A risk factor is something that increases your chances of developing cancer.

It is possible to develop non-Hodgkin’s lymphoma with or without the risk factors listed below. However, the more risk factors you have, the greater your likelihood of developing non-Hodgkin’s lymphoma. If you have a number of risk factors, ask your health care provider what you can do to reduce your risk.

Risk factors for non-Hodgkin’s lymphoma include the following:

Medical Conditions

Non-Hodgkin’s lymphoma seems to occur more often in people with the following characteristics:

  • Have been infected with Epstein-Barr virus, which causes mononucleosis.
  • Are infected with the human immunodeficiency virus (HIV), which weakens the immune system.
  • Are born with an abnormally functioning immune system.
  • Have received radiation or chemotherapy for a different type of cancer.
  • Have been infected with human T-cell leukemia/lymphoma virus (HTLV-1). This virus is in the same viral family as HIV. It spreads in a similar fashion through blood, breast milk, and sexual relations. HTLV-1 is more common in Japan and the Caribbean than in the United States.
  • Have been infected with Helicobacter pylori ( H. pylori ), which causes stomach ulcers. This infection is associated with a specific type of non-Hodgkin’s lymphoma that develops in the stomach.


Some non-Hodgkin’s lymphomas are associated with the use of immunosuppressive drugs, such as azathioprine (Imuran) or cyclosporine (Sandimmune), that are used to prevent transplant rejection or to manage other conditions, such as rheumatoid arthritis. These drugs weaken your immune system response.

Advancing Age

The chance of developing non-Hodgkin’s lymphoma increases with age. Among 20-year olds, about three cases occur for every 100,000 people. That increases to 51.5 cases per 100,000 among 60-year-old men and 38 cases per 100,000 among 60-year-old women. Among people older than 75, the incidence is 80 cases per 100,000.


About 28,200 males will be diagnosed this year with non-Hodgkin’s lymphoma, compared with 25,700 females. Why slightly more men develop non-Hodgkin’s lymphoma is not known.

Chemical Exposure

People who work around pesticides, herbicides, fertilizers, and solvents have a greater chance of developing non-Hodgkin’s lymphoma than people who do not have this exposure. Researchers are still trying to determine what relationship exists between chemical exposures and non-Hodgkin’s lymphoma.

Ethnic Background

People of European descent are more likely to develop non-Hodgkin’s lymphoma than people of other ethnic groups. The reason is unknown.