**Iron Deficiency and Iron Deficiency Anemia in Children**

Roberto Miniero, Valentina Talarico, Maria Concetta Galati, Laura Giancotti, Paola Saracco and Giuseppe Raiola

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/intechopen.79790

### **Abstract**

Iron deficiency anemia is considered the most common and widespread nutritional form of anemia in childhood. Red cells are hypochromic and microcytic with low mean corpuscular volume (MCV), low mean corpuscular hemoglobin (MCH) and low reticulocyte hemoglobin content (CHr). Red blood cell distribution width (RDW) is increased. Serum iron is reduced, transferrin is increased and serum ferritin is decreased. Prematurity, decreased dietary source, malabsorption and blood loss represent the most common causes of iron deficiency. Recommended oral dose of elemental iron is 2–6 mg/kg/day; when normal hemoglobin values are reached, treatment must be generally continued for 3 months in order to replenish iron stores. Rarely intravenous therapy is required. The pediatricians and other health care providers should strive to prevent and eliminate iron deficiency and iron-deficiency anemia.-

**Keywords:** iron deficiency, anemia, children, hypochromic microcytic anemia, prevention-

### **1. Introduction**

In children, iron represents an essential nutrient for growth and proper function of many organs and systems, mainly erythropoiesis. It must be obtained from the diet and absorbed in the upper gastrointestinal tract. When iron requirements are not met, as when the balance of iron intake, iron stores and the body's loss are insufficient to fully support the production of erythrocytes, it is referred to as iron deficiency (ID). In 30% of cases, the ID, if left untreated, evolves in iron deficiency anemia (IDA) which represents the most frequent form of anemia in childhood.-

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### **2. Epidemiology**

ID and IDA are among the most widespread morbid conditions in the world and represent a public health problem both in developed and developing countries. All reports agree that IDA is the most common anemia worldwide in school-age children. A recent WHO report, obtained from 200 countries, showed a significant reduction in prevalence of ID/IDA that rose from 40.2% in 1990 to 32.9% in 2010. In countries with limited resources, ID affects about twothirds of children and adolescents; it is estimated that around 25% of preschool children suffers from IDA. In Africa, the prevalence of IDA among school-age children still ranges from 64.3 to 71%. In Europe, the overall prevalence of ID/IDA is 2–4%, with two peaks between the first and third year of life (2.3–15%) and adolescence (3.5–13% in males, 11–33% in females). ID/IDA is less than 5% in Northern and Western Europe, but it is considerably higher in Eastern Europe (9–50%). In the United States, IDA prevalence is 1.6–7.4% among pediatric population; in children 1–5 years old, the prevalence of ID is 7–8% and about one-third of them have IDA. The prevalence is higher among children 1–2 years old (13.5 and 2.7%, respectively). Although the prevalence of IDA has decreased over the past decade, data from many surveys indicate that it remains relatively high among low-income family; the prevalence of ID/IDA was 17% in 1–2 years old and 6% in 3–4 years old among Mexican American toddlers, and 12% in 1–2 years old and 5% in 3–4 years old in other low-income family [1–7].-

### **3. Pathophysiology**

The amount of iron contained in the body, in relation to the various ages, is summarized in **Table 1**. During the first year of life, total-body iron increases by 240mg; nearly 80% of that iron is used for- expanded hemoglobin production (50%) and iron stores (30%). Over this age, iron intake or stores- must remain sufficient for the ongoing growth and increased red cell mass. Iron metabolism is- essentially a "closed system" in which almost all metal from the hemocateresis (about 95%) is continuously recycled to meet the demands of the various compartments, especially the production of- new red blood cells (RBC). Only a small part of the body iron is represented by that absorbed from- the diet. In adults, less than 5% of the iron requirement for the erythropoiesis is obtained from food- while in the child the iron destined for hemoglobin synthesis derives for 30% from the diet; the- remainder part come from the deposits and the rework of the iron released by the hemocateresis.- From the sixth month, the total body iron progressively increases (70%) to answer to the high rate-


**Table 1.** Iron content in the body in newborn, child and adult.-

of growth and the expansion of the erythrocyte mass. As more than 60% of the iron absorbed is- destined to this function (1kg of weight corresponds to 75ml of blood or 9g of hemoglobin and- 30mg of iron). It is clear that in this age, iron balance is more precarious, and possible dietary- imbalances could reduce tolerance limits (delayed weaning, vegetarian diet and malabsorption).-

Physiological losses are minimal (about 0.5–1 mg/day) and are mostly due to exfoliation of the mucous membranes (bile, intestine, kidneys and lungs) and of the skin. Since there are no specific mechanisms of iron excretion through the liver or kidneys, iron balance is mainly controlled at the intestinal level by modulating its absorption. A balanced diet of an adult contains about 10–15 mg of iron. The absorption of iron in the foods, which varies from 5 to 15% (up to 20% for the meal), compensates the physiological losses. In case of blood losses (menstruation or other bleeding), acute or chronic hemolytic events, or periods of increased demand, such as rapid growth, pregnancy and competitive sports activity, intestinal absorption can increase up to four times.-

Regarding the developmental age, the iron requirement (LARN 2014) to be taken with the diet, after 6 months is about 7–11 mg/day which corresponds to about 0.8–1 mg of iron absorbed. Of these, around 75% are used for growth and 25% to offset the losses. In adolescent age, after the appearance of the menarche (considering that with each menstrual cycle are lost about 10–25 mg of iron), the amount to be taken with the diet rises to 13–18 mg/day [6–15].-

### **4. Etiology**

The causes of iron deficiency are numerous, but in the children, these are basically due to four causes: decreased reserves at birth, inadequate intake with the diet, reduced intestinal absorption or chronic losses of blood. **Table 2** examines all causes [1–4]. "Physiological anemia"

**Blood loss:** abundant and/or frequent menstruation, intolerance of cow's milk protein, consumption more than 500 ml/day of cow-milk, Meckel's diverticulum, esophageal varices, polyps and hemorrhoids, intestinal bowel disease, intestinal parasitosis, epistaxis, severe hematuria, prolonged use of aspirin, cortisones, nonsteroidal antiinflammatory drugs, frequent blood sampling for diagnostic purposes (in the newborn, especially if immature, and in the small infant).-

**Hereditary forms (rare diseases):** DMT1 deficiency, transferrin deficiency, refractory iron deficiency anemia (IRIDA).-

**Chronic pulmonary diseases:** pulmonary hemosiderosis, cystic fibrosis, bronchopulmonary dysplasia.-

**Iron deficiency anemia associated with anemia of chronic diseases.-**

**Table 2.** Main causes of iron deficiency in childhood and adolescence.-

**Decreased reserves at birth:** prematurity and/or twinning, intrauterine fetus-fetal and fetus-maternal transfusions, exanguino-transfusion at birth or severe IDA in the mother, early clamping of the umbilical cord.-

**Inadequate intake:** late weaning, incongruous diet (uncontrolled vegetarian-vegan) and/or increased needs: rapid weight-growth such as low birth weight, prematurity, adolescent development and cyanotic heart disease.-

**Reduced absorption:** celiac disease, intestinal bowel disease, Hirschsprung disease, large intestinal resections (short- bowel), use of antacids and proton pump inhibitors, excess in the diet of phytates (soy and cereals), bran, starch,- calcium, polyphenols (tea and coffee), soy protein, casein and egg white, *Helicobacter pylori* infection, giardiasis and other- intestinal parasites, obesity, bariatric surgery, immune deficiencies with mucosal atrophy, intestinal lymphangiectasia.-

develops in the postnatal period, and iron stores are sufficient to provide erythropoiesis in the first 6 months of life if there is no significant blood loss. In low birth weight infants and in babies with perinatal blood loss, the stores are exhausted earlier. The amount of iron in breast milk is at the highest level in the first month, but it decreases gradually in the subsequent periods and is reduced up to 0.3 mg/l approximately in the fifth month. Although the amount of iron received from breast milk is typically low, its absorption is considerably high (50%). Solid foods, given after the sixth month, should be rich especially in iron, zinc, phosphorus, magnesium, calcium and vitamin B6. According to the WHO data, 98% of the iron requirement in infants aged 6–23 months should be introduced by solid foods. In patients, especially in older children and adolescents, blood losses should be considered, if inadequate intake can be excluded or there is inadequate response to iron treatment.-
