Anemia is defined by a lower-than-normal concentration of red blood cells or the oxygen-carrying protein, hemoglobin. This reduction impairs the blood’s ability to deliver sufficient oxygen to the body’s tissues, leading to symptoms like weakness and fatigue. In the United States, the prevalence of anemia in persons aged 65 and older is approximately 10-12% for those living in the community. This rate increases with age and comorbidity, reaching as high as 40% to 47% in hospitalized or nursing home residents. Anemia in older adults is not considered a normal part of aging but indicates an underlying health problem requiring investigation.
Anemia of Inflammation and Chronic Disease
Anemia of Inflammation and Chronic Disease (ACD) is the most frequent cause of anemia in the elderly population. Chronic conditions like infections, autoimmune disorders, cancer, and chronic heart failure trigger the sustained production of inflammatory cytokines. These cytokines interfere with the body’s iron metabolism and its ability to produce new red blood cells.
The inflammatory signals cause the liver to increase production of the hormone hepcidin, the body’s regulator of iron. Hepcidin blocks ferroportin, the protein that exports iron from storage cells and from cells lining the gut. This action locks iron away in storage sites, leading to low circulating iron available for red blood cell production, a state termed functional iron deficiency.
Even when total iron stores are adequate, hepcidin prevents the iron from being utilized by the bone marrow to synthesize hemoglobin. Furthermore, inflammatory cytokines suppress the bone marrow’s responsiveness to erythropoietin (EPO), the hormone that signals for red blood cell production. This mechanism—iron sequestration and suppressed bone marrow response—limits red blood cell creation.
Nutritional Deficiencies
A lack of specific raw materials needed for red blood cell production is a common cause of anemia in older adults, primarily involving iron, Vitamin B12, and folate. These deficiencies occur due to inadequate dietary intake or issues with nutrient absorption.
Iron deficiency anemia often results from decreased absorption in the elderly. Absorption issues arise because releasing iron from food requires sufficient stomach acid, which is often reduced in older individuals due to age or the use of acid-blocking medications.
Vitamin B12 deficiency is highly prevalent and can be caused by pernicious anemia, an autoimmune condition attacking stomach cells that produce intrinsic factor. Intrinsic factor is necessary for B12 absorption in the small intestine. A lack of B12 can also lead to specific neurological symptoms, including numbness, tingling, and difficulties with balance, because the vitamin is necessary for nerve health.
Folate, or Vitamin B9, is essential for DNA synthesis and proper red blood cell maturation; its deficiency can lead to megaloblastic anemia, characterized by abnormally large red blood cells. Since the body does not store large reserves of folate, a poor diet or certain medications can quickly deplete the body’s supply.
Impaired Kidney Function
The kidneys produce erythropoietin (EPO), a hormone that regulates the creation of red blood cells in the bone marrow. As individuals age, a decline in kidney function is common, often progressing to Chronic Kidney Disease (CKD). Even mild to moderate CKD can compromise the kidneys’ ability to produce an adequate amount of EPO.
Insufficient EPO production means the bone marrow does not receive the necessary hormonal signal for red blood cell production, resulting in a hypoproliferative anemia. The severity of the anemia is directly correlated with the degree of kidney function impairment.
Occult Blood Loss and Medication Effects
Occult blood loss refers to slow, chronic blood loss and contributes to iron deficiency anemia in the elderly. This type of bleeding commonly originates from the gastrointestinal (GI) tract due to conditions like peptic ulcers, colon polyps, or early-stage colorectal cancer. The continuous, small-volume loss of blood gradually depletes the body’s iron stores.
Certain medications commonly used by older adults can also cause or exacerbate anemia. Non-Steroidal Anti-Inflammatory Drugs (NSAIDs), such as ibuprofen or naproxen, are frequent culprits, causing irritation and bleeding in the stomach lining that contributes to occult blood loss. Other medications, including some chemotherapy agents and immunosuppressants, can directly suppress the bone marrow’s ability to produce all types of blood cells.