Researchers have found a few risk factors that make a person more likely to develop Waldenstrom macroglobulinemia. However, most people with these risk factors never develop the disease. Even if a patient with WM does have one or more risk factors, it is impossible to know for sure how much that risk factor contributed to causing the cancer.

Monoclonal gammopathy of undetermined significance: Monoclonal gammopathy of undetermined significance (MGUS) is an abnormality of antibody-producing cells that is related to multiple myeloma and Waldenstrom macroglobulinemia. In MGUS, like WM and multiple myeloma, abnormal cells in the bone marrow make a large amount of one particular antibody -- when this happens it is called a monoclonal gammopathy. As long as the patient has no problems from the abnormal cells or the antibody, it is called MGUS. Generally, the abnormal cells in MGUS make up less than 10% of the bone marrow and the amount of abnormal protein in the blood is not very high (<3g/dl). In most cases, MGUS causes no health problems, but up to 25% of people with MGUS will go on to be diagnosed with a cancer (either multiple myeloma, WM, or another lymphoma) over the 20 years after diagnosis.

Aging: Age is a significant risk factor. This disease is rare among people younger than 50 years old.

Race: Waldenstrom macroglobulinemia is more common among whites than among African Americans. In contrast, multiple myeloma is about twice as common among African Americans as white Americans. The reasons for these differences are not known.

Sex: Men are more likely than women to develop this disease.

Heredity: Genetic factors may play a role. In one study, about 5% of patients with Waldenstrom macroglobulinemia had a close relative with the disease, and another 15% of WM patients had a relative with another type of lymphoma.

Hepatitis C: A recent study has shown that people with chronic hepatitis C infection develop WM over twice as often as people without the virus.