Defisiensi Besi pada Anak Muda di Negara Berpenghasilan Rendah dan Pendekatan Baru untuk Ini adalah Pencegahan (SHALLY MARLI MAULANA)
Iron Deficiency in Young Children in Low-Income Countries and New Approaches for Its Prevention 1,2
Chessa K. Lutter*
Pan American Health Organization, Washington, DC 20037
Introduction
Anemia resulting from severe iron deficiency (ID)3 is the most prevalent and widespread nutrition problem in infants and young children in the developing world (1) and has proven very resistant to prevention through public health interventions. Accumulated evidence from animal and human studies suggests that such deficiencies are associated with adverse effects on child cognitive and motor development (2–4). Therefore, effective interventions to improve iron status will likely have important health benefits.
Action to reduce young child ID would benefit from overarching policy and programmatic guidance that informs decision makers about appropriate intervention(s) or what to do, when to do it, and also addresses appropriate delivery models or howto do it.Most policies do not consider the role of maternal iron status or birth practices in the etiology of ID; supplementation for pregnant women is recommended for maternal health and not as a broader strategy to also improve newborn iron status. Interventions that could protect iron status at birth and during the first 6 mo of life, such as delayed umbilical cord clamping (5) and promotion of exclusive breast-feeding are rarely considered. In some settings, deworming is also a useful intervention to consider (6). The opportunities for different and mutually reinforcing interventions to prevent ID in young children need to be harnessed.
In this introductory article, I discuss how ID and iron deficiency anemia (IDA) are defined and present anemia prevalence and trend data. I also summarize how new approaches to prevent ID in young children reflect a number of factors, including the recognition of the multiple opportunities where intervention is possible and the development of new vehicles to deliver iron. I close with a description of why attention to delivery systems and monitoring and evaluation is so important and a success story to illustrate how the prevalence of young child anemia can be greatly reduced.
Anemia resulting from severe iron deficiency (ID)3 is the most prevalent and widespread nutrition problem in infants and young children in the developing world (1) and has proven very resistant to prevention through public health interventions. Accumulated evidence from animal and human studies suggests that such deficiencies are associated with adverse effects on child cognitive and motor development (2–4). Therefore, effective interventions to improve iron status will likely have important health benefits.
Action to reduce young child ID would benefit from overarching policy and programmatic guidance that informs decision makers about appropriate intervention(s) or what to do, when to do it, and also addresses appropriate delivery models or howto do it.Most policies do not consider the role of maternal iron status or birth practices in the etiology of ID; supplementation for pregnant women is recommended for maternal health and not as a broader strategy to also improve newborn iron status. Interventions that could protect iron status at birth and during the first 6 mo of life, such as delayed umbilical cord clamping (5) and promotion of exclusive breast-feeding are rarely considered. In some settings, deworming is also a useful intervention to consider (6). The opportunities for different and mutually reinforcing interventions to prevent ID in young children need to be harnessed.
In this introductory article, I discuss how ID and iron deficiency anemia (IDA) are defined and present anemia prevalence and trend data. I also summarize how new approaches to prevent ID in young children reflect a number of factors, including the recognition of the multiple opportunities where intervention is possible and the development of new vehicles to deliver iron. I close with a description of why attention to delivery systems and monitoring and evaluation is so important and a success story to illustrate how the prevalence of young child anemia can be greatly reduced.
Diagnosis, prevalence, and trends
WHO estimates that half of all anemias are caused by ID and that the prevalence of ID in developing countries is ;2.5 times that of anemia (7). Anemia is defined as insufficient hemoglobin (Hb) or red blood cells. Additional causes include other nutritional deficiencies (vitamins B-12, B-6, and A, riboflavin, and folic acid), chronic disease and inflammation, conditions that cause blood loss or hemolysis (e.g., parasitic infections such as hookworm or malaria or hemorrhage) and hemoglobinopathies. Anemia caused by ID is referred to as IDA. Although there is disagreement about the appropriate cutoff values for the diagnosis of ID and IDA in infants (8,9), the commonly used indicators and values for diagnosis recommended by WHO are Hb ,110 g/L and serum ferritin ,10–12 mg/L for infants 6–12 mo of age (10). Alternative cutoff levels for insufficient Hb have been proposed as ,105 g/L for infants 4 and 6 mo and ,100 g/L for infants 9 mo of age (8). Other laboratory criteria for IDA include lowHbtogether with other indications of ID; these include low erythrocyte mean cell volume, low serum ferritin, high zinc protoporphyrin, and/or high soluble transferrin receptors. However, the cutoff values for these indicators are even less well developed than those for Hb and serum ferritin.
The prevalence of anemia is higher during infancy and early childhood than at any other time in the life cycle, including pregnancy (11). Among children ,5 y of age, the prevalence of anemia (defined as Hb ,110 g/L) ranges from ;35 to 90% in those countries where a Demographic and Health Survey conducted between 1996 and 2006 included Hb measurements (Table 1). Among infants, the prevalence ranges from 25 to nearly 100%, with the majority of countries in excess of 70%. Recent estimates put the global prevalence of anemia in young children at 41.8% (12). Iron reserves of term, normal-birthweight infants, born to iron-replete mothers and who received delayed cord clamping at birth should be adequate to meet iron needs until 6 mo of age (13). However, the very high prevalence of anemia by this age indicates that infants are becoming anemic earlier than expected and that even more are likely to be ID but not yet anemic. Even if prevalence estimates were revised to use the more conservative cutoff levels suggested above, anemia would still be the most prevalent nutritional problem (Fig. 1).
FIGURE 1 Prevalence of anemia by different cutoff values in children 6–9 mo of age in selected Latin American countries with recent nationally representative data; constructed from primary analysis of Demographic and Health Survey data for each country and year represented.
New approaches to prevention of ID Current guidelines for iron supplementation in young children
are based on the assumption that iron present at birth and in breast milk is sufficient to meet requirements for the first 6 mo of life. However, this assumption depends on a number of factors
not often present in low-income countries: adequate maternal iron status, adequate birth practices that promote the transfer of a portion of the birth iron via placental blood (5,14), and exclusive breast-feeding that avoids pathological iron loss via damage to the integrity of the intestinal wall. Breast milk contains little iron, but it is in a form that is highly bioavailable (13). Introducing other liquid or solid foods during the first 6 moof life can interfere with the absorption of the iron present in breast milk (15). Therefore, interventions to prevent ID in young children need to start early in their mother’s pregnancy (by supplementing her) and continue at birth (by delayed umbilical
cord clamping and promoting early initiation of breast-feeding).
After 6 mo, iron of adequate amount and bioavailability is necessary to prevent ID (16). Meeting iron requirements through food alone is nearly impossible, particularly between 6 and 12
mo of age, when requirements remain very high and infants consume relatively small amounts of food (17). It is during this period that universal supplementation is recommended, except in malaria-endemic areas (18). Until recently, many Ministries of Health in Latin America recommended daily supplementation with ferrous sulfate, which is highly efficacious in preventing
and treating ID. Unlike vitamin A deficiency, however, which can be prevented through twice-yearly high-dose supplements and distributed via immunization campaigns, prevention and treatment of ID require routine supplementation (usually daily or weekly). Therefore, it has traditionally been delivered through routine, often weak, health services.
Strategies to prevent early childhood ID need to include interventions beyond the typical one of starting medicinal iron supplements at 6 mo (2 mo for low-birthweight infants), taking advantage of the full range of interventions and contact with mother-infant pairs. Its prevention requires policy and programmatic guidance that informs decision makers about what to do, when to do it, and also addresses appropriate delivery models or how to do it. It also requires addressing the multiple opportunities available for prevention; pregnancy, at birth, the immediate postnatal period, and during the first 24 mo of life, as illustrated in Table 2.
FIGURE 2 Trends in anemia (Hb ,110 g/L) in children 6–59 mo of age in selected countries with nationally representative trend data available; constructed from data presented in Table 1, except for Bolivia 2003, which was calculated from primary analysis of the Demographic and Health Survey for children ,36 mo to be consistent with the age range reported in 1998.
In conclusion, ID is themost prevalent and widespread nutrition problem in infants and young children in low-income countries, is associated with large adverse effects on cognitive development, and has been difficult to prevent through traditional public health approaches. Its prevention requires overarching policy and programmatic guidance that inform decision makers about what to do and when to do it and also address appropriate delivery models or how to do it. This also requires addressing the multiple opportunities
available for prevention: pregnancy, at birth, the immediate postnatal period, and during the first 24 mo of life. New vehicles to deliver iron as well as other micronutrients and in some cases macronutrients are efficacious in reducing anemia and appear to be more acceptable to mothers and children. However, to reduce national prevalances of anemia, the many challenges of delivery through the public health systems must be overcome.
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WHO estimates that half of all anemias are caused by ID and that the prevalence of ID in developing countries is ;2.5 times that of anemia (7). Anemia is defined as insufficient hemoglobin (Hb) or red blood cells. Additional causes include other nutritional deficiencies (vitamins B-12, B-6, and A, riboflavin, and folic acid), chronic disease and inflammation, conditions that cause blood loss or hemolysis (e.g., parasitic infections such as hookworm or malaria or hemorrhage) and hemoglobinopathies. Anemia caused by ID is referred to as IDA. Although there is disagreement about the appropriate cutoff values for the diagnosis of ID and IDA in infants (8,9), the commonly used indicators and values for diagnosis recommended by WHO are Hb ,110 g/L and serum ferritin ,10–12 mg/L for infants 6–12 mo of age (10). Alternative cutoff levels for insufficient Hb have been proposed as ,105 g/L for infants 4 and 6 mo and ,100 g/L for infants 9 mo of age (8). Other laboratory criteria for IDA include lowHbtogether with other indications of ID; these include low erythrocyte mean cell volume, low serum ferritin, high zinc protoporphyrin, and/or high soluble transferrin receptors. However, the cutoff values for these indicators are even less well developed than those for Hb and serum ferritin.
The prevalence of anemia is higher during infancy and early childhood than at any other time in the life cycle, including pregnancy (11). Among children ,5 y of age, the prevalence of anemia (defined as Hb ,110 g/L) ranges from ;35 to 90% in those countries where a Demographic and Health Survey conducted between 1996 and 2006 included Hb measurements (Table 1). Among infants, the prevalence ranges from 25 to nearly 100%, with the majority of countries in excess of 70%. Recent estimates put the global prevalence of anemia in young children at 41.8% (12). Iron reserves of term, normal-birthweight infants, born to iron-replete mothers and who received delayed cord clamping at birth should be adequate to meet iron needs until 6 mo of age (13). However, the very high prevalence of anemia by this age indicates that infants are becoming anemic earlier than expected and that even more are likely to be ID but not yet anemic. Even if prevalence estimates were revised to use the more conservative cutoff levels suggested above, anemia would still be the most prevalent nutritional problem (Fig. 1).
FIGURE 1 Prevalence of anemia by different cutoff values in children 6–9 mo of age in selected Latin American countries with recent nationally representative data; constructed from primary analysis of Demographic and Health Survey data for each country and year represented.
New approaches to prevention of ID Current guidelines for iron supplementation in young children
are based on the assumption that iron present at birth and in breast milk is sufficient to meet requirements for the first 6 mo of life. However, this assumption depends on a number of factors
not often present in low-income countries: adequate maternal iron status, adequate birth practices that promote the transfer of a portion of the birth iron via placental blood (5,14), and exclusive breast-feeding that avoids pathological iron loss via damage to the integrity of the intestinal wall. Breast milk contains little iron, but it is in a form that is highly bioavailable (13). Introducing other liquid or solid foods during the first 6 moof life can interfere with the absorption of the iron present in breast milk (15). Therefore, interventions to prevent ID in young children need to start early in their mother’s pregnancy (by supplementing her) and continue at birth (by delayed umbilical
cord clamping and promoting early initiation of breast-feeding).
After 6 mo, iron of adequate amount and bioavailability is necessary to prevent ID (16). Meeting iron requirements through food alone is nearly impossible, particularly between 6 and 12
mo of age, when requirements remain very high and infants consume relatively small amounts of food (17). It is during this period that universal supplementation is recommended, except in malaria-endemic areas (18). Until recently, many Ministries of Health in Latin America recommended daily supplementation with ferrous sulfate, which is highly efficacious in preventing
and treating ID. Unlike vitamin A deficiency, however, which can be prevented through twice-yearly high-dose supplements and distributed via immunization campaigns, prevention and treatment of ID require routine supplementation (usually daily or weekly). Therefore, it has traditionally been delivered through routine, often weak, health services.
Strategies to prevent early childhood ID need to include interventions beyond the typical one of starting medicinal iron supplements at 6 mo (2 mo for low-birthweight infants), taking advantage of the full range of interventions and contact with mother-infant pairs. Its prevention requires policy and programmatic guidance that informs decision makers about what to do, when to do it, and also addresses appropriate delivery models or how to do it. It also requires addressing the multiple opportunities available for prevention; pregnancy, at birth, the immediate postnatal period, and during the first 24 mo of life, as illustrated in Table 2.
FIGURE 2 Trends in anemia (Hb ,110 g/L) in children 6–59 mo of age in selected countries with nationally representative trend data available; constructed from data presented in Table 1, except for Bolivia 2003, which was calculated from primary analysis of the Demographic and Health Survey for children ,36 mo to be consistent with the age range reported in 1998.
In conclusion, ID is themost prevalent and widespread nutrition problem in infants and young children in low-income countries, is associated with large adverse effects on cognitive development, and has been difficult to prevent through traditional public health approaches. Its prevention requires overarching policy and programmatic guidance that inform decision makers about what to do and when to do it and also address appropriate delivery models or how to do it. This also requires addressing the multiple opportunities
available for prevention: pregnancy, at birth, the immediate postnatal period, and during the first 24 mo of life. New vehicles to deliver iron as well as other micronutrients and in some cases macronutrients are efficacious in reducing anemia and appear to be more acceptable to mothers and children. However, to reduce national prevalances of anemia, the many challenges of delivery through the public health systems must be overcome.
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