Anemia is a condition characterized by a shortage of healthy red blood cells, which are vital for transporting oxygen throughout the body. Although sometimes considered a normal part of aging, anemia is often a sign of an underlying medical condition and should always be evaluated by a healthcare provider. Its prevalence significantly increases with age, affecting as many as 17% of individuals over 65 and an even higher percentage of those in nursing homes or hospitals. The reasons behind this increased susceptibility are varied and often multifactorial.
The primary causes of anemia in older adults
Studies show that the causes of anemia in older adults can be broadly divided into three main categories, each accounting for roughly one-third of all cases.
1. Anemia of chronic disease (ACD)
Anemia of chronic disease (ACD), also known as anemia of inflammation, is the most common type of anemia in older adults. It is not a disease in itself but a complication of other long-term medical conditions that involve inflammation, such as:
- Chronic kidney disease (CKD)
- Congestive heart failure
- Autoimmune diseases, like rheumatoid arthritis and lupus
- Cancer
- Chronic infections
In ACD, the body's inflammatory response interferes with red blood cell production in the bone marrow and affects how the body uses iron, even if iron stores are adequate. The resulting anemia is typically mild to moderate.
2. Iron deficiency anemia
Iron deficiency is the second most common cause of anemia in older adults. Unlike younger populations where poor dietary intake is a primary factor, in older adults, it is most often caused by chronic blood loss. This blood loss can be subtle and internal, originating from the gastrointestinal tract due to conditions such as:
- Ulcers or gastritis caused by nonsteroidal anti-inflammatory drugs (NSAIDs)
- Colon cancer or polyps
- Angiodysplasia (abnormal blood vessels)
- Diverticulosis
Other causes can include poor iron absorption due to certain surgeries, H. pylori infections, or reduced dietary intake.
3. Unexplained anemia of aging (UAA)
In a significant number of cases—up to one-third—the cause of anemia in older adults remains unexplained, even after a thorough diagnostic workup. This is often classified as Unexplained Anemia of Aging (UAA). It is believed to result from a combination of age-related changes, including a decline in hematopoietic stem cell function, lower testosterone levels, and low-grade inflammation.
Symptoms and diagnosis
Symptoms of anemia can be insidious and easily mistaken for normal signs of aging, which is why a medical evaluation is crucial. Common symptoms include:
- Fatigue and weakness
- Shortness of breath, especially during exertion
- Pale skin or pale gums/conjunctiva
- Dizziness
- Rapid or irregular heartbeat
- Headaches
Diagnosis starts with a complete blood count (CBC) to measure hemoglobin and hematocrit levels. Further tests are then used to pinpoint the cause:
- Serum ferritin levels: Measure the body's stored iron. It is a key test to differentiate iron deficiency anemia from ACD.
- Vitamin B12 and folate levels: To check for nutritional deficiencies, which are common and treatable.
- Blood smear and reticulocyte count: Examine red blood cell morphology and determine if the bone marrow is producing enough new red blood cells.
- Evaluation of underlying disease: Tests for kidney function, inflammation, or a bone marrow biopsy may be necessary depending on the suspected cause.
Comparison of common anemias in older adults
| Feature | Anemia of Chronic Disease (ACD) | Iron Deficiency Anemia (IDA) |
|---|---|---|
| Underlying Cause | Chronic inflammatory conditions (e.g., CKD, RA, cancer, infections) | Chronic blood loss (usually GI), poor diet, or malabsorption |
| Iron Status | High or normal iron stores, but iron is sequestered and unavailable for red blood cell production | Low iron stores and low iron availability for red blood cell production |
| Mean Corpuscular Volume (MCV) | Most commonly normocytic (normal cell size) but can be microcytic | Typically microcytic (small cell size), but can be normocytic in older adults |
| Ferritin Levels | Normal or high, as ferritin is an inflammatory marker | Low, indicating depleted iron stores |
| Treatment Focus | Addressing the underlying chronic condition and, in some cases, using erythropoietin-stimulating agents | Iron supplementation (oral or intravenous) and finding/treating the source of blood loss |
Treatment and management
Treatment for anemia in older adults is highly dependent on the cause.
- Address the underlying cause: The most critical step is to identify and treat the underlying condition. For ACD, this means managing the chronic inflammatory or infectious disease. For IDA, it involves investigating the source of blood loss, often requiring an endoscopic examination.
- Iron supplementation: For IDA, iron supplements are prescribed. In some cases, a lower dose is recommended to minimize gastrointestinal side effects. Intravenous iron is an option for patients who cannot tolerate or do not respond to oral supplements.
- Vitamin supplementation: For nutritional deficiencies, such as vitamin B12 or folate, supplements are effective. In cases of impaired absorption, parenteral (injected) vitamin B12 may be necessary.
- Erythropoietin-stimulating agents (ESAs): Medications that stimulate red blood cell production may be used for anemia related to chronic kidney disease or certain inflammatory conditions, especially if the body’s natural erythropoietin response is blunted.
- Blood transfusions: In severe cases, blood transfusions may be needed to quickly increase red blood cell counts.
Conclusion
While anemia is the most common blood disorder affecting older adults, it is not a normal part of aging. Instead, it is a significant medical concern with serious consequences, including increased risks of hospitalization, falls, cognitive impairment, and mortality. The underlying causes are often complex and multifactorial, frequently stemming from anemia of chronic disease, iron deficiency, or remaining unexplained. A thorough diagnostic process is essential to determine the specific cause and guide effective treatment, which can range from supplementation and managing underlying conditions to more advanced therapies. Given the potential for severe health outcomes, physicians should not dismiss even mild cases of anemia in this population. For more information on geriatric care, you can refer to the National Institute on Aging.
