ng/mL). The hepcidin concentration measured with the monoclonal C-ELISA was strongly correlated with a previously established, extensively tested polyclonal C-ELISA (Blood 2008;112:4292-7) (r = 0.95, P < 0.001). The area under the receiver operating characteristic curve for hepcidin as a predictor of ID, defined by 3 ferritin concentration thresholds, was >0.9. For predicting ID defined by ferritin <15 ng/mL, hepcidin <10 ng/mL yielded sensitivity of 93.1% and specificity of 85.5%, whereas the same hepcidin cutoff for ferritin <30 ng/mL yielded sensitivity of 67.6% and specificity of 91.7%.

CONCLUSION

The clinical measurement of serum hepcidin concentrations was shown to be a potentially useful tool for diagnosing ID.

Is the prevalence of anemia in children living at high altitudes real? An observational study in Peru

Anemia diagnosis in populations residing at high altitude (HA) involves an adjustment of hemoglobin (Hb) values owing to the increase in its concentration with altitude. The suitability of the adjustment has been questioned since Hb concentrations depend on how adapted a population is to HA. In Peru, anemia in preschool children (PSC) is a matter of severe public concern for its high rates; in the city of Puno (∼3800 MASL), for example, 67.7% of children under 3 years are diagnosed with anemia. Here, we conducted an observational study in PSC living at different altitudes in Puno to assess Hb, iron status, and the suitability of altitude-adjusted Hb values in defining iron deficiency anemia. After adjusting Hb, 65.66% of the population had anemia, while only 4.8% of PSC had anemia when using unadjusted Hb. Receiver-operating characteristic curves using total body iron (TBI) as a marker of iron status are presented. In the 36- to 59-month age group, unadjusted Hb performed better than altitude-adjusted Hb. In the 6- to 35-month age group, anemia (adjusted or unadjusted) was not associated with TBI. We conclude that Hb adjustment by altitude is not appropriate. Anemia at an early age is not entirely attributable to iron deficiency.

Uncovering the mechanism of the effects of Paeoniae Radix Alba on iron-deficiency anaemia through a network pharmacology-based strategy

BACKGROUND

Paeoniae Radix Alba, the root of the plant Paeonia lactiflora Pall, is a common blood-enriching drug in traditional Chinese medicine. Its effectiveness in the clinical treatment of anaemia is remarkable, but its potential pharmacologic mechanism has not been clarified.

METHODS

In this study, the potential pharmacologic mechanism of Paeoniae Radix Alba in the treatment of iron-deficiency anaemia was preliminarily elucidated through systematic and comprehensive network pharmacology.

RESULTS

Specifically, we obtained 15 candidate active ingredients from among 146 chemical components in Paeoniae Radix Alba. The ingredients were predicted to target 77 genes associated with iron-deficiency anaemia. In-depth analyses of these targets revealed that they were mostly associated with energy metabolism, cell proliferation, and stress responses, suggesting that Paeoniae Radix Alba helps alleviate iron-deficiency anaemia by affecting these processes. In addition, we conducted a core target analysis and a cluster analysis of protein-protein interaction (PPI) networks. The results showed that four pathways, the p53 signalling pathway, the IL-17 signalling pathway, the TNF signalling pathway and the AGE-RAGE signalling pathway in diabetic complications, may be major pathways associated with the ameliorative effects of Paeoniae Radix Alba on iron-deficiency anaemia. Moreover, molecular docking verified the credibility of the network for molecular target prediction.

CONCLUSIONS

Overall, this study predicted the functional ingredients in Paeoniae Radix Alba and their targets and uncovered the mechanism of action of this drug, providing new insights for advanced research on Paeoniae Radix Alba and other traditional Chinese medicines.

Serum and Urinary Hepcidin for Diagnosing Iron-deficiency Anemia in Under-5 Children

Bone marrow iron estimation remains the gold standard for diagnosing iron-deficiency anemia (IDA); serum ferritin, total iron-binding capacity, and transferrin saturation are routinely used as surrogate markers of IDA. However, these tests are marred by problems like poor specificity and sensitivity. Recently, hepcidin, a protein hormone synthesized in the liver and excreted in urine, has been shown to be related to iron status. We estimated the serum and urinary hepcidin levels in healthy children 6 to 60 months of age with (n=30) and without IDA (n=30). The mean (SD) serum hepcidin levels in children with IDA were significantly lower than those in children without IDA (3.03 [1.06] vs. 4.78 [3.94] ng/mL; P=0.02). The mean (SD) urinary hepcidin levels were also significantly lower in children with IDA than those in children without IDA (2.29 [0.53] vs. 2.79 [0.75] ng/mL; P=0.004). Performance of urinary and serum hepcidin compared with serum ferritin (<12 µg/L) for diagnosing IDA in terms of area under the receiver operating characteristic curve was 0.704 (P=0.007) and 0.59 (P=0.22), respectively. Serum hepcidin is not useful for diagnosing IDA in under-5 children. In contrast, urinary hepcidin holds promise as a noninvasive diagnostic tool for IDA in under-5 children.

Serum Hepcidin and Soluble Transferrin Receptor in the Assessment of Iron Metabolism in Children on a Vegetarian Diet

The aim of this study was to assess the effect of vegetarian diet on iron metabolism parameters paying special attention to serum hepcidin and soluble transferrin receptor (sTfR) concentrations in 43 prepubertal children (age range 4.5-9.0 years) on vegetarian and in 46 children on omnivorous diets. There were no significant differences according to age, weight, height, and body mass index (BMI) between vegetarian and omnivorous children. Vegetarians had similar intake of iron and vitamin B12 and a significantly higher intake of vitamin C (p < 0.05) compared with non-vegetarians. Hematologic parameters and serum iron concentrations were within the reference range in both groups of children. Serum transferrin levels were similar in all subjects; however, ferritin concentrations were significantly (p < 0.01) lower in vegetarians than in omnivores. In children on a vegetarian diet, median hepcidin levels were lower (p < 0.05) but sTfR concentrations significantly higher (p < 0.001) compared with omnivorous children. In the multivariate regression model, we observed associations between hepcidin level and ferritin concentration (β = 0.241, p = 0.05) in the whole group of children as well as between hepcidin concentration and CRP level (β = 0.419, p = 0.047) in vegetarians. We did not find significant associations with concentration of sTfR and selected biochemical, anthropometric, and dietary parameters in any of the studied groups of children. As hematologic parameters and iron concentrations in vegetarians and omnivores were comparable and ferritin level was lower in vegetarians, we suggest that inclusion of novel markers, in particular sTfR (not cofounded by inflammation) and hepcidin, can better detect subclinical iron deficiency in children following vegetarian diets.

Targeting interleukin-6 in autoimmune uveitis

Interleukin-6 (IL-6) is a key cytokine that is strongly up-regulated during infection and inflammation. Featuring pleiotropic activity, IL-6 is responsible for the induction of hepatic acute-phase proteins, trafficking of acute and chronic inflammatory cells, differentiation of adaptive T cell responses, homeostatic regulation, and tissue regeneration. Dysregulated IL-6 production has been associated with the development of a wide variety of systemic immune-mediated, chronic diseases, and even certain types of cancer. From the ocular perspective, significant elevation of IL-6 has been found in ocular fluids derived from diabetic macular edema, retinal vein occlusion, and refractory/chronic uveitis patients. During the last decade, tocilizumab, a neutralizing monoclonal antibody (mAb) that targets the IL-6 receptor (IL-6R), has been approved for the treatment of rheumatoid arthritis in >100 countries worldwide. Furthermore, it has been reported to be effective for the treatment of a number of autoimmune diseases including uveitis and its associated macular edema. Currently numerous candidate molecular strategies targeting the IL-6 signaling pathways are in progress through clinical trials in various disorders. Herein we discuss the basic biology of IL-6 and its pathological role in the development of immune-mediated conditions, particularly focusing on inflammatory eye diseases. It also provides an overview of the on-going clinical trials with the new anti-IL-6 mAbs and their potential use in the clinical practice.