Iron deficiency anaemia (IDA) is the most common form of anaemia. Causes include:

• decreased iron intake (dietry)
• increased iron loss (e.g. slow bleeding from colon Ca)
  • IDA is caused by GI bleed until proven otherwise
• increased iron requirements (e.g. in pregnancy)
• Inadequate iron absorption
  • Mainly absorbed in duodenum/jejunum, requires stomach acid to keep iron in soluble ferrous Fe2 form.
  • Without acid it changes to the insoluble Fe3 form
  • Medications that reduce the stomach acid (PPI) can affect iron absorption
  • Conditions affecting duodenum/jejunum (caeliac, crohns) can also cause inadequate iron absorption

In adults the most common cause is blood loss

In children the most common cause is diet

Risk factors:

• Pregnancy - Increased demand
• Vegetarian diet - Takes 4 yrs to become iron deficient due to diet
• Menorrhagia
• Hookworm infestation
• CKD
• Coeliac disease
• Gastrectomy
• NSAID use
• Chronic heart failure