Lymphoma - Non-Hodgkin: Risk Factors

Approved by the Cancer.Net Editorial Board, 11/2022

ON THIS PAGE: You will find out more about the factors that increase the chance of developing non-Hodgkin lymphoma (NHL). Use the menu to see other pages.

What are the risk factors for NHL?

A risk factor is anything that increases a person’s chance of developing cancer. Although risk factors often influence the development of cancer, most do not directly cause cancer. Some people with several risk factors never develop cancer, while others with no known risk factors do. Knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.

The exact cause of NHL is not known, and most people diagnosed with NHL will not learn what caused it. However, the following factors may raise a person’s risk of developing NHL:

  • Age. The risk of NHL increases with age. The most common subtypes occur most often in people in their 60s and 70s.

  • Sex. An NHL diagnosis is slightly more common in men than women.

  • Bacterial infections. Some types of NHL are associated with specific infections. For example, some cases of mucosa-associated lymphoid tissue (MALT) lymphoma of the stomach are thought to be caused by an infection with bacteria called Helicobacter pylori. If this lymphoma is diagnosed very early, it will sometimes go away if the infection is cured with antibiotics. Infections may also cause other types of MALT lymphoma, including those affecting the lungs, tear glands, and skin.

  • Viruses. Viruses cause some types of NHL. The Epstein-Barr virus (EBV) is the virus that causes mononucleosis, also known as "mono," and it is associated with some types of NHL. These include Burkitt lymphoma, lymphomas occurring after an organ transplant, and, rarely, other lymphomas in people who are otherwise healthy. However, nearly everyone has EBV, so the virus is probably not the only factor that determines cancer risk. NHL that arises from EBV is likely the result of the body’s inability to regulate the virus. Therefore, people who have had mononucleosis do not necessarily have an increased risk of developing NHL in the future. In addition, hepatitis C infection has been associated with an increased risk of marginal zone lymphomas of the spleen (see Subtypes). Researchers have also found other viruses to be important in causing other, rare types of lymphoma, such as HIV (see below).

  • Immune deficiency disorders. Immune system disorders, such as HIV/AIDS, increase the risk of NHL, especially the aggressive B-cell lymphomas.

  • Autoimmune disorders. People with autoimmune disorders, such as rheumatoid arthritis and Sjögren syndrome, have an increased risk of developing certain types of NHL. Some drugs used to treat autoimmune disorders may increase the risk of NHL.

  • Organ transplantation. Organ transplant recipients have a higher risk of NHL. This is because of the drugs patients must take to reduce immune system function in order to protect the transplanted organ from rejection.

  • Previous cancer treatment. Previous treatment with certain drugs for other types of cancer may increase the risk of NHL. This is called a second cancer.

  • Chemical exposure. Exposure to certain chemicals may increase the risk of NHL. This may include pesticides, herbicides (like Agent Orange), and petrochemicals.

  • Genetic factors. Currently there are no widely accepted genetic tests to identify inherited risk factors for NHL or that reliably predict a person’s risk of developing NHL. These possible risks are being studied in ongoing clinical trials.

  • Vaccines. The relationship between vaccinations and lymphoma remains unclear and controversial. A number of studies have found an association between Bacillus Calmette–Guerin (BCG) vaccination and an increased risk of NHL. BCG is a vaccine for tuberculosis disease that is used to treat some cases of bladder cancer. However, research has also associated other vaccinations with a decreased risk of NHL, such as those for smallpox, cholera, yellow fever, influenza, measles, tetanus, and polio.

  • Breast implants. Having breast implants can increase the risk of breast lymphomas.

  • Exposure to ionizing radiation. This can include exposure to radiation from atomic bombs, nuclear reactor accidents, and medical radiation therapy.

  • Food/weight. There is some inconclusive evidence that being overweight or having a diet filled with fatty foods or red meat may slightly increase the risk of lymphoma.

The next section in this guide is Symptoms and Signs. It explains what changes or medical problems NHL can cause. Use the menu to choose a different section to read in this guide.