Causes and Risk Factors of Iron Deficiency Anemia

Iron deficiency anemia (IDA) is when a lack of iron reduces the body’s ability to make enough red blood cells, which are vital to carrying the oxygen from the lungs to the rest of the body. Without enough iron in the blood, you might feel weak, tired, and short of breath. 

Iron is necessary to make hemoglobin—the protein that helps red blood cells carry oxygen. IDA occurs because the body is low on iron.

There are many reasons why you might become iron deficient. Different risk factors increase your risk for IDA—some of which cannot be changed, and others that you might be able to change. 

Here is what you need to know about common causes and risk factors of iron deficiency anemia.

Common Causes

According to the American Society of Hematology, iron deficiency is the most common cause of anemia. IDA affects 5% of American women and 2% of American men.

Common causes of IDA include a diet that is low in iron, the body not being able to absorb iron, heavy menstrual bleeding, internal bleeding, pregnancy, chronic kidney disease, and chronic conditions that cause ongoing inflammation.

Inadequate Intake of Iron

IDA often occurs as a result of inadequate intake of iron from the diet. Many foods are rich sources of iron, including meat, fish, beans, legumes, spinach, and iron-fortified foods.

There are many reasons why a person may not be getting enough iron in their diet. It might be because they practice a vegetarian or vegan lifestyle and aren’t replacing meat with other iron-rich foods.

Other reasons include having an eating disorder, not having easy access to iron-rich foods, eating a diet low in iron-rich foods, or being unable to eat a complete or diverse diet.

Impaired Ability to Absorb Iron

Certain medical conditions or surgeries can interfere with how the body absorbs iron. Even if you are getting enough iron from your diet, having a condition like celiac disease, gastritis, or previous intestinal surgery, such as a gastric bypass, can limit the amount of iron the body can absorb.

Celiac disease is a digestive condition where your immune system reacts abnormally to gluten. Gastritis is inflammation of the stomach lining. Gastric bypass surgery is a kind of weight loss surgery that changes how the stomach and the small intestine process food.

Conditions like celiac disease and gastritis and surgeries like gastric bypass are called disorders of malabsorption. They can lead to decreased iron absorption and increase the risk for iron deficiency anemia.

Menstrual Bleeding

Menorrhagia, or heavy menstrual bleeding, can increase the risk for the development of iron deficiency anemia. This type of heavy blood flow can deplete the body’s iron storage.

Menstrual bleeding disorders account for 5% to 10% of iron deficiency cases. Menstrual bleeding can lead to severe anemia.

According to the Centers for Disease Control and Prevention (CDC), menorrhagia is menstrual bleeding that lasts seven or more days. Menorrhagia also refers to heavy bleeding, which according to the CDC can be determined if you need to change a pad or tampon after less than two hours or if there are quarter-size or larger clots.

If you experience this type of bleeding, you should see your doctor. They can prescribe treatments to reduce heavy flow and reduce the risk of anemia and other health problems.

Internal Bleeding

Medical conditions that cause internal bleeding, such as stomach ulcers and colon polyps, can lead to iron deficiency anemia.

People who experience gastrointestinal (GI) bleeding usually do not notice any obvious blood in their stools and may not experience bowel habit changes. One study reported in 2019 in the Danish Medical Journal found that more than 80% of people admitted to the hospital with upper GI bleeding were anemic.

While you may not know if you have internal bleeding, you may experience other symptoms associated with stomach ulcers and colon polyps. This might include severe pain in the mid to upper abdomen and dark or black stools.

Pregnancy

IDA is common during pregnancy. Globally, anemia in pregnancy is estimated to occur in 41.8% of pregnancies. There can be various reasons for anemia. How often IDA, specifically, occurs in pregnancy is unknown.

Pregnancy is a time when double the amount of iron is needed. The body needs iron to make more blood to supply oxygen to the growing fetus. If you don’t have enough iron stores or get enough iron while pregnant, you might develop IDA.

In pregnancy, IDA can lead to premature births and low birth weight babies. But IDA in pregnancy and pregnancy complications from it are preventable with iron supplementation, which can be a part of routine prenatal care.

Chronic Kidney Disease

IDA can be a complication of chronic kidney disease (CKD). CKD means the kidneys are damaged and can no longer filter blood correctly. This damage leads to waste and fluids building up in the body.

IDA occurs more often as kidney disease worsens. IDA is less common in the early stages of kidney disease and will get worse as the kidney disease progresses and kidney function is lost.

Inflammatory Conditions

According to the National Heart, Lung, and Blood Institute, many different chronic conditions that can lead to inflammation may also cause IDA. Inflammation causes the liver to make more of a hormone called hepcidin. This hormone will stop iron from leaving cells where it is stored and absorbed in the first part of the small intestine.

Even if a person has enough iron in their body, inflammation can affect how iron is absorbed and used. Without enough iron making its way to the blood, the body cannot make new red blood cells, and the red blood cells it does have will make less hemoglobin.

Talk to your doctor if you live with an inflammatory condition like inflammatory arthritis or inflammatory bowel disease and how your condition might increase your risk for IDA.

Genetics

Family and genetics may play a part in the development of IDA. Two inherited conditions—hemophilia and von Willebrand disease—can cause a person to lose iron because of excessive bleeding.

Females who have the gene for hemophilia and those who are symptomatic can experience heavy menstrual periods, which will add to their IDA risk.

Von Willebrand disease is an inherited blood disorder where blood doesn’t clot properly. This disorder makes it harder to stop bleeding, increasing the risk for IDA from an injury, surgery, or heavy menstrual bleeding.

Age

Some age groups may have an increased risk for IDA. This includes infants from 6 to 12 months old, children 1 to 2 years of age, teens, and elderly adults.

• Infants between 6 to 12 months are especially vulnerable to IDA if they are only fed breast milk or formula that is not iron-fortified. Babies who are born prematurely might be at a higher risk for IDA, as well as babies who drink cow’s milk before 12 months, rather than breast milk or iron-fortified formula.
• Children 1 to 2 years of age are also vulnerable to IDA if they consume a lot of cow’s milk. This is because cow’s milk is low in iron.
• Teens might develop IDA if they are not getting enough iron during periods of growth spurts.
• Elderly adults are at high risk for IDA, and iron deficiency is one of the most frequent causes of anemia in this group. It can affect health and quality of life, and is connected to negative outcomes, including hospitalizations and disability.

Environment

Lead poisoning from water or environmental sources can affect the body’s ability to make red blood cells. Chronic lead poisoning and absorption can inhibit the body’s ability to produce hemoglobin, increasing the risk for IDA.

Lifestyle

Certain lifestyle habits can increase a person’s risk for iron deficiency anemia. This might include:

• A vegetable and/or vegan diet: Not getting enough iron-rich foods, especially meat or fish, can result in a person getting less iron.
• Frequent blood donation: People who donate blood routinely are at an increased risk for IDA because blood donation can deplete their iron stores. Blood collection centers check donors before each donation and defer them if they show low red blood cell levels.
• Having an athletic lifestyle: Athletes, in particular young females, have a higher risk for IDA. Some contributing factors include inadequate dietary iron intake, menstruation, increased iron loss from sweating, and increased risk for GI bleeding and exercise-induced inflammation.

Summary

Iron deficiency anemia can result from low dietary iron intake, reduced absorption of iron from the diet, blood loss, impaired release of stored iron, or increased iron need in pregnancy. Age, certain genetic conditions, and some lifestyle choices are also risk factors.

A Word From Verywell

If you experience signs of iron deficiency anemia, reach out to your doctor. Some common symptoms of IDA include extreme fatigue, shortness of breath, heart palpitations, pale skin, headaches, and cold hands and feet. Your doctor can administer a simple blood test to determine the source of your symptoms.

Iron supplementation can help to restore iron to normal levels. If there is an underlying medical condition causing IDA, such as heavy menstrual bleeding, your doctor may prescribe additional treatments.