Official websites use. Share sensitive information only on official, secure websites. Address for correspondence: Camila M. Chaparro, Independent Consultant, International Nutrition. We outline definitions and classifications of anemia, describe the biological mechanisms through which anemia develops, and review the variety of conditions that contribute to anemia development. Accumulating evidence indicates that the proportion of anemia due to ID differs by population group, geographical setting, infectious disease burden, and the prevalence of other anemia causes.
Further research is needed to explore the role of additional nutritional deficiencies, the contribution of infectious and chronic disease, as well as the importance of genetic hemoglobin disorders in certain populations. Keywords: anemia, iron deficiency anemia, nutritional anemias, anemia of inflammation. Establishing appropriate Hb thresholds to define anemia is essential for ensuring that anemia is correctly identified, and its negative effects prevented.
As important, understanding the diverse and complex etiology of anemia is crucial for developing appropriate interventions that address the context-specific causes of anemia and for monitoring the success of anemia control programs. To that end, the primary aims of this paper are to outline definitions and classifications of anemia; describe the biological mechanisms through which anemia develops; review the variety of factors and conditions that contribute to anemia development, emphasizing those most prevalent in low- and middle-income countries LMICs ; and identify research needs.
Although our primary focus is on anemia and its etiology at a population level, the information we present on definitions and classifications of anemia, as well as its etiology, is relevant to individual-level assessment by clinicians. We reviewed the peer-reviewed literature on definitions and classifications of anemia, global magnitude and epidemiology of anemia, and causes of anemia, including their biological mechanisms and public health significance.
We also consulted gray literature, particularly documents relevant to defining anemia and nutritional status published by international organizations. Anemia is alternately defined as a reduced absolute number of circulating RBCs 12 or a condition in which the number of RBCs and subsequently their oxygen-carrying capacity is insufficient to meet physiologic needs.
