Iron Deficiency

by CDC

Iron deficiency is the most common known form of nutritional deficiency. Its prevalence is highest among young children and women of childbearing age (particularly pregnant women). In children, iron deficiency causes developmental delays and behavioral disturbances, and in pregnant women, it increases the risk for a preterm delivery and delivering a low-birthweight baby. In the past three decades, increased iron intake among infants has resulted in a decline in childhood iron-deficiency anemia in the United States. As a consequence, the use of screening tests for anemia has become a less efficient means of detecting iron deficiency in some populations. For women of childbearing age, iron deficiency has remained prevalent.

To address the changing epidemiology of iron deficiency in the United States, CDC staff in consultation with experts developed new recommendations for use by primary health-care providers to prevent, detect, and treat iron deficiency. These recommendations update the 1989 "CDC Criteria for Anemia in Children and Childbearing-Aged Women" and are the first comprehensive CDC recommendations to prevent and control iron deficiency. CDC emphasizes sound iron nutrition for infants and young children, screening for anemia among women of childbearing age, and the importance of low-dose iron supplementation for pregnant women.

Introduction

In the human body, iron is present in all cells and has several vital functions - as a carrier of oxygen to the tissues from the lungs in the form of hemoglobin (Hb), as a facilitator of oxygen use and storage in the muscles as myoglobin, as a transport medium for electrons within the cells in the form of cytochromes, and as an integral part of enzyme reactions in various tissues. Too little iron can interfere with these vital functions and lead to morbidity and mortality.

In the United States, the prevalence of iron-deficiency anemia among children declined during the 1970s in association with increased iron intake during infancy. Because of this decline, the value of anemia as a predictor of iron deficiency has also declined, thus decreasing the effectiveness of routine anemia screening among children. In contrast, the rate of anemia among low-income women during pregnancy is high, and no improvement has been noted since the 1970s. These findings, plus increased knowledge about screening for iron status, raised questions about the necessity and effectiveness of existing U.S. programs to prevent and control iron deficiency. CDC requested the Institute of Medicine to convene an expert committee to develop recommendations for preventing, detecting, and treating iron-deficiency anemia among U.S. children and U.S. women of childbearing age. The committee met throughout 1992, and in 1993 the Institute of Medicine published the committee's recommendations. These guidelines are not practical for all primary health-care and public health settings, however, because they require serum ferritin testing during pregnancy. This testing may be appropriate in practices where women consistently visit their physician throughout pregnancy, but it is less feasible when analysis of serum ferritin concentration is unavailable or when prenatal care visits are sporadic. The CDC recommendations in this report - including those for pregnant women - were developed for practical use in primary health-care and public health settings.

Beside the Institute of Medicine, the American Academy of Pediatrics, the U.S. Preventive Services Task Force, the American College of Obstetricians and Gynecologists, the Federation of American Societies for Experimental Biology and the U.S. Public Health Service have all published guidelines within the past 9 years for health-care providers that address screening for and treatment of iron deficiency in the United States. Preventing and controlling iron deficiency are also addressed in Nutrition and Your Health: Dietary Guidelines for Americans.

The CDC recommendations differ from the guidelines published by the U.S. Preventive Services Task Force in two major areas. First, the Task Force recommended screening for anemia among infants at high risk for anemia and pregnant women only. The CDC recommends periodic screening for anemia among high-risk populations of infants and preschool children, among pregnant women, and among nonpregnant women of childbearing age. Second, the Task Force stated there is insufficient evidence to recommend for or against iron supplementation during pregnancy, but the CDC recommends universal iron supplementation to meet the iron requirements of pregnancy. The CDC recommendations for iron supplementation during pregnancy are similar to the guidelines issued by the American Academy of Pediatrics and the American College of Obstetricians and Gynecologists.

This report is intended to provide guidance to primary health-care providers and emphasizes the etiology and epidemiology of iron deficiency, the laboratory tests used to assess iron status, and the screening for and treatment of iron deficiency at all ages. The recommendations in this report are based on the 1993 Institute of Medicine guidelines; the conclusions of an expert panel convened by CDC in April 1994; and input from public health nutrition program personnel, primary health-care providers, and experts in hematology, biochemistry, and nutrition.

National health objective 2.10 for the year 2000 is to "reduce iron deficiency to less than 3% among children aged 1-4 and among women of childbearing age". The recommendations in this report for preventing and controlling iron deficiency are meant to move the nation toward this objective.

About the Author

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The Centers for Disease Control and Prevention (CDC) is one of the 13 major operating components of the Department of Health and Human Services (HHS), which is the principal agency in the United States government for protecting the health and safety of all Americans and for providing essential human services, especially for those people who are least able to help themselves.