Anemia occurs when the blood doesn’t have enough hemoglobin or red blood cells. This can happen if:

• The body doesn’t make enough hemoglobin or red blood cells.
• Bleeding causes the loss of red blood cells and hemoglobin faster than they can be replaced.
• The body destroys red blood cells and the hemoglobin that’s in them.

Also, some people can’t absorb vitamin B-12. This can lead to vitamin deficiency anemia, also called pernicious anemia.

Anemia of inflammation. Diseases that cause ongoing inflammation can keep the body from making enough red blood cells. Examples are cancer, HIV/AIDS, rheumatoid arthritis, kidney disease, and Crohn’s disease.

Aplastic anemia. This rare, life-threatening anemia occurs when the body doesn’t make enough new blood cells. Causes of aplastic anemia include infections, certain medicines, autoimmune diseases, and being in contact with toxic chemicals.

Anemias linked to bone marrow disease. Diseases such as leukemia and myelofibrosis can affect how the bone marrow makes blood. The effects of these types of diseases range from mild to life-threatening.

Hemolytic anemias. This group of anemias is from red blood cells being destroyed faster than bone marrow can replace them. Certain blood diseases increase how fast red blood cells are destroyed. Some types of hemolytic anemia can be passed through families, which is called inherited.

Sickle cell anemia. This inherited and sometimes serious condition is a type of hemolytic anemia. Unusual hemoglobin forces red blood cells into an unusual crescent shape called a sickle. These irregular blood cells die too soon. That causes an ongoing shortage of red blood cells.

Risk factors of Anaemia

These factors can increase the risk of anemia:

A diet that doesn’t have enough of certain vitamins and minerals. Not getting enough iron, vitamin B-12, and folate increases the risk of anemia.

Problems with the small intestine. Having a condition that affects how the small intestine takes in nutrients increases the risk of anemia. Examples are Crohn’s disease and celiac disease.

Menstrual periods. In general, having heavy periods can create a risk of anemia. Having periods causes the loss of red blood cells.

Pregnancy. Pregnant people who don’t take a multivitamin with folic acid and iron are at an increased risk of anemia.

Ongoing, called chronic, conditions. Having cancer, kidney failure, diabetes or another chronic condition increases the risk of anemia or chronic disease. These conditions can lead to having too few red blood cells. Slow, chronic blood loss from an ulcer or other source within the body can use up the body’s store of iron, leading to iron deficiency anemia.

Family history. Having a family member with a type of anemia passed through families, called inherited, can increase the risk of inherited anemias, such as sickle cell anemia.

Other factors. A history of certain infections, blood diseases, and autoimmune conditions increases the risk of anemia. Drinking too much alcohol, being around toxic chemicals, and taking some medicines can affect the making of red blood cells and lead to anemia.

Age. People over age 65 are at increased risk of anemia.