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Rauf A, Shariati MA, Khalil AA, Bawazeer S, Heydari M, Plygun S, Laishevtcev A, Hussain MB, Alhumaydhi FA, Aljohani ASM. Hepcidin, an overview of biochemical and clinical properties. Steroids 2020; 160:108661. [PMID: 32450084 DOI: 10.1016/j.steroids.2020.108661] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/31/2020] [Accepted: 05/17/2020] [Indexed: 12/16/2022]
Abstract
Hepcidin is a peptide hormone which helps in regulating iron homeostasis in the human body. Iron obtained from daily diet is passed through the intestinal enterocyte apical membrane via divalent metal transporter 1 (DMT1), which is either stored as ferritin or moved into the plasma by hepcidin-ferroportin (Fpn) as an exporter. Hepcidin (hepatic bactericidal protein) is a cysteine rich peptide, was initially identified as a urinary antimicrobial peptide. It contains 25 amino acids and four disulfide bridges. It has significant role in regulation of iron in the body. Stimulation of iron in plasma and further its storage is linked with the production of hepcidin. This enhancement of iron hampers the absorption of iron from the diet. The cause of hereditary recessive anemia also known as Iron-refractory iron deficiency anemia (IRIDA) is characterized by increased hepcidin production due to a gene mutation in the suppressor matriptase-2/TMPRSS6. During infection, hepcidin plays a defensive role against various infections by depleting the extracellular iron from the body. Moreover, hepcidin lowers the concentrations of iron from the duodenal enterocytes, macrophages and also decrease its transport across the placenta.This review highlights the significant role of hepcidin in the iron homeostasis and as an antimicrobial agent.
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Affiliation(s)
- Abdur Rauf
- Department of Chemistry, University of Swabi, Anbar 23561, Khyber Pakhtunkhwa, Pakistan.
| | - Mohammad Ali Shariati
- Laboratory of Biocontrol and Antimicrobial Resistance, Orel State University Named After I.S. Turgenev, 302026 Orel, Russia
| | - Anees Ahmed Khalil
- University Institute of Diet and Nutritional Sciences, Faculty of Allied Health Sciences, The University of Lahore, Pakistan
| | - Saud Bawazeer
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Umm Al-Qura University, Makkah, P.O. Box 42, Saudi Arabia
| | - Mojtaba Heydari
- Poostchi Ophthalmology Research Center, Shiraz University of Medical Sciences, Shiraz, Sciences, Shiraz, Iran
| | - Sergey Plygun
- Laboratory of Biocontrol and Antimicrobial Resistance, Orel State University Named After I.S. Turgenev, 302026 Orel, Russia; European Society of Clinical Microbiology and Infectious Diseases, Basel 4051, Switzerland; Russian Research Institute of Phytopathology, Moscow Region 143050, Russia
| | - Alexy Laishevtcev
- Laboratory of Biocontrol and Antimicrobial Resistance, Orel State University Named After I.S. Turgenev, 302026 Orel, Russia; Federal Research Center - All-Russian Scientific Research Institute of Experimental Veterinary Medicine named after K.I. Skryabin and Y.R. Kovalenko of the Russian Academy of Sciences, Moscow 109428, Russia
| | - Muhammad Bilal Hussain
- Institute of Home and Food Sciences, Government College University, Faisalabad, Pakistan
| | - Fahad A Alhumaydhi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah, Saudi Arabia
| | - Abdullah S M Aljohani
- Department of Veterinary Medicine, College of Agriculture and Veterinary Medicine, Qassim University, Buraydah, Saudi Arabia
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Kannan D, Yadav N, Ahmad S, Namdev P, Bhattacharjee S, Lochab B, Singh S. Pre-clinical study of iron oxide nanoparticles fortified artesunate for efficient targeting of malarial parasite. EBioMedicine 2019; 45:261-277. [PMID: 31255656 PMCID: PMC6642363 DOI: 10.1016/j.ebiom.2019.06.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 06/01/2019] [Accepted: 06/13/2019] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Artesunate the most potent antimalarial is widely used for the treatment of multidrug-resistant malaria. The antimalarial cytotoxicity of artesunate has been mainly attributed to its selective, irreversible and iron- radical-mediated damage of parasite biomolecules. In the present research, iron oxide nanoparticle fortified artesunate was tested in P. falciparum and in an experimental malaria mouse model for enhancement in the selectivity and toxicity of artesunate towards parasite. Artesunate was fortified with nontoxic biocompatible surface modified iron oxide nanoparticle which is specially designed and synthesized for the sustained pH-dependent release of Fe2+ within the parasitic food vacuole for enhanced ROS spurt. METHODS Antimalarial efficacy of Iron oxide nanoparticle fortified artesunate was evaluated in wild type and artemisinin-resistant Plasmodium falciparum (R539T) grown in O + ve human blood and in Plasmodium berghei ANKA infected swiss albino mice. Internalization of nanoparticles, the pH-dependent release of Fe2+, production of reactive oxygen species and parasite biomolecule damage by iron oxide nanoparticle fortified artesunate was studied using various biochemical, biophysical, ultra-structural and fluorescence microscopy. For determining the efficacy of ATA-IONP+ART on resistant parasite ring survival assay was performed. RESULTS The nanoparticle fortified artesunate was highly efficient in the 1/8th concentration of artesunate IC50 and led to retarded growth of P. falciparum with significant damage to macromolecules mediated via enhanced ROS production. Similarly, preclinical In vivo studies also signified a radical reduction in parasitemia with ~8-10-fold reduced dosage of artesunate when fortified with iron oxide nanoparticles. Importantly, the ATA-IONP combination was efficacious against artemisinin-resistant parasites. INTERPRETATION Surface coated iron-oxide nanoparticle fortified artesunate can be developed into a potent therapeutic agent towards multidrug-resistant and artemisinin-resistant malaria in humans. FUND: This study is supported by the Centre for Study of Complex Malaria in India funded by the National Institute of Health, USA.
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Affiliation(s)
- Deepika Kannan
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, India
| | - Nisha Yadav
- Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, India
| | - Shakeel Ahmad
- Special Center for Molecular Medicine, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, India
| | - Pragya Namdev
- Special Center for Molecular Medicine, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, India
| | - Souvik Bhattacharjee
- Special Center for Molecular Medicine, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, India
| | - Bimlesh Lochab
- Department of Chemistry, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, India.
| | - Shailja Singh
- Special Center for Molecular Medicine, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, India.
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Abstract
BACKGROUND Iron-deficiency anaemia is common during childhood. Iron administration has been claimed to increase the risk of malaria. OBJECTIVES To evaluate the effects and safety of iron supplementation, with or without folic acid, in children living in areas with hyperendemic or holoendemic malaria transmission. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library, MEDLINE (up to August 2015) and LILACS (up to February 2015). We also checked the metaRegister of Controlled Trials (mRCT) and World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) up to February 2015. We contacted the primary investigators of all included trials, ongoing trials, and those awaiting assessment to ask for unpublished data and further trials. We scanned references of included trials, pertinent reviews, and previous meta-analyses for additional references. SELECTION CRITERIA We included individually randomized controlled trials (RCTs) and cluster RCTs conducted in hyperendemic and holoendemic malaria regions or that reported on any malaria-related outcomes that included children younger than 18 years of age. We included trials that compared orally administered iron, iron with folic acid, and iron with antimalarial treatment versus placebo or no treatment. We included trials of iron supplementation or fortification interventions if they provided at least 80% of the Recommended Dietary Allowance (RDA) for prevention of anaemia by age. Antihelminthics could be administered to either group, and micronutrients had to be administered equally to both groups. DATA COLLECTION AND ANALYSIS The primary outcomes were clinical malaria, severe malaria, and death from any cause. We assessed the risk of bias in included trials with domain-based evaluation and assessed the quality of the evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. We performed a fixed-effect meta-analysis for all outcomes and random-effects meta-analysis for hematological outcomes, and adjusted analyses for cluster RCTs. We based the subgroup analyses for anaemia at baseline, age, and malaria prevention or management services on trial-level data. MAIN RESULTS Thirty-five trials (31,955 children) met the inclusion criteria. Overall, iron does not cause an excess of clinical malaria (risk ratio (RR) 0.93, 95% confidence intervals (CI) 0.87 to 1.00; 14 trials, 7168 children, high quality evidence). Iron probably does not cause an excess of clinical malaria in both populations where anaemia is common and those in which anaemia is uncommon. In areas where there are prevention and management services for malaria, iron (with or without folic acid) may reduce clinical malaria (RR 0.91, 95% CI 0.84 to 0.97; seven trials, 5586 participants, low quality evidence), while in areas where such services are unavailable, iron (with or without folic acid) may increase the incidence of malaria, although the lower CIs indicate no difference (RR 1.16, 95% CI 1.02 to 1.31; nine trials, 19,086 participants, low quality evidence). Iron supplementation does not cause an excess of severe malaria (RR 0.90, 95% CI 0.81 to 0.98; 6 trials, 3421 children, high quality evidence). We did not observe any differences for deaths (control event rate 1%, low quality evidence). Iron and antimalarial treatment reduced clinical malaria (RR 0.54, 95% CI 0.43 to 0.67; three trials, 728 children, high quality evidence). Overall, iron resulted in fewer anaemic children at follow up, and the end average change in haemoglobin from base line was higher with iron. AUTHORS' CONCLUSIONS Iron treatment does not increase the risk of clinical malaria when regular malaria prevention or management services are provided. Where resources are limited, iron can be administered without screening for anaemia or for iron deficiency, as long as malaria prevention or management services are provided efficiently.
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Affiliation(s)
- Ami Neuberger
- Rambam Health Care Campus and The Ruth and Bruce Rappaport Faculty of Medicine, Technion – Israel Institute of TechnologyDivision of Infectious DiseasesTel AvivIsrael
| | - Joseph Okebe
- Medical Research Council UnitP.O. Box 273BanjulGambia
| | - Dafna Yahav
- Beilinson Hospital, Rabin Medical CenterDepartment of Medicine E39 Jabotinski StreetPetah TikvaIsrael49100
| | - Mical Paul
- Rambam Health Care CampusDivision of Infectious DiseasesHa‐aliya 8 StHaifaIsrael33705
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Ferrer P, Castillo-Neyra R, Roy CN, Sullivan DJ Jr. Dynamic control of hepatic Plasmodium numbers by hepcidin despite elevated liver iron during iron supplementation. Microbes Infect 2016; 18:48-56. [PMID: 26384816 DOI: 10.1016/j.micinf.2015.08.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/31/2015] [Accepted: 08/31/2015] [Indexed: 12/21/2022]
Abstract
Treatment of iron deficiency anemia in malaria endemic areas is complicated as iron supplementation increases malaria risk while malaria decreases iron absorption. Here we measured the influence of hepcidin expression and non-heme iron during iron supplementation on hepatic Plasmodium berghei numbers in anemic and non-anemic mice. Despite elevated hepatic non-heme iron on the high iron diet, elevated hepcidin expression is associated with less parasite bioavailable iron and lower hepatic parasite loads in anemic, iron deficient mice after both two and six weeks of supplementation. A marginal trend to lower parasite hepatic numbers was seen in non-anemic, iron replete mice. In a transgenic model of severe anemia, mice with a deletion in Sec15l1, which reportedly have normal liver iron and normal hepcidin expression, there were no changes in liver parasite numbers or blood stage numbers or outcome in the lethal Plasmodium yoelii model. In summary during iron supplementation the lower hepatic malaria numbers are regulated more by hepcidin than the absolute level of non-heme hepatic iron.
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Abstract
Hepcidin is the master regulator of iron homeostasis in vertebrates. The synthesis of hepcidin is induced by systemic iron levels and by inflammatory stimuli. While the role of hepcidin in iron regulation is well established, its contribution to host defense is emerging as complex and multifaceted. In this review, we summarize the literature on the role of hepcidin as a mediator of antimicrobial immunity. Hepcidin induction during infection causes depletion of extracellular iron, which is thought to be a general defense mechanism against many infections by withholding iron from invading pathogens. Conversely, by promoting iron sequestration in macrophages, hepcidin may be detrimental to cellular defense against certain intracellular infections, although critical in vivo studies are needed to confirm this concept. It is not yet clear whether hepcidin exerts any iron-independent effects on host defenses.
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Affiliation(s)
- Kathryn Michels
- Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California, United States of America
| | - Tomas Ganz
- Department of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California, United States of America
- Department of Pathology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California, United States of America
| | - Borna Mehrad
- Departments of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States of America
- The Carter Center for Immunology, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Internal Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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Menon MP, Yoon SS. Prevalence and Factors Associated with Anemia Among Children Under 5 Years of Age--Uganda, 2009. Am J Trop Med Hyg 2015; 93:521-6. [PMID: 26055748 DOI: 10.4269/ajtmh.15-0102] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 05/05/2015] [Indexed: 01/08/2023] Open
Abstract
Anemia in children under 5 years of age, defined by the World Health Organization as a hemoglobin concentration < 11 g/dL, is a global public health problem. According to the 2006 Demographic Health Survey, the prevalence of anemia among children under five in Uganda was 72% in 2006. The 2009 Uganda Malaria Indicator Survey was conducted in late 2009 and revealed that over 60% of children less than 5 years of age were anemic and that over half of children tested positive for malaria via a rapid diagnostic test. Children with concomitant malaria infection, and in households without any type of mosquito net were more likely to be anemic, confirming that children under 5 years, are vulnerable to both the threat of malaria and anemia and the beneficial effect of malaria prevention tools. However, prevention and treatment of other factors associated with the etiology of anemia (e.g., iron deficiency) are likely necessary to combat the toll of anemia in Uganda.
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Affiliation(s)
- Manoj P Menon
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia; University of Washington, Seattle, Washington
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Abstract
Iron deficiency is not just anemia; it can be responsible for a long list of other manifestations. This topic is of great importance, especially in infancy and early childhood, for a variety of reasons. Firstly, iron need is maximum in this period. Secondly, diet in infancy is usually deficient in iron. Thirdly and most importantly, iron deficiency at this age can result in neurodevelopmental and cognitive deficits, which may not be reversible. Hypochromia and microcytosis in a complete blood count (CBC) makes iron deficiency anemia (IDA) most likely diagnosis. Absence of response to iron should make us look for other differential diagnosis like β thalassemia trait and anemia of chronic disease. Celiac disease is the most important cause of true IDA not responding to oral iron therapy. While oral ferrous sulphate is the cheapest and most effective therapy for IDA, simple nonpharmacological and pharmacological measures can go a long way in prevention of iron deficiency.
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Abstract
BACKGROUND AND OBJECTIVES Iron deficiency (ID) is the most common cause of anemia worldwide. The prevalence is highest among preschool-aged children. Iron is widely administered to children with or at risk for ID, but evidence of benefit among 2- to 5-year-old children has not been evaluated by systematic review. We summarize the evidence for the benefit and safety of daily iron supplementation with regard to hematologic, growth, and cognitive parameters in 2 to 5 year olds. METHODS Electronic databases, regional databases, thesis repositories, gray literature, and references of studies and previous reviews were searched. We included randomized controlled trials that compared daily oral iron supplementation with control in 2 to 5 year olds. A random-effects meta-analysis was used to synthesize predefined outcomes reported by at least 2 studies. RESULTS Of 9169 references, 15 studies met the inclusion criteria, none of which were at low risk of bias. Children receiving iron supplementation had a mean end point hemoglobin of 6.97 g/L (P < .00001; I(2) = 82%) greater than controls, whereas mean end point ferritin was 11.64 µg/L (P < .0001; I(2) = 48%) greater. No trials reported the effects of iron supplementation on ID or iron deficiency anemia, and only one reported on anemia. Limited evidence suggested that iron supplementation produced a small improvement in cognitive development but had no effect on physical growth. CONCLUSIONS In 2 to 5 year olds, daily iron supplementation increases hemoglobin and ferritin. There is a concerning lack of data on the effect of iron supplementation on clinically important outcomes including anemia, ID anemia, ID, and cognitive development. Additional interventional studies in this age group are needed.
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Affiliation(s)
- Jane Thompson
- School of Medicine, Faculty of Health Sciences, University of Adelaide, South Australia, Australia
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Jonker FAM, Calis JCJ, van Hensbroek MB, Phiri K, Geskus RB, Brabin BJ, Leenstra T. Iron status predicts malaria risk in Malawian preschool children. PLoS One 2012; 7:e42670. [PMID: 22916146 PMCID: PMC3420896 DOI: 10.1371/journal.pone.0042670] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 07/10/2012] [Indexed: 11/30/2022] Open
Abstract
Introduction Iron deficiency is highly prevalent in pre-school children in developing countries and an important health problem in sub-Saharan Africa. A debate exists on the possible protective effect of iron deficiency against malaria and other infections; yet consensus is lacking due to limited data. Recent studies have focused on the risks of iron supplementation but the effect of an individual's iron status on malaria risk remains unclear. Studies of iron status in areas with a high burden of infections often are exposed to bias. The aim of this study was to assess the predictive value of baseline iron status for malaria risk explicitly taking potential biases into account. Methods and materials We prospectively assessed the relationship between baseline iron deficiency (serum ferritin <30 µg/L) and malaria risk in a cohort of 727 Malawian preschool children during a year of follow-up. Data were analyzed using marginal structural Cox regression models and confounders were selected using causal graph theory. Sensitivity of results to bias resulting from misclassification of iron status by concurrent inflammation and to bias from unmeasured confounding were assessed using modern causal inference methods. Results and Conclusions The overall incidence of malaria parasitemia and clinical malaria was 1.9 (95% CI 1.8–2.0) and 0.7 (95% CI 0.6–0.8) events per person-year, respectively. Children with iron deficiency at baseline had a lower incidence of malaria parasitemia and clinical malaria during a year of follow-up; adjusted hazard ratio's 0.55 (95%-CI:0.41–0.74) and 0.49 (95%-CI:0.33–0.73), respectively. Our results suggest that iron deficiency protects against malaria parasitemia and clinical malaria in young children. Therefore the clinical importance of treating iron deficiency in a pre-school child should be weighed carefully against potential harms. In malaria endemic areas treatment of iron deficiency in children requires sustained prevention of malaria.
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Affiliation(s)
- Femkje A M Jonker
- Global Child Health Group, Emma Children's Hospital, Academic Medical Centre, Amsterdam, The Netherlands.
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Gwamaka M, Kurtis JD, Sorensen BE, Holte S, Morrison R, Mutabingwa TK, Fried M, Duffy PE. Iron deficiency protects against severe Plasmodium falciparum malaria and death in young children. Clin Infect Dis 2012; 54:1137-44. [PMID: 22354919 DOI: 10.1093/cid/cis010] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Iron supplementation may increase malaria morbidity and mortality, but the effect of naturally occurring variation in iron status on malaria risk is not well studied. METHODS A total of 785 Tanzanian children living in an area of intense malaria transmission were enrolled at birth, and intensively monitored for parasitemia and illness including malaria for up to 3 years, with an average of 47 blood smears. We assayed plasma samples collected at routine healthy-child visits, and evaluated the impact of iron deficiency (ID) on future malaria outcomes and mortality. RESULTS ID at routine, well-child visits significantly decreased the odds of subsequent parasitemia (23% decrease, P < .001) and subsequent severe malaria (38% decrease, P = .04). ID was also associated with 60% lower all-cause mortality (P = .04) and 66% lower malaria-associated mortality (P = .11). When sick visits as well as routine healthy-child visits are included in analyses (average of 3 iron status assays/child), ID reduced the prevalence of parasitemia (6.6-fold), hyperparasitemia (24.0-fold), and severe malaria (4.0-fold) at the time of sample collection (all P < .001). CONCLUSIONS Malaria risk is influenced by physiologic iron status, and therefore iron supplementation may have adverse effects even among children with ID. Future interventional studies should assess whether treatment for ID coupled with effective malaria control can mitigate the risks of iron supplementation for children in areas of malaria transmission.
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Affiliation(s)
- Moses Gwamaka
- Mother-Offspring Malaria Studies Project, Seattle Biomedical Research Institute, Washington, USA
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11
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Abstract
BACKGROUND Iron-deficiency anaemia is common during childhood. Iron supplementation has been claimed to increase the risk of malaria. OBJECTIVES To assess the effect of iron on malaria and deaths. SEARCH STRATEGY We searched The Cochrane Library, PUBMED, MEDLINE, LILACS; and trial registry databases, all up to June 2011. We scanned references of included trials. SELECTION CRITERIA Individually and cluster randomized controlled trials conducted in hypoendemic to holoendemic malaria regions and including children below 18 years of age. We included trials comparing orally administered iron, iron with antimalarial treatment, or iron with folic acid versus placebo or no treatment. Iron fortification was excluded. Antihelminthics could be administered to either group. Additional micronutrients had to be administered equally to both groups. DATA COLLECTION AND ANALYSIS The primary outcomes were clinical (symptomatic) malaria, severe malaria, and death. Two authors independently selected the studies and extracted the data. We assessed heterogeneity and conducted subgroup analyses by the presence of anaemia at baseline, age, and malaria endemicity. We assessed risk of bias using domain-based evaluation. We performed a fixed-effect meta-analysis for all outcomes and random-effects meta-analysis for hematological outcomes. We adjusted analyses for cluster randomized trials. MAIN RESULTS Seventy-one trials (45,353 children) were included. For clinical malaria, no significant difference between iron alone and placebo was detected, (risk ratio (RR) 0.99, 95% confidence intervals (CI) 0.90 to 1.09, 13 trials). The results were similar in the subgroups of non-anaemic children and children below 2 years of age. There was no significant difference in deaths in hyper- and holoendemic areas, risk difference +1.93 per 1000 children (95% CI -1.78 to 5.64, 13 trials, 17,898 children). Iron administered for treatment of anaemia resulted in a larger increase in haemoglobin than iron given for prevention, and the benefit was similar in hyper- or holoendemic and lower endemicity settings. Iron and folic acid supplementation resulted in mixed results for severe malaria. Overall, the risk for clinical malaria was higher with iron or with iron plus folic acid in trials where services did not provide for malaria surveillance and treatment. Iron with antimalarial treatment significantly reduced malaria. Iron supplementation during an acute attack of malaria did not increase the risk for parasitological failure, (RR 0.96, 95% CI 0.74 to 1.24, three trials) or deaths. AUTHORS' CONCLUSIONS Iron alone or with antimalaria treatment does not increase the risk of clinical malaria or death when regular malaria surveillance and treatment services are provided. There is no need to screen for anaemia prior to iron supplementation.
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Affiliation(s)
- Joseph U Okebe
- Medical Research Council Unit, P.O. Box 273, Banjul, Gambia
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Abstract
Maria Merritt and colleagues report on a Field Training Guide for Human Subjects Research Ethics that they have developed to help train field workers in ethics for research.
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Affiliation(s)
- Maria W Merritt
- Department of International Health, Johns Hopkins Berman Institute of Bioethics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, United States of America.
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Ojukwu JU, Okebe JU, Yahav D, Paul M. Cochrane review: Oral iron supplementation for preventing or treating anaemia among children in malaria-endemic areas. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/ebch.542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Kung'u JK, Wright VJ, Haji HJ, Ramsan M, Goodman D, Tielsch JM, Bickle QD, Raynes JG, Stoltzfus RJ. Adjusting for the acute phase response is essential to interpret iron status indicators among young Zanzibari children prone to chronic malaria and helminth infections. J Nutr 2009; 139:2124-31. [PMID: 19741202 DOI: 10.3945/jn.108.104026] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The extent to which the acute phase response (APR) influences iron status indicators in chronic infections is not well documented. We investigated this relationship using reported recent fever and 2 acute phase proteins (APP), C-reactive protein (CRP), and alpha-1-acid glycoprotein (AGP). In a sample of 690 children matched on age and helminth infection status at baseline, we measured plasma for AGP, CRP, ferritin, transferrin receptor (TfR), and erythropoietin (EPO) and whole blood for hemoglobin (Hb) concentration, zinc protoporphyrin (ZPP), and malaria parasite density, and we obtained maternal reports of recent fever. We then examined the influence of the APR on each iron status indicator using regression analysis with Hb as the outcome variable. Ferritin was inversely related to Hb in the APR-unadjusted model. Adjusting for the APR using reported recent fever alone was not sufficient to reverse the inverse Hb-ferritin relationship. However, using CRP and/or AGP resulted in the expected positive relationship. The best fit model included reported recent fever, AGP and CRP (R(2) = 0.241; P < 0.001). The best fit Hb-ZPP, Hb-TfR, and Hb-EPO models included reported recent fever and AGP but not CRP (R(2) = 0.253, 0.310, and 0.292, respectively; P < 0.001). ZPP, TfR, and EPO were minimally influenced by the APR, whereas ferritin was immensely affected. Reported recent fever alone cannot be used as a marker for the APR. Either AGP or CRP is useful for adjusting if only 1 APP can be measured. However, AGP best predicted the APR in this population.
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Abstract
BACKGROUND Iron-deficiency anaemia is common during childhood. Iron supplementation has been claimed to increase the risk of malaria. OBJECTIVES To assess the effect of iron on malaria and deaths. SEARCH STRATEGY We searched The Cochrane Library (2009, issue 1); MEDLINE; EMBASE; LILACS and metaRegister of Controlled Trials, all up to March 2009. We scanned references of included trials. SELECTION CRITERIA Individually and cluster-randomized controlled trials conducted in hypoendemic to holoendemic malaria regions and including children < 18 years. We included trials comparing orally administered iron with or without folic acid vs. placebo or no treatment. Iron fortification was excluded. Antimalarials and/or antiparasitics could be administered to either group. Additional micronutrients could only be administered equally to both groups. DATA COLLECTION AND ANALYSIS The primary outcomes were malaria-related events and deaths. Secondary outcomes included haemoglobin, anaemia, other infections, growth, hospitalizations, and clinic visits. We assessed risk of bias using domain-based evaluation. Two authors independently selected studies and extracted data. We contacted authors for missing data. We assessed heterogeneity. We performed fixed-effect meta-analysis and presented random-effects results when heterogeneity was present. We present pooled risk ratios (RR) with 95% confidence intervals (CIs). We used adjusted analyses for cluster-randomized trials. MAIN RESULTS Sixty-eight trials (42,981 children) fulfilled the inclusion criteria. Iron supplementation did not increase the risk of clinical malaria (RR 1.00, 95% CI 0.88 to 1.13; 22,724 children, 14 trials, random-effects model). The risk was similar among children who were non-anaemic at baseline (RR 0.96, 95% CI 0.85 to 1.09). An increased risk of malaria with iron was observed in trials that did not provide malaria surveillance and treatment. The risk of malaria parasitaemia was higher with iron (RR 1.13, 95% CI 1.01 to 1.26), but there was no difference in adequately concealed trials. Iron + antimalarial was protective for malaria (four trials). Iron did not increase the risk of parasitological failure when given during malaria (three trials). There was no increased risk of death across all trials comparing iron versus placebo (RR 1.11, 95% CI 0.91 to 1.36; 21,272 children, 12 trials). Iron supplementation increased haemoglobin, with significant heterogeneity, and malaria endemicity did not affect this effect. Growth and other infections were mostly not affected by iron supplementation. AUTHORS' CONCLUSIONS Iron does not increase the risk of clinical malaria or death, when regular malaria surveillance and treatment services are provided. There is no need to screen for anaemia prior to iron supplementation.
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Affiliation(s)
- Juliana U Ojukwu
- Department of Paediatrics, Ebonyi State University, PMB 077, Abakaliki, Ebonyi State, Nigeria
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16
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Olney DK, Kariger PK, Stoltzfus RJ, Khalfan SS, Ali NS, Tielsch JM, Sazawal S, Black R, Allen LH, Pollitt E. Development of nutritionally at-risk young children is predicted by malaria, anemia, and stunting in Pemba, Zanzibar. J Nutr 2009; 139:763-72. [PMID: 19225131 DOI: 10.3945/jn.107.086231] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Nutritionally at-risk children suffer delays in physical growth and motor and language development. Infectious diseases such as malaria pose an additional risk. We examined the cross-sectional relationships among malaria infection, hemoglobin (Hb) concentration, length-for-age Z-scores (LAZ), motor activity, behavior, and motor and language development in 841 Zanzibari children 5-19 mo old. We used structural equation modeling to test the fit of the data to a theoretical model and to examine the relationships among the variables in 3 age groups (5-9, 10-14, and 15-19 mo). The model fit the data for all age groups. In the youngest and oldest groups, children with higher malaria parasite densities had significantly lower Hb and LAZ. Higher LAZ significantly predicted higher total motor activity, and motor and language development scores in all age groups. In the oldest group, children who had higher Hb had higher motor development and activity scores. Malaria was directly and indirectly related to motor activity in the 10- to 14-mo-old group [standardized total effects, -0.14; direct, -0.10 (P = 0.015); and indirect, -0.038]. The significant fit of the models to the data and the statistical significance of many of the specific pathways highlight the complexities of the relationships between health and nutrition and child development outcomes in this population. In addition, the results suggest that multiple interventions are likely necessary to improve child development outcomes in this population of nutritionally at-risk children and that the potential effectiveness of interventions may differ according to age (i.e. prevention and treatment of anemia, stunting, and malaria).
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Affiliation(s)
- Deanna K Olney
- Program in International and Community Nutrition, University of California, Davis, CA 95616, USA.
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17
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Bowater RJ, Abdelmalik SME, Lilford RJ. The methodological quality of cluster randomised controlled trials for managing tropical parasitic disease: a review of trials published from 1998 to 2007. Trans R Soc Trop Med Hyg 2009; 103:429-36. [PMID: 19232658 DOI: 10.1016/j.trstmh.2009.01.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 08/12/2008] [Accepted: 12/17/2008] [Indexed: 11/26/2022] Open
Abstract
The aim of this review was to assess the methodological quality of cluster randomised controlled trials (CRCT) for the management of tropical parasitic disease published between 1998 and 2007. A literature survey was conducted using Medline for CRCTs of interventions aimed at managing any one of the six major tropical parasitic diseases: malaria, leishmaniasis, lymphatic filariasis, onchocerciasis, schistosomiasis and trypanosomiasis (Chagas disease). Information was extracted from the published articles in order that, for each trial, categorical responses could be made to a pre-specified list of 12 questions concerning issues relating to the methodological quality of the trial, including choice of design, generalisability, baseline assessment, blinding, use or non-use of a matched design, and accounting for the intraclass correlation in both design and analysis. The literature survey found 38 CRCTs. Of the 35 CRCTs that reported at least one human outcome, 27 were for interventions in the management of malaria whilst the rest were for managing leishmaniasis (4 trials), lymphatic filariasis (2 trials) and schistosomiasis (2 trials). For every one of the pre-specified questions that concerned an issue associated with methodological quality, the responses were consistent with the practice of trialists in relation to the given issue being generally poor.
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Affiliation(s)
- Russell J Bowater
- Department of Public Health & Epidemiology, School of Medicine, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK.
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18
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Hotez PJ, Molyneux DH. Tropical anemia: one of Africa's great killers and a rationale for linking malaria and neglected tropical disease control to achieve a common goal. PLoS Negl Trop Dis 2008; 2:e270. [PMID: 18665256 PMCID: PMC2474697 DOI: 10.1371/journal.pntd.0000270] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Peter J. Hotez
- Department of Microbiology, Immunology, & Tropical Medicine, The George Washington University and Sabin Vaccine Institute, Washington, D. C., United States of America
- * E-mail: or (PJH); (DHM)
| | - David H. Molyneux
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- * E-mail: or (PJH); (DHM)
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19
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Abstract
Recent evidence from a large, randomized, controlled trial has suggested that the universal administration of iron to children in malaria-endemic areas is associated with an increase in adverse health outcomes. The purpose of this paper is to summarize the available ecologic and intervention trials related to iron and malaria in children, and to set these against current knowledge of the biology of host-pathogen interactions involving iron metabolism. We conclude that, although not fully consistent, the balance of evidence confirms that administration of iron (usually in combination with folic acid) increases the incidence of malaria when given without prophylaxis and in the absence of universal access to treatment. The mechanisms by which additional iron can benefit the parasite are far from clear. There is evidence to suggest that the apparent detrimental effect of iron supplementation may vary according to levels of antecedent iron status, the presence of hemoglobinopathies and glucose-6-phosphate dehydrogenase (G6PD) deficiency, and other host genetic variants, such as variants in haptoglobin. The effects of malaria on host iron metabolism are also reviewed and reveal that the key cause of malaria-induced anemia is a maldistribution of iron and suppression of erythropoiesis rather than an exacerbation of gross iron deficiency. We tentatively conclude that, if it is to be recommended, universal iron supplementation in malarious areas should only be considered in conjunction with some form of prophylaxis (e.g., intermittent preventive therapy [IPT]) or in the context of good health services with ready access to facilities for malaria diagnosis and treatment. An alternative approach would be to screen for anemia and target supplementation only to anemic children. With regard to treatment, there is good evidence that iron supplementation should be withheld until the treatment schedule is complete, both because iron may inhibit treatment and because the absorption of oral iron is blocked by the inflammatory response.
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Affiliation(s)
- Andrew M Prentice
- MRC International Nutrition Group, London School of Hygiene and Tropical Medicine, London 1IE 7HT, United Kingdom.
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20
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Abstract
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.
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Affiliation(s)
- Sean Lynch
- Eastern Virginia Medical School, Norfolk, Virginia, USA.
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21
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Abstract
Characterization of iron metabolism in infants and children may be confounded by the diverse effects of developmental, genetic, and acquired influences on iron metabolism and laboratory measurements of iron status, especially in areas with intense perennial transmission of Plasmodium falciparum malaria. In the Pemba iron and folic acid supplementation trial, the coadministration of folic acid with iron is a further confounding factor. Because the design of the Pemba iron and folic acid supplementation study did not include a group that received iron supplementation without folic acid, the observed increase in serious adverse events cannot be ascribed unequivocally to iron alone, to folic acid alone, or to the combination of the two. In interpreting the results from the Pemba iron and folic acid supplementation trial, additional analyses of existing data from the trial and from earlier studies in the area could help clarify the roles of iron and folic acid.
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Affiliation(s)
- Gary M Brittenham
- College of Physicians and Surgeons, Columbia University, New York, USA.
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22
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Olney DK, Pollitt E, Kariger PK, Khalfan SS, Ali NS, Tielsch JM, Sazawal S, Black R, Mast D, Allen LH, Stoltzfus RJ. Young Zanzibari children with iron deficiency, iron deficiency anemia, stunting, or malaria have lower motor activity scores and spend less time in locomotion. J Nutr 2007; 137:2756-62. [PMID: 18029495 DOI: 10.1093/jn/137.12.2756] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Motor activity improves cognitive and social-emotional development through a child's exploration of his or her physical and social environment. This study assessed anemia, iron deficiency, hemoglobin (Hb), length-for-age Z-score (LAZ), and malaria infection as predictors of motor activity in 771 children aged 5-19 mo. Trained observers conducted 2- to 4-h observations of children's motor activity in and around their homes. Binary logistic regression assessed the predictors of any locomotion. Children who did not locomote during the observation (nonmovers) were excluded from further analyses. Linear regression evaluated the predictors of total motor activity (TMA) and time spent in locomotion for all children who locomoted during the observation combined (movers) and then separately for crawlers and walkers. Iron deficiency (77.0%), anemia (58.9%), malaria infection (33.9%), and stunting (34.6%) were prevalent. Iron deficiency with and without anemia, Hb, LAZ, and malaria infection significantly predicted TMA and locomotion in all movers. Malaria infection significantly predicted less TMA and locomotion in crawlers. In walkers, iron deficiency anemia predicted less activity and locomotion, whereas higher Hb and LAZ significantly predicted more activity and locomotion, even after controlling for attained milestone. Improvements in iron status and growth and prevention or effective treatment of malaria may improve children's motor, cognitive, and social-emotional development either directly or through improvements in motor activity. However, the relative importance of these factors is dependent on motor development, with malaria being important for the younger, less developmentally advanced children and Hb and LAZ becoming important as children begin to attain walking skills.
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Affiliation(s)
- Deanna K Olney
- Program in International and Community Nutrition, University of California, Davis, CA 95616, USA.
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23
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Schümann K, Ettle T, Szegner B, Elsenhans B, Solomons NW. On risks and benefits of iron supplementation recommendations for iron intake revisited. J Trace Elem Med Biol 2007; 21:147-68. [PMID: 17697954 DOI: 10.1016/j.jtemb.2007.06.002] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 06/04/2007] [Accepted: 06/11/2007] [Indexed: 12/24/2022]
Abstract
Iron is an essential trace element with a high prevalence of deficiency in infants and in women of reproductive age from developing countries. Iron deficiency is frequently associated with anaemia and, thus, with reduced working capacity and impaired intellectual development. Moreover, the risk for premature delivery, stillbirth and impaired host-defence is increased in iron deficiency. Iron-absorption and -distribution are homeostatically regulated to reduce the risk for deficiency and overload. These mechanisms interact, in part, with the mechanisms of oxidative stress and inflammation and with iron availability to pathogens. In the plasma, fractions of iron may not be bound to transferrin and are hypothesised to participate in atherogenesis. Repleted iron stores and preceding high iron intakes reduce intestinal iron absorption which, however, offers no reliable protection against oral iron overload. Recommendations for dietary iron intake at different life stages are given by the US Food and Nutrition Board (FNB), by FAO/WHO and by the EU Scientific Committee, among others. They are based, on estimates for iron-losses, iron-bioavailability from the diet, and iron-requirements for metabolism and growth. Differences in choice and interpretation of these estimates lead to different recommendations by the different panels which are discussed in detail. Assessment of iron-related risks is based on reports of adverse health effects which were used in the attempts to derive an upper safe level for dietary iron intake. Iron-related harm can be due to direct intestinal damage, to oxidative stress, or to stimulated growth of pathogens. Unfortunately, it is problematic to derive a reproducible cause-effect and dose-response relationship for adverse health effects that suggest a relationship to iron-intake, be they based on mechanistic or epidemiological observations. Corresponding data and interpretations are discussed for the intestinal lumen, the vascular system and for the intracellular and interstitial space, considering interference of the mechanisms of iron homoeostasis as a likely explanation for differences in epidemiological observations.
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Affiliation(s)
- Klaus Schümann
- Science Center Weihenstephan, Technical University Munich, Am Forum 5, D-85350, Freising, Germany.
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24
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Abstract
The prevalence of iron deficiency among infants and young children living in developing countries is high. Because of its chemical properties--namely, its oxidative potential--iron functions in several biological systems that are crucial to human health. Iron, which is not easily eliminated from the body, can also cause harm through oxidative stress, interference with the absorption or metabolism of other nutrients, and suppression of critical enzymatic activities. We reviewed 26 randomized controlled trials of preventive, oral iron supplementation in young children (aged 0-59 mo) living in developing countries to ascertain the associated health benefits and risks. The outcomes investigated were anemia, development, growth, morbidity, and mortality. Initial hemoglobin concentrations and iron status were considered as effect modifiers, although few studies included such subgroup analyses. Among iron-deficient or anemic children, hemoglobin concentrations were improved with iron supplementation. Reductions in cognitive and motor development deficits were observed in iron-deficient or anemic children, particularly with longer-duration, lower-dose regimens. With iron supplementation, weight gains were adversely affected in iron-replete children; the effects on height were inconclusive. Most studies found no effect on morbidity, although few had sample sizes or study designs that were adequate for drawing conclusions. In a malaria-endemic population of Zanzibar, significant increases in serious adverse events were associated with iron supplementation, whereas, in Nepal, no effects on mortality in young children were found. More research is needed in populations affected by HIV and tuberculosis. Iron supplementation in preventive programs may need to be targeted through identification of iron-deficient children.
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Affiliation(s)
- Lora L Iannotti
- Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA
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25
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Olney DK, Pollitt E, Kariger PK, Khalfan SS, Ali NS, Tielsch JM, Sazawal S, Black R, Allen LH, Stoltzfus RJ. Combined iron and folic acid supplementation with or without zinc reduces time to walking unassisted among Zanzibari infants 5- to 11-mo old. J Nutr 2006; 136:2427-34. [PMID: 16920865 DOI: 10.1093/jn/136.9.2427] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Iron and zinc deficiencies have been associated with delayed motor development in nutritionally at-risk children, albeit inconsistently. In this community-based, randomized double-blind trial, iron+folic acid (FeFA) (12.5 mg Fe + 50 mug folic acid), zinc (Zn) (10 mg), and iron+folic acid+zinc (FeFA+Zn) supplements or a placebo were given daily for 1 y to nutritionally at-risk children in Pemba, Zanzibar. The effects of these treatments on attaining unassisted walking were evaluated using survival analysis for 354 children aged 5-11 mo at the start of supplementation. Treatment effects on changes in hemoglobin (Hb) and zinc protoporphyrin (ZPP) and height-for-age (HAZ) and weight-for-age (WAZ) Z scores were evaluated using linear regression. Attained motor milestone was recorded every 2 wk for 1 y. Hb, ZPP, HAZ, and WAZ were measured at baseline and after 6 mo of treatment. FeFA with or without Zn reduced the time it took for children to walk assisted. Children who received any iron walked unassisted sooner than those who received no iron [median difference approximately 15 d, P = 0.035, risk ratio (RR) = 1.28, 95% CI = 1.02, 1.61] and this effect was stronger in those who had iron deficiency anemia (IDA) at baseline (median difference was approximately 30 d; P = 0.002; RR = 1.68; 95% CI = 1.21, 2.32). FeFA alone and Zn alone improved Hb and ZPP compared with placebo. There were no significant treatment effects on changes in HAZ or WAZ. The effects of treatment on time to walking may have been mediated by improvements in iron status or hemoglobin, but were not mediated through improvements in growth.
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Affiliation(s)
- Deanna K Olney
- U.S. Department of Agriculture, ARS-Western Human Nutrition Research Center, Davis, CA, USA
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26
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Abstract
Iron metabolism is essential for cell function and potentially toxic because iron can catalyze oxygen radical production. Malaria-attributable anemia and iron deficiency anemia coincide as being treatable diseases in the developing world. In absolute amounts, more than 95% of Plasmodium metal biochemistry occurs in the acidic digestive vacuole where heme released from hemoglobin catabolism forms heme crystals. The antimalarial quinolines interfere with crystallization. Despite the completion of the Plasmodium genome, many 'gene gaps' exist in components of the metal pathways described in mammalian or yeast cells. Present evidence suggests that parasite bioavailable iron originates from a labile erythrocyte cytosolic pool rather than from abundant heme iron. Indeed the parasite has to make its own heme within two separate organelles, the mitochondrion and the apicomplast. Paradoxically, despite the abundance of iron within the erythrocyte, iron chelators are cytocidal to the Plasmodium parasite. Hemozoin has become a sensitive biomarker for laser desorption mass spectrometry detection of Plasmodium infection in both mice and humans.
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Affiliation(s)
- P F Scholl
- Department of Environmental Health Sciences, Baltimore, MD 21205, USA
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27
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Sazawal S, Black RE, Ramsan M, Chwaya HM, Stoltzfus RJ, Dutta A, Dhingra U, Kabole I, Deb S, Othman MK, Kabole FM. Effects of routine prophylactic supplementation with iron and folic acid on admission to hospital and mortality in preschool children in a high malaria transmission setting: community-based, randomised, placebo-controlled trial. Lancet 2006; 367:133-43. [PMID: 16413877 DOI: 10.1016/s0140-6736(06)67962-2] [Citation(s) in RCA: 654] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Anaemia caused by iron deficiency is common in children younger than age 5 years in eastern Africa. However, there is concern that universal supplementation of children with iron and folic acid in areas of high malaria transmission might be harmful. METHODS We did a randomised, placebo-controlled trial, of children aged 1-35 months and living in Pemba, Zanzibar. We assigned children to daily oral supplementation with: iron (12.5 mg) and folic acid (50 mug; n=7950), iron, folic acid, and zinc (n=8120), or placebo (n=8006); children aged 1-11 months received half the dose. Our primary endpoints were all-cause mortality and admission to hospital. Analyses were by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN59549825. FINDINGS The iron and folic acid-containing groups of the trial were stopped early on Aug 19, 2003, on the recommendation of the data and safety monitoring board. To this date, 24 076 children contributed a follow-up of 25,524 child-years. Those who received iron and folic acid with or without zinc were 12% (95% CI 2-23, p=0.02) more likely to die or need treatment in hospital for an adverse event and 11% (1-23%, p=0.03) more likely to be admitted to hospital; there were also 15% (-7 to 41, p=0.19) more deaths in these groups. INTERPRETATION Routine supplementation with iron and folic acid in preschool children in a population with high rates of malaria can result in an increased risk of severe illness and death. In the presence of an active programme to detect and treat malaria and other infections, iron-deficient and anaemic children can benefit from supplementation. However, supplementation of those who are not iron deficient might be harmful. As such, current guidelines for universal supplementation with iron and folic acid should be revised.
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Affiliation(s)
- Sunil Sazawal
- Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205, USA
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28
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Cusick SE, Tielsch JM, Ramsan M, Jape JK, Sazawal S, Black RE, Stoltzfus RJ. Short-term effects of vitamin A and antimalarial treatment on erythropoiesis in severely anemic Zanzibari preschool children. Am J Clin Nutr 2005; 82:406-12. [PMID: 16087986 DOI: 10.1093/ajcn.82.2.406] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The pathophysiology of anemia in coastal East Africa is complex. Impaired erythropoietin production is one possible mechanism. Plasmodium falciparum malaria has been found to blunt erythropoietin production, whereas vitamin A stimulates erythropoietin production in vitro. OBJECTIVE We investigated the 72-h effects of vitamin A and the antimalarial drug sulfadoxine pyramethamine (SP) on erythropoietin production in severely anemic (hemoglobin < or = 70 g/L) preschool children in Zanzibar, a region of known vitamin A deficiency. We hypothesized that both treatments would stimulate erythropoietin production directly, within 72 h, before a change in hemoglobin would occur. DESIGN One hundred forty-one severely anemic children were identified during the baseline assessment of a morbidity substudy of a community-based micronutrient supplementation trial. All severely anemic children were randomly assigned to receive either vitamin A (100,000 or 200,000 IU depending on age) or SP at baseline; 72 h later they received the opposite treatment plus daily hematinic syrup for 90 d. Erythropoietic and parasitic indicators were assessed at baseline and again after 72 h. RESULTS After 72 h, SP reduced the malaria parasite density (by 5029 parasites/microL; P < 0.001), CRP concentrations (by 10.6 mg/L; P = 0.001), and the proportion of children infected with malaria (by 32.4%; P < 0.001). Vitamin A reduced CRP (by 9.6 mg/L; P = 0.011), serum ferritin (by 18.1 microg/L; P = 0.042), and erythropoietin (by 194.7 mIU/mL; P = 0.011) concentrations and increased the reticulocyte production index (by 0.40; P = 0.041). CONCLUSIONS Contrary to our hypothesis, vitamin A significantly decreased erythropoietin concentration. The most important effect of both vitamin A and SP was the rapid reduction of inflammation. Vitamin A also mobilized iron from stores and stimulated the production of new erythrocytes.
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Affiliation(s)
- Sarah E Cusick
- Center for Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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29
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Cusick SE, Tielsch JM, Ramsan M, Jape JK, Sazawal S, Black RE, Stoltzfus RJ. Short-term effects of vitamin A and antimalarial treatment on erythropoiesis in severely anemic Zanzibari preschool children. Am J Clin Nutr 2005. [DOI: 10.1093/ajcn/82.2.406] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Sarah E Cusick
- From the Center for Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (SEC, JMT, SS, REB, and RJS); the Public Health Laboratory Ivo de Carneri, Wawi, Chake Chake, Pemba Island, Zanzibar, United Republic of Tanzania (MR and JKJ); and the Division of Nutritional Sciences, Cornell University, Ithaca, NY (RJS)
| | - James M Tielsch
- From the Center for Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (SEC, JMT, SS, REB, and RJS); the Public Health Laboratory Ivo de Carneri, Wawi, Chake Chake, Pemba Island, Zanzibar, United Republic of Tanzania (MR and JKJ); and the Division of Nutritional Sciences, Cornell University, Ithaca, NY (RJS)
| | - Mahdi Ramsan
- From the Center for Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (SEC, JMT, SS, REB, and RJS); the Public Health Laboratory Ivo de Carneri, Wawi, Chake Chake, Pemba Island, Zanzibar, United Republic of Tanzania (MR and JKJ); and the Division of Nutritional Sciences, Cornell University, Ithaca, NY (RJS)
| | - Jape K Jape
- From the Center for Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (SEC, JMT, SS, REB, and RJS); the Public Health Laboratory Ivo de Carneri, Wawi, Chake Chake, Pemba Island, Zanzibar, United Republic of Tanzania (MR and JKJ); and the Division of Nutritional Sciences, Cornell University, Ithaca, NY (RJS)
| | - Sunil Sazawal
- From the Center for Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (SEC, JMT, SS, REB, and RJS); the Public Health Laboratory Ivo de Carneri, Wawi, Chake Chake, Pemba Island, Zanzibar, United Republic of Tanzania (MR and JKJ); and the Division of Nutritional Sciences, Cornell University, Ithaca, NY (RJS)
| | - Robert E Black
- From the Center for Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (SEC, JMT, SS, REB, and RJS); the Public Health Laboratory Ivo de Carneri, Wawi, Chake Chake, Pemba Island, Zanzibar, United Republic of Tanzania (MR and JKJ); and the Division of Nutritional Sciences, Cornell University, Ithaca, NY (RJS)
| | - Rebecca J Stoltzfus
- From the Center for Human Nutrition, Department of International Health, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD (SEC, JMT, SS, REB, and RJS); the Public Health Laboratory Ivo de Carneri, Wawi, Chake Chake, Pemba Island, Zanzibar, United Republic of Tanzania (MR and JKJ); and the Division of Nutritional Sciences, Cornell University, Ithaca, NY (RJS)
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