Iron Deficiency Anemia - Cause

Cause

A diagnosis of iron-deficiency anemia then requires further investigation as to its cause. It can be caused by increased iron demand or decreased iron intake, and can occur in both children and adults.

• Blood loss.

Blood contains iron within red blood cells. So if a person loses blood, he or she will lose some iron. Women with heavy periods are at risk of iron deficiency anemia because they lose blood during menstruation. Slow, chronic blood loss within the body — such as from a peptic ulcer, a hiatal hernia, a colon polyp or colorectal cancer — can cause iron-deficiency anemia. Gastrointestinal bleeding can result from regular use of some over-the-counter pain relievers, especially aspirin.

• A lack of iron in the diet.

The body regularly gets iron from the foods eaten. If a person consumes too little iron, over time the body can become iron-deficient. Examples of iron-rich foods include meat, eggs, leafy green vegetables and iron-fortified foods. For proper growth and development, infants and children need iron from their diet, too.

• An inability to absorb iron.

Iron from food is absorbed into the bloodstream in the small intestine. An intestinal disorder, such as celiac disease, which affects the intestine's ability to absorb nutrients from digested food, can lead to iron-deficiency anemia. If part of the small intestine has been bypassed or removed surgically, that may affect the ability to absorb iron and other nutrients.

• Pregnancy.

Without iron supplementation, iron deficiency anemia occurs in many pregnant women because their iron stores need to serve their own increased blood volume as well as be a source of hemoglobin for the growing fetus.

The leading cause of iron deficiency worldwide is infestation with parasitic worms (hookworms, whipworms, roundworms). Estimates of infection in the world population vary from a minimum of a billion humans to as many as 5 or 6 billion. In addition to parasitosis, dietary insufficiency, malabsorption, chronic blood loss, diversion of iron to fetal erythropoiesis during pregnancy, intravascular hemolysis and hemoglobinuria or other forms of chronic blood loss should all be considered, according to the patient's sex, age, and history. Other common causes include gastrointestinal blood loss due to drug therapy (often in the case of NSAIDs or aspirin), and hypochlorhydria/achlorhydria (often due to long-term proton pump inhibitor therapy). In babies and adolescents, rapid growth may outpace dietary intake of iron, and result in deficiency without disease or grossly abnormal diet. In women of childbearing age, heavy or long menstrual periods can also cause mild iron-deficiency anemia.

Especially in adults over the age of 50, iron deficiency is often a sign of other disease in the gastrointestinal tract, such as chronic bleeding from any cause (for example, a colon cancer) that causes loss of blood in the stool. Such loss is often undetectable, except with special testing. In adults, 60% of patients with iron-deficiency anemia have underlying gastrointestinal disorders leading to chronic blood loss, and this percentage increases with patient age. Iron deficiency in adult men from purely dietary causes is quite rare, and in such cases other causes of iron loss must be vigorously sought until found.