A risk factor [2] 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. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.

The causes of myeloma are not known or well understood, and there are currently no known ways to prevent it. There are also no strong risk factors for myeloma. Mutations in plasma cells are acquired, not inherited, so having a relative with the disease usually does not mean another family member is at higher risk for developing it. There appears to be a very slight increase in the incidence of the disease in first-degree relatives (parents or siblings) of people with multiple myeloma, but this link is not yet shown to be genetic.

The following factors can raise a person's risk of developing myeloma:

Age. Myeloma occurs most commonly in people over 60. The average age at diagnosis is 70. Only 2% of cases occur in people under 40.

Race. Myeloma occurs twice as frequently in black people than in white people for unclear reasons.

Exposure to radiation and chemicals. People who have been exposed to radiation or to asbestos, benzene, pesticides, and other chemicals used in rubber manufacturing may be at higher risk for developing myeloma.

Personal history. People with a history of a solitary plasmacytoma are at greater risk for developing multiple myeloma.

Monoclonal gammopathy of unknown significance (MGUS). A person with a low level of a certain antibody protein in his or her blood, called the M protein, have a 1% chance of developing myeloma or another blood-related cancer called lymphoma per year (See Staging [3] for more information).

Gender. Myeloma is slightly more common in men.