Iron deficiency

State of diminished total body iron stores, characterized by reduced ferritin and transferrin saturation, leading to impaired erythropoiesis, iron-deficiency anemia, and disruption of other iron-dependent physiological functions.

Causes

• Blood loss

  • Menstrual blood loss

  • Gastrointestinal bleeding

  • Aspirin use

  • NSAID-related gastrointestinal injury

  • Frequent blood donation

  • Chronic occult bleeding from gastrointestinal tumors or polyps

• Malabsorption causes

  • Celiac disease

  • Gastric bypass surgery

  • Inflammatory bowel disease

  • Atrophic gastritis

  • Other disorders impairing iron absorption

• Inadequate dietary intake

  • Low iron intake

  • Vegan or vegetarian diet without adequate iron sources

  • Malnutrition

  • Poor dietary diversity

• Increased physiological requirements

  • Pregnancy

  • Growth spurts in children and adolescents

  • Increased demand during periods of rapid tissue expansion

• Other causes

  • Chronic inflammation affecting iron metabolism

  • Repeated blood sampling in hospitalized patients

  • Endurance exercise–related iron loss

  • Parasitic infections causing chronic blood loss

  • Genetic disorders affecting iron absorption or utilization