Anaemia: Worldwide Prevalence and Progress in Reduction

Abstract

Anaemia---defined as a reduction in the circulating red blood cell mass such that oxygen-carrying capacity is insufficient to meet the body's physiological needs---is highly prevalent globally. The most common causes of anaemia include nutritional deficiencies, infections and genetic conditions that affect red cell production and/or survival. Iron deficiency has traditionally been thought to account for around half of anaemia cases. However, the proportion of anaemia attributable to iron deficiency appears to vary according to geographic region, demographics, anaemia severity and infection burden. Many conditions associated with anaemia are known to be more common among people in lower- and middle-income countries (LMICs), and particularly preschool children and women of reproductive age, meaning that anaemia affects these population groups disproportionately. In 2019, 1.76 billion people were affected by anaemia worldwide (prevalence of 23.67{\%}). The prevalence of anaemia in preschool children, pregnant women and non-pregnant women is considerably higher. Similarly, anaemia prevalence in the WHO regions of Africa and Southeast Asia was even higher than the global average among these three demographic groups. The Global Burden of Disease 2019 found that anaemia was responsible for 50.3 million years lived with disability (YLDs) representing 5.8{\%} of all YLDs. There are international targets and policy frameworks that aim to reduce the global burden of anaemia, many of which focus on micronutrient supplementation and fortification measures for women of reproductive age. Most countries are not presently on track to meet these anaemia control targets.