Which of the following is NOT a cause of anemia of chronic disease?

Anemia of chronic disease (ACD) is a type of anemia that occurs in the context of chronic illness, inflammation, or malignancy. It is characterized by a decrease in red blood cell production and is often linked to the body's reaction to long-term health issues, leading to changes in iron metabolism, erythropoietin levels, and overall red blood cell lifespan.

The factors that typically contribute to ACD include infections, inflammatory states, and various cancers. Infections can lead to systemic inflammatory responses that suppress red blood cell production and alter iron distribution. Inflammation from autoimmune diseases or chronic conditions can inhibit erythropoiesis and increase hepcidin production, further limiting iron availability for hemoglobin synthesis. Similarly, cancer can result in ACD through direct effects on the bone marrow or through the inflammatory responses associated with tumors.

In contrast, vitamin D deficiency is not a recognized direct cause of anemia of chronic disease. While vitamin D plays a role in various bodily functions, including bone health and immune regulation, its deficiency does not produce the characteristic changes in iron metabolism or red blood cell production seen in ACD. Therefore, it is not associated with the same pathological mechanisms as the other conditions listed and is not regarded as a contributor to anemia within