What are the risk factors for non-Hodgkin lymphoma?
A risk factor is something that affects a person's chance of getting a disease like cancer. Some risk factors, such as smoking, can be controlled. Others, like a person's age or race can't be changed. But risk factors don't tell us everything. Having a risk factor, or even several risk factors, does not mean that you will get the disease. And many people who get the disease may have had few or no known risk factors. Even if a person with non-Hodgkin lymphoma (NHL) has a risk factor, it is often very hard to know what part that risk factor may have played in the lymphoma.
Scientists have found a few risk factors that could make a person more likely to get lymphoma. There are many types of lymphoma, and some of these factors have been linked only to certain types.
Getting older is a strong risk factor for lymphoma overall. Most cases are found in people in their 60s or older. But some types of lymphoma are more common in younger people.
Overall, the risk of NHL is higher in men than in women, but there are certain types that are more common in women. The reasons for this are not known.
In the United States, whites are more likely than African Americans or Asian Americans to get NHL.
Exposure to certain chemicals
Some studies have suggested that chemicals such as benzene and certain weed- and insect-killers may be linked with an increased risk of NHL. More research is needed to see if this is true.
Some chemotherapy drugs used to treat other cancers may increase the risk of developing NHL many years later. But it's not yet clear whether this is because of the disease itself or if it is an effect of the treatment.
Survivors of atomic bombs or nuclear reactor accidents have a higher risk of many kinds of cancer, including NHL. People treated with radiation for some other cancers also have a slightly higher risk of getting NHL later in life. The risk is greater if both radiation and chemotherapy were used.
Weakened immune systems
People with weakened immune systems are at increased risk for NHL. For example, patients who have organ transplants (kidney, heart, liver) are treated with drugs that suppress their immune system to keep it from attacking the new organ. These patients have an increased risk of developing NHL. The human immunodeficiency virus (HIV) can also weaken the immune system, and people with HIV are at increased risk for NHL.
Some children are born with an immune system that doesn't work the way it should. These children have a higher risk of developing NHL.
In autoimmune diseases, the immune system sees the body's own tissues as foreign and attacks them, as it would a germ. Some autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus (SLE, or lupus), celiac sprue, and others have been linked with an increased rate of NHL.
Some infections may raise the risk of NHL in different ways.
Infections that directly change lymphocytes
Some viruses can affect the DNA of lymphocytes, helping to change them into cancer cells. A virus called HTLV-1 increases the risk of NHL. Epstein-Barr virus (EBV) has also been linked to lymphomas. In the United States, EBV is mainly linked to lymphoma in patients infected with HIV. HIV itself can weaken the immune system, which raises the risk for NHL.
Another virus called HHV can infect lymphocytes and lead to a rare kind of lymphoma called primary effusion lymphoma. This is more common in patients infected with HIV.
Infections that stimulate the immune sytsem
Some long-term infections may increase the risk of lymphoma by forcing a person's immune system to be on constant alert. As more lymphocytes are made to fight the infection, there is a greater chance that genetic mistakes can happen, which might lead to lymphoma. When an infection has caused lymphoma, treating the infection can often help the lymphoma in early stages.
A type of bacteria that causes stomach ulcers (Helicobacter pylori) can also cause some lymphomas of the stomach. Because of this, antibiotics might be helpful in treating some people who have already developed lymphomas of the stomach.
Reports have suggested that infection with the hepatitis C virus might be another risk factor for some types of lymphomas.
Body weight and diet
Some studies suggest that being very overweight (obese) might increase the risk of NHL. Other studies have also suggested that a diet high in fat and meats may raise your risk. More research is needed to confirm these findings. In any case, keeping at a healthy weight and eating a healthy diet have many known health benefits.
Last Medical Review: 04/18/2013
Last Revised: 04/18/2013