Anemia (literally, “a lack of blood”) is defined by the World Health Organization as a hemoglobin level less than 12 gm/dL in women and less than 13 gm/dL in men. On the basis of these criteria, the prevalence of anemia in the elderly ranges from 8 to 44 percent. (Smith D. Anemia in the elderly. Am Fam Phys. 2000;62[7]:1565-72)
In contrast to younger individuals—who usually complain of shortness of breath, weakness, fatigue, dizziness, or poor exercise tolerance when they become anemic—the elderly often just reduce their activities and expectations as anemia progresses. The insidious onset of anemia may make it seem as if an older person is suffering from normal decline.
Therefore, even physicians may overlook anemia when they mistakenly assume that its manifestations are simply due to the aging process.
Once anemia is discovered, an underlying cause can be determined in the majority of elderly persons.
What Causes Anemia in Elderly People?
The causes of anemia are sometimes relatively straightforward: a person who has recently lost a significant amount of blood (e.g., surgery or trauma) is likely to be anemic for several weeks until new blood cells are produced—or until a transfusion is administered.
At other times, the underlying cause of anemia is only determined when a serendipitous discovery of a low hemoglobin level leads to a thorough medical evaluation.
The causes of anemia in the elderly (and their prevalence) include:
- Anemia of chronic disease (30 – 45%): associated with diabetes, rheumatoid arthritis or other autoimmune conditions, renal insufficiency (kidney failure), chronic infections (tuberculosis, hepatitis, etc.), cancer, osteoarthritis, or malnutrition.
- Iron deficiency (15 – 30%): most commonly due to ongoing blood loss from the GI tract caused by aspirin or other nonsteroidal anti-inflammatories, ulcers, colon cancer, or diverticulosis. Other causes of blood loss—or iron deficiency due to poor nutrition—are less likely.
- Post-hemorrhagic (5 – 10%): surgery or trauma leads to acute blood loss; anemia develops within hours to days as fluid shifts from tissue spaces into blood vessels and dilutes the intravascular blood. If body stores of iron are adequate (iron supplements are commonly recommended, as well) the anemia will correct over the ensuing six to eight weeks.
- Vitamin B12 and folate deficiency (5 – 10%): B12 deficiency is the cause of “pernicious” anemia, characterized by abnormally large red blood cells and a spectrum of neurologic disorders. Classically, the vitamin deficiency is caused by autoimmune damage to parietal cells in the stomach—cells that normally secrete an intrinsic factor that assists in the absorption of B12. Anemias caused by B12 or folate deficiency share certain characteristics, and it is important to distinguish between the two…or treat for both simultaneously.
- Chronic leukemia or lymphoma (~5%): precursor cells in the bone marrow that normally replace red blood cells can be replaced, or “crowded out,” by malignant white blood cells.
- Myelodysplastic syndrome (~5%): the precursors that normally manufacture red cells and/or white cells in the marrow mutate and grow abnormally. This leads to ineffective production of normal red blood cells and a resultant anemia. Myelodysplastic syndrome frequently converts to acute leukemia.
- No known cause (15 – 25%)
(From Joosten E, et al. Prevalence and causes of anaemia in a geriatric hospitalized population. Gerontology 1992;38:111-17)
Rather than being a result of the normal aging process, anemia in an elderly individual is usually due to an underlying disease process. Correction of the causative condition and treatment of the anemia often improves the person’s quality of life and, possibly, longevity.
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