Anemia - Risk Factors

Causes

Iron Deficiency Anemia

Iron deficiency anemia occurs when the body lacks mineral iron to produce the hemoglobin it needs to make red blood cells. In general, there are three stages leading from iron deficiency to anemia:

• First, there is an insufficient supply of iron, which causes iron stores in the bone marrow to be depleted. This stage generally has no symptoms.
• Second, iron deficiencies develop and begin to affect hemoglobin production. (Tests will show low hemoglobin and hematocrit levels.)
• Hemoglobin production declines to the point where anemia develops.

Most of the iron used in the body can be recycled from blood and reused. Nevertheless, iron deficiency can occur from a number of conditions.

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Inadequate Iron Intake. A healthy diet easily provides enough iron. In general, most people need just 1 mg, and menstruating women need 2 mg, of extra iron each day. This means that lack of iron in the diet is not a common cause of iron deficiency anemia, except in infants. In fact, most American adults may be consuming too much iron in their diet. Iron-poor diets are a cause of anemia only in people with existing risks for iron deficiency. Children who have not yet eaten iron-fortified formulas or iron-enriched cereal may also become anemic.

Blood Loss. Iron deficiencies most commonly occur from internal blood loss due to other conditions that vary in severity. These conditions include:

• Very heavy periods (menorrhagia), the most common causes of anemia in menstruating women
• Peptic ulcers, which may be caused by H. pylori infections, or use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen, and naproxen.
• Chronic gastritis, caused by long-term use of NSAIDs, although it is rarely significant enough to cause anemia.
• Duodenal ulcers
• Hemorrhoids, though rare
• Colon polyps
• Colon, stomach, and esophageal cancer
• Bleeding from esophageal varices, often present in alcoholics

Impaired Absorption of Iron. Impaired absorption of iron is caused by:

• Certain intestinal diseases (inflammatory bowel disease, celiac disease)
• Surgical procedures, particularly those involving removal of parts of the stomach and small intestine, can impair the ability of the stomach or intestine to absorb iron. (Such conditions also often impair vitamin B12 absorption.)
• Pica, the craving for non-food substances such as ice, starch, or clay, is a possible cause of iron deficiency in young children. To complicate matters, pica (particularly ice cravings) may also be a symptom, rather than a cause, of anemia.
• Certain intestinal infections, such as hookworm and other parasites.