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Get this from a library! Anemias carenciais e gravidez.. [Clovis Antonio Bacha]. 7 jun. Estudo realizado na Índia mostrou prevalência de anemia de 45% em adolescentes do sexo feminino. Na Indonésia . Anemias carenciais. 11 jun. A anemia por deficiência de ferro configura um problema epidemiológico da maior relevância atuando nos gastos públicos de saúde, nas.

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Iron deficiency anemia in adolescents; a literature review. Anemia por deficiencia de hierro en adolescentes; una revision de la literatura. Pediatrician, Emergency Department, Hospital Alianga. Anemia is one of the most careciais nutritional deficiencies affecting various social carenclais socioeconomic strata. It is more common in developing countries, with children and adolescents being at a significantly higher risk for the condition. To perform a literature review on iron deficiency anemia in adolescence as a public health qnemias and on the risk factors that may contribute towards nutritional deficiencies, stunted growth and development in this age group, emphasizing the physiopathology and causes of anemia, the different diagnostic approaches, and its clinical characteristics, prevention and treatment.

Scientific papers published in Spanish, Portuguese or English between and on the subject aenmias iron deficiency anemia in adolescents were selected for inclusion.

A total of studies carencixis between January 1 stand June 30 thwere identified and evaluated. Forty-two articles meeting the inclusion criterion adolescents with anemia were selected for this review. Finally, an analysis was conducted and the papers were evaluated in accordance with the study objectives.

Preventive action is required with respect to iron deficiency anemia. Healthcare professionals should be aware of the need for early diagnosis, prophylaxis and treatment. Se identificaron y evaluaron un total de estudios publicados entre el 1 o de enero de y anemiad 30 de junio de Red cell distribution width.

Carnciais is a term given to a pathological process in which erythrocyte hemoglobin Hbhematocrit Ht and the concentration of red abemias cells per unit of volume are abnormally low compared to the peripheral blood carsnciais of a reference population. In normal individuals, hematocrit and hemoglobin levels vary in accordance with the phase of development of the individual, and as a function of hormonal stimulation, environmental oxygen pressure, age and gender 1.

The amount of iron in the body varies according to weight, gender, hemoglobin level and the size of body iron stores 2. Iron deficiency is defined by a reduction in ferritin levels that generally results from a diet in which the bioavailability of iron is inadequate or from an increased need for iron during a period of intense growth pregnancy, adolescence and infancy. Decreased ferritin levels may also be the consequence of extensive blood loss, either in hemorrhagic conditions or in cases of occult bleeding 3,4or following inflammatory processes caused by various chronic diseases.

Iron deficiency anemia is the most advanced stage of iron deficiency. It is characterized not only by low hemoglobin and hematocrit levels but also by a reduction or depletion of iron stores, by low serum iron levels and decreased transferrin saturation 5.

In general, serum iron levels decrease in the presence of acute and chronic infections, extensive inflammatory processes, malignant neoplasms, during menstruation and, principally, when there is a prolonged deficit of iron in the diet.

Iron is known to play an important role in the formation of hemoglobin, myoglobin and other heme proteins. In the diet, iron is present in red meat, eggs, vegetables and grains. Its absorption depends largely on its balance in the body.

Infants and children, particularly schoolchildren, need iron-rich diets for their growth, psychomotor development and intellectual capacity 6. Evidence that iron deficiency hampers psychomotor development and cognitive function is attracting more and more interest. Anemia is more common in infants, in children of 3 to 6 years of age and in adolescents of 11 to 17 years of age 10,11particularly those living in developing countries, constituting a serious public health issue 3.

The World Health Organization estimates that around two billion individuals worldwide, i. In developed countries, 4. Notwithstanding, few data are currently available on the prevalence of iron deficiency anemia in adolescents.

Revisión Iron deficiency anemia in adolescents ; a literature review

In boys, these rates are lower A study conducted in Switzerland with teenagers showed a prevalence of anemia of In other European countries such as Spain, Sweden and England, the prevalence of anemia in adolescents has been reported to be around 4. In developing countries, the situation is more serious. Population-based studies in which the prevalence of anemia is compared in urban and rural areas show that the percentage of individuals with anemia is much higher in rural areas.


Adolescence is an important period of nutritional vulnerability due to the increased nutritional demands for growth and development during this phase.

Anemia por deficiencia de hierro en adolescentes: una revision de la literatura

Iron requirement is high because of intense growth and muscle development, resulting in an increase in blood volume In adolescents, dietary iron intake may be poor as the result of inadequate intake at this particular time of life or the adolescent’s diet may have been iron-poor since infancy; however, it is vital that there is an adequate level of iron in the diet with sufficient bioavailability to satisfy the body’s demands during this particular time of life Another characteristic that is common among adolescents refers to a change in dietary habits resulting from peer influence, a need for self-affirmation within the family or as the result of the behavioral or social changes that teenagers face during this phase In this context, food also serves as a vehicle that is used to demonstrate feelings of rebelliousness and dissatisfaction, particularly in families in which dialogue is lacking.

In adolescence, eating disorders may include a refusal to eat, excessive weight-loss diets and skipping meals, all because of the undue importance given to body image as a result of inappropriate advertising in the media and the cult of ultrathin, often malnourished models. Another important aspect that should be taken into consideration refers to the consequences of current lifestyles, with increasing dependence on food that can be prepared rapidly and simply.

Fast food is potentially harmful, since there are often important nutritional limitations with this type of food, including its high energy, fat and sodium content in conjunction with its poor fiber, vitamin, calcium and iron content Consequently, adolescents’ diets are often based on inadequate socioeconomic and sociocultural values, a distorted body image, poor family eating habits, the financial situation of the family, food consumed outside the home, the availability, ease and speed of food preparation and the influence of peers and of the media.

Most of these factors contribute to an iron-poor diet. Iron deficiency anemia is the result of a protracted imbalance between iron intake and demand A great number of factors that predispose to iron deficiency have been mentioned in the literature, particularly early discontinuation of exclusive breastfeeding, lack of iron-rich foods in the diet, frequent tea consumption, prematurity, low birthweight, intrauterine growth restriction, twin pregnancies, perinatal bleeding, socioeconomic level, poor maternal schooling and poor basic sanitation and life conditions 2,11,27, The most important factors determinin iron deficiency anemia.

An inadequate diet, with poor iron, micronutrient and vitamin content, leading to an insufficient intake of nutrients such as iron, folic acid, vitamin A, vitamin B12 and vitamin D Multiple micronutrient deficiencies are still common worldwide and may be present at any age, hampering both physical and cognitive development The use of medication and food that inhibit iron absorption, including antacids, aspirin, nonsteroidal anti-inflammatory drugs, and excessive phytate, phosphate, oxalate and tannin in-take Furthermore, overweight and obesity lead to a continuous inflammatory process, intensifying anemia and hampering treatment In this context, these patients also have flattening or atrophy of the intestinal villi, hampering micronutrient absorption 34, Another group that merits particular attention consists of adolescent athletes in whom the prevalence of iron deficiency ranges from 5 to 7.

In addition, they are predisposed to developing “sports anemia”. This type of anemia appears to be associated with various factors including dilutional pseudoanemia, mechanical intravascular hemolysis and iron loss 22,36, Iron deficiency caused by blood loss resulting from injury, accidents or blood donation every ml of blood donated per year results in the loss of another 0.

Iron loss due to parasitosis of the gastrointestinal tract Entamoeba histolytica, Necator americanusAscaris lumbricoidesSchistosoma mansoni, Trichuris trichiura 38esophagitis, angiodysplasia, telangiectasia, atrophic gastritis, colitis, Helicobacter pylori infection, coeliac disease 39,40inflammatory bowel disease, diverticulosis, hemorrhoids, gastrectomy or gastroplasty bariatric surgeryetc.

Genitourinary iron loss of various etiologies 46including paroxysmal nocturnal hemoglobinuria and glomerulonephritis. Pregnancy, childbirth and the use cardnciais intrauterine devices. Menarche and menstrual abnormalities in adolescents, in combination with an inadequate diet.

Heavy menstrual bleeding is also a common cause of iron deficiency and iron deficiency anemia in women of reproductive age. In these cases, menstrual bleeding is moderate, but chronically heavier than normal, causing a negative iron balance 47, Iron deficiency anemia is less common in adolescent boys than in girls and this is carenciaia by the physiological increase in hemoglobin levels caused by sexual maturation.

Nonetheless, iron deficiency may be higher in this age group due to blood volume expansion and the increase in muscle mass On the other hand, any increase in hemoglobin levels that might be expected in girls is offset by menstrual blood loss 49, Other factors that may increase the risk of anemia and iron deficiency in girls include use of the intrauterine device, pregnancy and also childbirth 29, The association between infection and anemia remains controversial; however, the reduction anmeias hemoglobin levels during an infectious process is presumed to be the result of impaired iron release from the reticuloendothelial system and a consequent reduction in the amount of iron available for anemkas Table II lists the most important factors responsible for iron deficiency anemia in adolescents.


The influence of hormones as a cause of anemia in adolescence. Androgens stimulate erythropoietin action by increasing or facilitating its production in the erythroid stem cells. Anemas, estrogens inhibit the effects of erythropoietin Due to changes in the nutritional requirements of adolescents -at menarche in girls and as a result of the hormonal changes at puberty in boys- hemoglobin levels differ as a function of gender, age or stage of sexual maturity 12,53 table I.

In women of reproductive ahemias, menstrual bleeding defines anemia, sometimes requiring daily oral iron supplementation. Women in whom menstrual bleeding is excessive, either with respect to the number of bleeding days or to the amount of flow and the occurrence of menstrual clots, need to be monitored continuously for as long as dysfunctional uterine bleeding is pre-sent 47,54a period in which iron anejias may indeed be required.

The most important protein as far as iron reserves are concerned is ferritin, which is found in almost all the cells of the body, iron reserves being situated principally in organs such as the spleen, liver and bone marrow 33, Serum ferritin level is the anemoas accurate indicator of body iron stores Plasma ferritin levels decrease when there is a deficiency of iron that is not complicated by another concomitant disease.

This reduction in ferritin occurs early, well before the abnormalities in hemoglobin levels, serum iron levels or in erythrocyte size become apparent. On the other hand, increased ferritin levels may anejias in the presence of infections, neoplasms in general, and in cases of carnciais, lymphoma, breast cancer, renal disease, rheumatoid arthritis, hemochromatosis or carenciaix, as well as following alcohol consumption Serum ferritin, when used alone anemiass a single parameter, is not considered a good indicator of the nutritional iron status of a population, since this measurement does not provide all the information necessary on the prevalence of anemia 27, To reach a definitive diagnosis of iron deficiency anemia, in addition to performing a full blood count hemoglobin, aneemias, red blood cell countferritin and serum iron levels should be measured 27, Iron is essential for most living creatures, since it plays a role in numerous vital processes ranging from cell oxidative mechanisms to oxygen transport to the tissues.

Iron homeostasis is regulated principally by iron absorption rather than excretion; therefore, serum iron level reflects the balance between the amount of iron absorbed and the amount used cadenciais the body 33, Iron deficiency develops gradually and progressively until anemia is established 37,39 table III. The first stage of anemia consists of iron depletion or a negative iron balance. It is characterized by a period of greater vulnerability affecting iron stores and may progress slowly to a more severe deficiency, with functional consequences.

The second stage, also referred to as “iron deficiency”, is characterized by a phase of erythropoiesis.

Iron is depleted, but anemia is not yet present, although biochemical abnormalities reflect its inability to produce hemoglobin normally.

The third stage iron deficiency anemia itself is characterized by a reduction in iron delivery to the bone marrow, reducing both hemoglobin synthesis and content in erythrocyte precursor cells. The damage inflicted on the body increases as the concentration of available iron diminishes 2, To diagnose iron deficiency anemia, a full blood count must be performed and serum ferritin levels must be measured 37 38 60 When carfnciais is deficient, the body initially turns to anrmias iron stores, consequently depleting them.

It is at this stage that ferritin levels fall; however, there are no functional abnormalities at this point. Next, serum iron levels decrease, transferrin saturation diminishes and iron-binding capacity increases; however, anemia is not yet present.

It is only when the negative iron balance persists that anemia develops or manifests it-self 29, Diagnosis is based on three different aspects: In the majority of cases, the onset of anemia is insidious, with symptoms appearing gradually.


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