Accelerating action to reduce anemia: Review of causes and risk factors and related data needs

Abstract

Anemia is a major public health concern. Young children, menstruating adolescent girls and women, and pregnant women are among the most vulnerable. Anemia is the consequence of a wide range of causes, including biological, socioeconomic, and ecological risk factors. Primary causes include: iron deficiency; inherited red blood cell disorders; infections, such as soil-transmitted helminthiasis, schistosomiasis, and malaria; gynecological and obstetric conditions; and other chronic diseases that lead to blood loss, decreased erythropoiesis, or destruction of erythrocytes. The most vulnerable population groups in low- and middle-income countries are often at the greatest risk to suffer from several of these causes simultaneously as low socioeconomic status is linked with an increased risk of anemia through multiple pathways. Targeted and effective action is needed to prevent anemia. Understanding the causes and risk factors of anemia for different population subgroups within a country guides the design and implementation of effective strategies to prevent and treat anemia. A coordinated approach across various expert groups and programs could make the best use of existing data or could help to determine when newer and more relevant data may need to be collected, especially in countries with a high anemia burden and limited information on the etiology of anemia.

Keywords: anemia; anemia of inflammation; iron deficiency anemia; non-nutritional anemia; nutritional anemia.

FIGURE 1

Conceptual framework of anemia etiology. Notes: ^aHigh nutrient requirement due to growth, pregnancy, and increased susceptibility to infections during childhood and pregnancy. ^bEarly onset of childbearing, high parity, and short birth spacing. ^cInherited red blood cell disorders include sickle cell disorders, thalassemias, glucose-6-phosphate dehydrogenase (G6PD) deficiency, and other hemoglobinopathies. Source: Adapted and reproduced with permission from the publisher of reference. The original figure by Chaparro and Suchdev was developed based on determinants presented in references , , and .

FIGURE 2

Venn diagrams illustrating the weighted prevalence of iron deficiency, anemia, iron-deficiency anemia, and the proportions of anemic women with iron deficiency in nonpregnant women of reproductive age by category of infection burden: results from the BRINDA project. Results from the BRINDA Project include nationally representative surveys. Iron deficiency was defined as an inflammation-adjusted ferritin concentration <15 μg/L. Anemia was defined as a hemoglobin concentration <120 g/L. Iron-deficiency anemia was defined as a hemoglobin concentration <120 g/L and inflammation-adjusted ferritin concentration <15 μg/L. Countries were categorized by infection burden as follows—low: Georgia and the United States; moderate: Colombia and Mexico (2006 and 2012); and high: Cameroon, Côte d’Ivoire, Liberia, and Laos. Abbreviation: WRA, women of reproductive age. Source: Wirth et al.