Anemia

Lore & Background

Anemia can be caused by blood loss, decreased red blood cell production, or increased red blood cell breakdown. Causes of blood loss include menstruation, bleeding from inflammation of the stomach or intestines, surgery, serious injury, or blood donation. Decreased production can result from iron deficiency, folate deficiency, vitamin B12 deficiency, thalassemia, or bone marrow tumors. Increased breakdown may stem from genetic disorders like sickle cell anemia, infections such as malaria, or autoimmune diseases like autoimmune hemolytic anemia.

Reader's Guide

Anemia is classified by red blood cell size: microcytic (small cells), macrocytic (large cells), or normocytic (normal size). Symptoms vary with onset; chronic anemia may cause tiredness, weakness, shortness of breath, headaches, and reduced exercise ability, while acute anemia can lead to confusion, fainting, loss of consciousness, and increased thirst. Diagnosis is based on hemoglobin levels, with further testing to determine the underlying cause. Treatment depends on the specific cause; iron pills may be used for prevention in certain groups like pregnant women, but dietary supplementation without determining the cause is not recommended. Blood transfusions are typically based on symptoms, and erythropoiesis-stimulating agents are reserved for severe cases. Anemia is a global health target, included in the WHO's six nutrition targets for 2025 and linked to Sustainable Development Goal 2 for zero hunger.

Did You Know?

• Anemia is the most common blood disorder, affecting about a fifth to a third of the global population.
• Iron-deficiency anemia is the most common cause worldwide, affecting nearly one billion people.
• In 2025, the WHO noted a 35.5% anemia rate in pregnant women, compared to 30.5% in non-pregnant women.
• The name derives from Ancient Greek 'an-' (not) and 'haîma' (blood).