|Year : 2017 | Volume
| Issue : 1 | Page : 37-43
Hypochromic microcytic anemia: a clincopathological cross-sectional study
Mostafa A.S Salama1, Maha Y Kamal1, Doren N.A Younan2, Gehad A.A Henish1
1 Department of Pediatric Hematology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
2 Department of Clinical Pathology, Faculty of Medicine, Alexandria University, Alexandria, Egypt
|Date of Submission||29-Mar-2017|
|Date of Acceptance||22-Apr-2017|
|Date of Web Publication||12-Jul-2017|
Maha Y Kamal
Doctor Degree in Pediatrics, MSc. Alexandria University, MBCHB Alexandria University
Source of Support: None, Conflict of Interest: None
Background Iron-deficiency anemia, the most common cause of microcytic anemia, is a worldwide nutritional problem; its prevalence in the developing countries is three times higher than in the developed countries. It is a common disease in Egypt with a very high prevalence rate. It affects all age groups and all socioeconomic levels of the society. Identification of infants who are at risk for iron deficiency anemia (IDA) is vital as it impairs psychomotor development and growth and reduces physical activity and resistance to infection.
Aim The aim of this work was to assess the prevalence of IDA among infants aged 6 months and 2 years presenting with hypochromic microcytic anemia and to determine the risk factors of iron deficiency among this age group.
Participant and methods A total of 40 infants (6 months and 2 years) presenting with hypochromic microcytic anemia attending Alexandria University Children’s Hospital were included in this study. All were subjected to complete blood count, iron profile [serum ferritin (SF), serum iron, and total iron-binding capacity], and finding occult blood in stool. Those having normal iron profile were further subjected to capillary hemoglobin (Hb) electrophoresis and PCR for α-chain gene mutations to exclude β-thalassemias and α-thalassemias.
Results Overall, 77.5% (31/40) of the studied infants had IDA, which represents the main cause of microcytic anemia in this study, whereas 17.5% (7/40) had β-thalassemia trait, diagnosed by increased HbA2 more than 3.5% by capillary Hb electrophoresis, and 5% (2/40) had α-thalassemia trait of the homozygous α3.7 (−α3.7/−α3.7) deletional type, detected by PCR for α-gene mutations. Moreover, this study showed that infants with IDA had significantly higher frequencies of preterm deliveries (48.38%) compared with β-thalassemia trait (14.28%), and α-thalassemia trait (0%), P=0.023, KWχ2=4.849. A significant positive correlation was found between Hb, serum iron, and SF levels of infants with IDA and both maternal Hb during pregnancy (r=0.937, P<0.001; rs=0.796, P<0.001; and rs=0.780, P<0.001, respectively) and maternal age (r=0.791, P<0.001; rs=0.749, P<0.001; and rs=0.671, P<0.001, respectively). The mean±SD weight of infants with IDA (9.91±1.61 kg) was significantly lower than that of infants having other microcytic anemias, P=0.039, KWχ2=5.659. Among infants with IDA, only five started weaning at an appropriate age, i.e., between 4 and 6 months, and their SF levels ranged between 8 and 9.4 μg/l, with a mean±SD of 8.58±1.10, which was statistically significantly higher than the SF levels among those who started weaning later (>6 months) (n=26), whose SF levels ranged between 2.0 and 5.9 μg/l, with a mean±SD of 4.04±1.10, P=0.001.
Conclusion High prevalence of IDA was detected among infants presenting with microcytic hypochromic anemia (77.5%). The main risk factors for developing IDA include inadequate iron intake, preterm delivery, delayed onset of weaning, occult blood loss in stools owing to either early introduction of cow’s milk or parasitic infestations, and finally, infants born to young or anemic mothers.
Keywords: egyptians, hypochromic microcytic anemia, infants, iron-deficiency anemia
|How to cite this article:|
Salama MA, Kamal MY, Younan DN, Henish GA. Hypochromic microcytic anemia: a clincopathological cross-sectional study. Alex J Pediatr 2017;30:37-43
|How to cite this URL:|
Salama MA, Kamal MY, Younan DN, Henish GA. Hypochromic microcytic anemia: a clincopathological cross-sectional study. Alex J Pediatr [serial online] 2017 [cited 2018 Nov 13];30:37-43. Available from: http://www.ajp.eg.net/text.asp?2017/30/1/37/210443
| Introduction|| |
Anemia is a public health problem affecting both developing and developed countries all over the world. According to the WHO, globally it affects 1.62 billion people; this corresponds to 24.8% of the population, with the highest prevalence among infants (6–24 months) and preschool age children .
Microcytic anemia, mean corpuscular volume (MCV) less than 75 fl, is the most common form of anemia in children, which has several etiologies as shown in [Table 1].
Iron-deficiency anemia, the most common cause of microcytic anemia, is a worldwide nutritional problem. Egypt Demographic Health Survey (2005) reported a 48.5% prevalence of iron deficiency anemia (IDA) among Egyptian children and 26.6% among Egyptian adults ,. Infants aged 6–24 months constitute one of the highest risk groups of iron deficiency . Inadequate iron intake in diet is the most common cause of iron deficiency in children .
Recent studies suggest the use of red blood cell indices obtained from automated cell counter, including mean corpuscular Hb (MCH), MCV, and red cell distribution width (RDW), to predict IDA, as they have become very sensitive indicators of IDA . The reticulocyte count is decreased in IDA as it reflects the state of erythroid activity of the bone marrow .
Regarding the iron profile, iron deficiency is strongly suggested when serum iron (SI) level is less than 30 μg/dl and total iron-binding capacity (TIBC) is more than 400 μg/dl . Serum ferritin (SF) level represents the earliest sensitive indicator of early iron deficiency . Transferrin saturation (<12%) is not an early detector for iron deficiency, as when a decrease in its level occurs, iron stores are already exhausted . Absence of stainable bone marrow is a remarkable indicator of early iron depletion states .
It is important to distinguish between IDA and β-thalassemia trait to avoid unnecessary iron therapy and the development of hemosiderosis (iron overload) . In the diagnosis of β-thalassemia trait, hemoglobin (Hb) electrophoresis shows elevated HbA2 more than 3.5% and HbF . Patients with α-thalassemia trait have normal Hb electrophoresis result .
A transferrinemia is a rare hereditary disorder characterized by iron overload and microcytic anemia. It must be differentiated from IDA . Anemia of chronic disease is suggested with low SI levels and decreased TIBC .
| Aim|| |
The aim of this work was to assess the prevalence of IDA among infants aged 6 months and 2 years presenting with hypochromic microcytic anemia and to determine the risk factors of iron deficiency among this age group.
| Participants and methods|| |
This study was conducted on 40 infants (6 months and 2 years) presenting with hypochromic microcytic anemia at Alexandria University Children’s Hospital. All parents signed a written informed consent form according to the Ethics Committee for Human Resources of Alexandria Faculty of Medicine.
Children on iron supplementation, with previous history of blood transfusion, with long-term or recent illness (cardiac, renal, hepatic, or tuberculosis), or having family history of blood diseases were all excluded from the present study.
All infants, included in this study, were subjected to the following:
- Personal history questionnaire [name, age, sex, and gestational age (GA)].
- Anthropometric measurements [length (cm) and weight (kg)].
- History of bleeding from any site (nose, mouth, gastrointestinal tract, or rectum).
- Full dietary history: type of milk feeding during first 6 months of life, age of start of weaning [age of introduction of complementary food especially those with high iron content], food frequency questionnaire and type of food supplementation to assess iron intake, and history of previous iron intake.
- Daily iron intake of each infant was calculated using Diet Analysis Program (DAP), 1995 (Lifestyles Technologies Inc., Northbridge Point, Valencia, California, USA) and was then compared with the recommended daily allowance (RDA), according to the infant’s age .
- Complete blood count:
- All the infants under study presented with hypochromic microcytic anemia (MCV <75 fl, MCH <27 pg, and RDW >14%) on their complete blood count using Coulter 1660 (Beckman Coulter Life Sciences, Indianapolis, USA). Reticulocytosis occurs in hemolytic anemia with microcytosis (β-thalassemia) and decreased in IDA.
- SF, serum iron, and TIBC:
- The sera were further evaluated for SF by Immulite 1000 (Siemens, Munich, Germany), a chemiluminescent immunemetric assay. IDA was diagnosed at SF value less than 10 µg/l .
- Occult blood in stool:
- Occult blood in stool was detected by Guaiac stool test. It is a diagnostic test of gastrointestinal tract blood loss induced by early introduction of cow’s milk in infants causing IDA.
- Capillary hemoglobin electrophoresis:
- Capillary Hb electrophoresis was performed using the Sebia Minicap (Capillarys System, Evry Cedex, France), which provides a fast separation and quantitation of different Hb fractions. β-Thalassemia trait is diagnosed when HbA2 is more than 3.5%.
- PCR for α-chain gene mutations:
- A reverse-hybridization assay (α-globin strip assay kit, catalog no. 4–160/4–161) from Vienna lab (Labor Diagnostika GmbH; Vienna lab, COMPIEGNE, France) was used for the simultaneous screening of 21 deletional and nondeletional α-globin gene mutations in a single procedure.
- For each point mutation or small deletion, one of three possible staining patterns is obtained:
- Wild-type probe positive: normal genotype.
- Wild-type and mutant probe positive: heterozygous genotype (carrier individual).
- Mutant probe positive: homozygous mutant genotype (affected individual).
- Statistical analysis of the data:
- Data were fed to the computer and analyzed using IBM SPSS software package version 20.0 (Quarry Bay, Hong Kong). Qualitative data were described using number and percentage. Quantitative data were described using range (minimum and maximum), mean, SD, and median. The distributions of quantitative variables were tested for normality using Kolmogorov–Smirnov test. If it revealed normal data distribution, parametric tests were applied. If the data were not normally distributed, nonparametric tests were used. For normally distributed data, comparison between two independent populations was done using independent t-test. Mann–Whitney test was used when variables are not normally distributed. Pearson’s and Spearman’s correlation coefficient tests were used accordingly. P value less than 0.05 was considered significant.
| Results|| |
Present study was conducted on 40 infants, all having microcytic (MCV <76 fl), hypochromic (MCH <27 pg) anemia (Hb <11 g/dl): 22 (55%) males and 18 (45%) females. Their ages ranged between 9 months and 2 years, with a mean of 19.68±5.28 months. Of them, 16 (40%) were born preterm (before 37 weeks gestation). During their first 6 months of life, 50% (20/40) of them were exclusively breast fed (BF), whereas 7.5% (3/40) were exclusively on milk formula. The rest (42.5%, 17/40) were on mixed regimens: BF+cow’s milk, or BF+formula, or cow’s milk+formula. The age of introduction of cow’s milk ranged between 2 and 12 months, with a mean of 8.4±2.88 months.
Regarding the age of starting weaning (age of itroduction of complementary food), it ranged between 6 months and 2 years, with a mean of 14.64±3.48 months. Overall, 45% (18/40) started weaning at 6 months, which was appropriate; however, the remaining 55% started later (after 6 months).
Overall, 85% (34/40) gave no history of bleeding, whereas the remaining 15% (6/40) had history of bleeeding through rectum. Occult blood in stool was positive in 15 of 40 infants (37.5%), all of whom gave history of introduction of cow’s milk or its products at a significantly earlier age, with mean of 5.76±2.52 months, than those negative for oocult blood in stool, with mean of 9.96±1.92 months, P less than 0.001 ([Table 2]).
|Table 2 Relation between occult blood in stool and age of introduction of cow’s milk products in infants with iron-deficiency anemia|
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Moreover, 75% (30/40) had no history of parasitic infestation, whereas 25% (10/40) were positive for either Entamoeba histolytica (vegetative form) (7/40), ascaris (2/40), or giardia (1/40).
Overall, 60% of the studied infants had severe dietary iron deficiency according to DAP when compared with RDA, 27.5% had moderate dietary iron deficiency, and only 12.5% had adequate dietary iron intake, as shown in [Table 3].
|Table 3 Distribution of the studied cases (n=40) according to estimated adequacy of daily iron intake according to Diet Analysis Programe and recommended daily allowance|
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In our study, infants with anemia were considered to be iron deficient when SI level was less than 40 μg/dl, SF level less than 12 μg/l±low SI less than 50 μg/dl, and TIBC level was more than 400 μg/dl according to WHO 2004 .
Overall, 77.5% (31/40) of the studied infants had IDA which represents the main cause of microcytic anemia in this study, whereas 17.5% (7/40) had β-thalassemia trait, diagnosed by increased HbA2 more than 3.5% by capillary Hb electrophoresis, and 5% (2/40) had α-thalassemia trait of the homozygous α3.7 (−α3.7/−α3.7) deletional type, detected by PCR for α-gene mutations. Infants having IDA and those having α-thalassemia trait showed normal Hb profile by capillary Hb electrophoresis.
Among infants with IDA, SI level ranged between 6 and 33 μg/dl, with a mean±SD of 23.52±7.87; SF level ranged between 2 and 6 μg/l, with a mean±SD of 4.19±1.05; and TIBC ranged between 430 and 640 μg/dl, with a mean±SD of 485.68±56.14.
Moreover, this study showed that infants with IDA had significantly higher frequencies of preterm deliveries (48.38%) compared with β-thalassemia trait (14.28%), and α-thalassemia trait (0%), P=0.023, KWχ2=4.849. Using Spearman’s ρ and Pearson’s correlation study, significant positive correlation was found between Hb, SI, and SF levels of infants with IDA and both maternal Hb during pregnancy (r=0.937, P<0.001; rs=0.796, P<0.001; and rs=0.780, P<0.001) and maternal age (r=0.791, P<0.001; rs=0.749, P<0.001; and rs=0.671, P<0.001).
Moreover, significant negative correlation was found between their TIBC levels and both maternal Hb during pregnancy (r=−0.662, P<0.001) and maternal age (r=−0.546, P<0.001), as shown in [Table 4].
|Table 4 Correlation between hemoglobin and iron status of infants with iron-deficiency anemia and maternal hemoglobin during pregnancy and maternal age|
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The mean±SD weight of infants with IDA was 9.91±1.61 kg, which was significantly lower than that of infants having other microcytic anemias, P=0.039, KWχ2=5.659.
Among infants with IDA, only five started weaning at an appropriate age, i.e., between 4 and 6 months, and their SF levels ranged between 8 and 9.4 µg/l, with a mean±SD of 8.58±1.10, which was statistically significantly higher than the SF levels among those who started weaning later (>6 months) (n=26), whose SF levels ranged between 2.0 and 5.9 μg/l, with a mean±SD of 4.04±1.10 (P=0.001) as shown in [Table 5].
|Table 5 Relation between age of start of weaning in infants with iron-deficiency anemia and serum ferritin level|
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Infants with IDA had significantly lower Hb levels, hematocrit percentage, red blood cell counts, and reticulocyte percentage than their thalassemic counterparts, with P values of 0.019, 0.020, less than 0.001, and 0.001, respectively. However, they had significantly higher RDW% and platelet counts (P<0.001 and 0.002, respectively).
| Discussion|| |
The higher frequency of IDA among predominantly BF infants compared with formula-fed infants may be surprising. These findings are similar to those obtained by Monterrosa et al.  and Gong et al.  who reported that predominantly BF from birth to 6 months was associated with increased risk for IDA among infants. On the contrary, Konstantyner et al.  reported that exclusively BF in the first 4 months of life had a protective effect against anemia and IDA.
The results of the present study showed significant early introduction of cow᾽s milk products among the infants with IDA, which constituted an important risk factor of IDA, presenting as occult blood in stools in ∼38% of the studied infants included in this study, with a mean age±SD of 8.4±2.88 months. The same was documented by Hopkins et al.  and Fernandes  who found that there was strong association between cow’s milk consumption during the first year of life and development of IDA, which was related to occult blood loss through stool owing to allergy toward cow’s milk protein, low bioavailability of cow’s milk iron (10%), and its interference with iron absorption from food.
Findings of the present study demonstrated high prevalence of IDA, present in 77.5% of infants presenting with microcytic hypochromic, i.e., IDA was proved to be the dominant cause of microcytic anemia in Egypt. These findings are in accordance with those of Carvalho et al.  and Lawson et al.  from Brazil who found that prevalence of IDA was 60% among infants with microcytic anemias. Moreover, WHO 2008  documented that it is generally assumed that 50% of the cases of anemia are owing to iron deficiency, reaching up 70% in the developing countries.
Current study clearly shows that IDA is a severe public health problem among infants aged 6–24 months in Egypt according to the classification of WHO 2001  of populations in relation to the level of public health significance of anemia: a prevalence of less than 19.9% is low, 20–39.9% is moderate, and 40% or mare is severe.
The prevalence of IDA varies widely depending on the socioeconomic status and population culture. Much lower frequencies of IDA were reported in the developed countries including Ireland  (2.6–9.2%), Greece  (8%), and Canada  (7%).
The frequency of β-thalassemia trait, in our study, was 17.5%. These findings are similar to those of Hussein et al.  who reported that the estimated β-thalassemia trait in Egypt in 2007 was 12%. Regarding the prevalence of β-thalassemia trait worldwide, Guler et al.  found that its rate was 2.1% in Turkey, and Tympa-Psirropoulou et al.  found that its rate was 2.13% in Greece.
In this study, the frequency of α-thalassemia trait was two of 40 infants, representing 5%. These two infants were of the homozygous α3.7 (−α3.7/−α3.7) deletional type. These findings are near to those obtained by Lafferty et al.  in Ontario, Canada, and Neishabury et al.  in Iran, who reported that the frequencies of α-thalassemia trait were 5.5 and 5.7%, respectively, also having the homozygous α3.7 (−α3.7/−α3.7) deletional type.
Infancy is a high risk factor of IDA, as has been shown in this study that infants with IDA had significantly high frequencies of preterm deliveries 48.38%, P=0.023, KWχ2=4.849. In accordance with these findings, McQueen et al.  and Rao et al.  reported that premature infants are at risk for early postnatal iron deficiency because of decreased iron stores at birth and increased demand for catch-up growth.
In this study, almost 74.2% of infants with IDA had a significantly low daily iron intake and met less than 50% of the RDA according to DAP when compared with β-thalassemia and α-thalassemia trait, MCP less than 0.001, χ2=22.898, P1 less than 0.001, respectively. These findings agree with the WHO 2001  and Thankachan et al. , reporting that iron deficiency of dietary origin seems to be the main cause of anemia and is attributable to poor nutritional iron intake.
Findings of the present study showed that infants with IDA received mixed regimen in their first 6 months of life and had significantly affected iron status when compared with those who received exclusive milk formula and were exclusively BF. These findings are in accordance with Hopkins et al.  and Pusic et al.  who stated that type of milk feeding in the first 6 months of life had an important effect on iron stores and development of IDA especially mixed milk formula with cows᾽ milk as a common cofactor, which was commonly given to infants with IDA included in our study (48.4%).
In the present study, SF level was significantly affected (4.04±1.10 μg/dl) in infants with late onset of weaning (delayed age of introduction of CF >6 months), ∼84% (26/31) of those having IDA. These findings correlate with those of Hopkins et al.  who reported that age at onset of weaning is one of the most important risk factors affecting iron stores, as iron stores depletion at 4–6 months of age was documented especially with exclusive BF infants without iron supplementation and delayed introduction of CF especially high iron content in diet.
Additional analyses of this surveillance revealed that infants born to mothers with anemia and infants of young mothers had lower iron stores. These results are in accordance with a surveillance done by De Pee et al.  among Indonesian infants, which revealed that the high prevalence of IDA among Indonesian infants was related to maternal anemia which was mainly owing to iron deficiency and the mothers’ inability to meet the high nutritional demands of pregnancy.
The diagnosis of IDA warrants additional evaluation for an underlying cause; nutritional deficiency and blood loss with cow’s milk intolerance are the most common causes of IDA among infants. Significant iron loss requires replacement with iron supplements. It is necessary to replete iron stores in addition to correction of the anemia.
- IDA is still a severe public health problem among infants in Egypt.
- Main goals of prevention of IDA that should be implemented include (a) maintaining breast feeding for at least 6 months, if possible; (b) using an iron-fortified infant formula, if a formula is used, and using formula in preference to cow’s milk; (c) using iron-fortified infant cereals as one of the first solid feeds; and (d) providing supplemental iron for low-birth-weight infants.
- Cow’s milk should not be given to a baby younger than 12 months.
- Early detection and control of parasitic infestation is a recommended aspect in prevention of iron deficiency.
- It is crucial to differentiate between IDA and β-thalassemia to avoid wrong interventional therapy.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Benoist B, McLean E, Cogswell M. Worldwide prevalence of anemia 1993–2005: WHO Glob Database Anemia 2008; 440:516.
Clark SF. Iron deficiency anemia: diagnosis and management. Curr Opin Gastroenterol 2009; 25:122–128.
Hartman KR, Barker JA. Microcytic anemia with iron malabsorption: an inherited disorder of iron metabolism. Am J Hematol 1996; 51:269–275.
Finberg KE. Iron-refractory iron deficiency anemia. Semin Hematol 2009; 46:378–386.
Scott PJ. Iron deficiency anemia. In: Behrman RE, Kliegman RM, editors. Nelson text book of pediatrics. 19th ed. Canada: WB Saunders Company; 2007. pp. 1655–1657.
Williams JA, Leveine JE. Sickle cell disease. In: Burg FD, Gershon AA, editors. Gellis and Kagan᾽s current pediatric therapy. 17th ed. Philadelphia: WB Saunders; 2002. pp. 648–650
Supaj R. Iron deficiency anemia: Oxford handbook of clinical medicine. 6th ed. London: Oxford University Press; 2004. pp. 626–628.
Aslan D, Crain K, Beutler E. A new case of human atransferrinemia with a previously undescribed mutation in the transferrin gene. Acta Haematol 2007; 118:244–247.
El Shan F. Anemia among Egyptian adolescents: prevalence and determinants. East Mediterr Health J 2000; 6:1017–1025.
El Zanaty F, Way A. Egypt demographic health survey. Ministry of Health and Population, National Population Council; 2005.
Carvalho AG, Lira PI, Barros MF. Diagnosis of iron deficiency anemia in children of Northeast Brazil. Rev Saude Publica 2010; 44:513–519.
Lozoff B. Iron deficiency and child development. Food Nutr Bull 2007; 28:560–571.
Daniel HR. Examination of the blood: Williams hematology. 7th ed. USA: The McGraw Hill Companies; 2005. pp. 9–17
Al Buhairan AM, Oluboyede OA. Determinant of serum iron, total iron binding capacity and serum ferritin. Ann Saudi Med 2001; 21:100–103.
McPherson RA, Pincus MR. Iron deficiency anemia: Henry’s clinical diagnosis and management laboratory methods. 21th ed. Philadelphia: WB Saunders; 2007. pp. 455–482.
Bain BJ. Bone marrow biopsy morbidity. J Clin Pathol 2005; 58:406–408.
Weatheral DJ, Clegg J. The thalassemia syndromes 4th ed. Melbourne: Blackwell Scientific Publications; 2001. pp. 260–275.
Thein SL. Pathophysiology of β and α-thalassemia: a guide to molecular therapies. Hematology Am Soc Hematol Educ Program 2005; pp. 31–37.
Longo DL. Harrison’s hematology and oncology. 2nd ed. USA: McGraw-Hill Professional; 2013. pp. 57–53.
Gong YH, Zheng XX, Shan JP. Correlation of 4-month infant feeding modes with their growth and iron status. Chin Med J 2008; 121:392–398.
Monterrosa EC, Frongillo EA, Vásquez-Garibay EM. Predominant breast-feeding from birth to six months is associated with fewer gastrointestinal infections and increased risk for iron deficiency among infants. J Nutr 2008; 138:1499–1504.
Fernandes SM, De Morais MB, Amancio OM. Intestinal blood loss as an aggravating factor of iron deficiency in infants aged 9 to 12 months fed whole cow’s milk. J Clin Gastroenterol 2008; 42:152–156.
Muniz PT, Castro TG. Satide e nutricao infantile na Amazonia Ocidental Brasileira: inqueritos de base populacional em dois municipios acreanos. Cad Saude Publica 2007; 23:1283–1293.
World Health Organization. Iron deficiency anemia: assessment, prevention and control. United Nations Children’s Fund, United Nations University; 2001.
Lawson MS, Thomas M, Hardiman A. Iron status of Asian children aged 2 years living in England. Arch Dis Child 1998; 78:420–426.
Tympa-Psirropoulou E, Vagenas C. Environmental risk factors for iron deficiency anemia in children 12–24 months old in the area of Thessalia in Greece. Hippokratia 2008; 12:240–250.
Innis SM, Nelson CM, Wadsworth LD. Incidence of iron deficiency anemia and depleted iron stores among 9-month old infants in Vancouver, Canada. Revue Canadienne de Sante Publique 1997; 88:80–84
Hussein G, Serail I. Thalassemia prevalence and status in Egypt. Hemoglobin 2007; 31:49–62
Guler E, Garipardic M, Dalkiran T. Premarital screening test results for β-thalassemia and sickle cell anemia trait in east Mediterranean region of Turkey. Pediatr Hematol Oncol 2010; 27:608–613.
Lafferty JD, Barth DS, Sheridan BL. Prevalence of thalassemia in patients with microcytosis referred for hemoglobinopathy investigation in Ontario. Am J Clin Pathol 2007; 127:192–196.
Neishabury M, Abbasi-Moheb L, Poorfathollah K. α-Thalassemia: deletion analysis in Iran. Arch Irn Med 2001; 4:160–164
Mc Queen FR. Pediatric and geriatric hematology. In: Rodak BF, Fritsma GA, editors. Hematology: clinical principles and applications. 3rd ed. St. Louis, MO: Elsevier 2007. pp. 526–540.
Rao R, Georgieff MK. Microminerals. In: Tsang RC, Uauy R, editors. Nutrition of the preterm infant: scientific basis and practical guidelines. 2nd ed. Cincinnati, OH: Digital Educational Publishing Inc.; 2005. 277–310
Thankachan P, Walczyk T, Muthayya S. Iron absorption in young Indian women: the interaction of iron status with the influence of tea and ascorbic acid. Am J Clin Nutr 2008; 87:881–886.
Pusic MV, Dawyduk BJ, Mitchell D. Opportunistic screening for iron deficiency in 6–36 months old children presenting to the pediatric emergency department. BMC Pediatr 2005; 5:42.
De Pee S, Bloem MW, Sari M. The high prevalence of low hemoglobin concentration among Indonesian infants is related to maternal anemia. J Nutr 2002; 132:2215–2221.
Maldona JL, Baro L, Gil F. Intake of an iron supplemented milk formula as a preventive measure to avoid low iron status in 1-3 year olds. An Pediatr (Barc) 2007; 66:591–596.
Huong TL, Brouwer ID, Khan CN. Suitability of instant noodles for iron fortification to combat iron deficiency anemia among primary schoolchildren in rural Vietnam. Food Nun Bull 2007; 28:291–298.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]